An-Najah National University Faculty of Graduate Studies EPIDEMIOLOGY, CHARACTERISTICS, AND RISK FACTORS OF SURGICAL SITE INFECTIONS IN A TERTIARY CARE HOSPITAL IN WEST BANK: A RETROSPECTIVE COHORT STUDY By Rawan Khalil Jeetawi Supervisor Dr. Souad Belkebir This Thesis is Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Infectious Diseases Prevention and Control, Faculty of Graduate Studies, An-Najah National University, Nablus, Palestine. 2024 ii EPIDEMIOLOGY, CHARACTERISTICS, AND RISK FACTORS OF SURGICAL SITE INFECTIONS IN A TERTIARY CARE HOSPITAL IN WEST BANK: A RETROSPECTIVE COHORT STUDY By Rawan Khalil Jeetawi This Thesis was Defended Successfully on 26/12/2024 and approved by Dr. Souad Belkebir Supervisor Dr. Kamal Dumaidi External Examiner Dr. Zaher Nazal Internal Examiner iii Dedication This thesis is dedicated to my dearly loved mother, who has meant and still means the world to me. Even though she is no longer among us, her memories continue to influence my life. For my family and valued friends who support and encourage me through this journey. iv Acknowledgments I would like to express my gratitude to my supervisor, Dr. Souad Belkebir, for her invaluable guidance and assistance during this project. who have offered me an enormous amount of guidance and encouragement. I am incredibly appreciative that I had a mentor who were not just kind and understanding but also excellent academic leaders. We would like to extend out acknowledgement to Dr. Abdurrahman Aid for his guidance and assistance with the logistic regression model. Many thanks to Najah National University Hospital for the opportunity to have this data and for facilitating access to the patient file. v Declaration I, the undersigned, declare that I submitted the thesis entitled: EPIDEMIOLOGY, CHARACTERISTICS, AND RISK FACTORS OF SURGICAL SITE INFECTIONS IN A TERTIARY CARE HOSPITAL IN WEST BANK: A RETROSPECTIVE COHORT STUDY I declare that the work provided in this thesis, unless otherwise referenced, is the researcher’s own work, and has not been submitted elsewhere for any other degree or qualification. vi List of Contents Dedication ...................................................................................................................... iii Acknowledgments ........................................................................................................ iv Declaration ...................................................................................................................... v List of Contents ................................................................................................................ vi List of Tables ................................................................................................................. viii List of Figures .................................................................................................................. ix List of Appendices ............................................................................................................ x Abstract........................................................................................................................... xi Chapter One: Introduction ................................................................................................ 1 1.1 Background ................................................................................................................. 1 1.2 Epidemiology of SSIs ................................................................................................. 5 1.3 Methodology differences in SSI surveillance ............................................................. 7 1.4 Risk indexes ................................................................................................................ 9 1.5 SSI risk factors .......................................................................................................... 10 1.5.1 Age ......................................................................................................................... 10 1.5.2 Gender .................................................................................................................... 11 1.5.3 Obesity ................................................................................................................... 11 1.5.4 Diabetes ................................................................................................................. 12 1.5.5 Smoking ................................................................................................................. 12 1.5.6 Nutritional status .................................................................................................... 13 1.5.7 Immunocompromised patient ................................................................................ 13 1.5.8 ASA score .............................................................................................................. 14 1.5.9 Bathing with chlorhexidine before surgery ........................................................... 15 1.5.10 Hair removal ........................................................................................................ 15 1.5.11 Normothermia and blood loss .............................................................................. 15 1.5.12 Type of surgical procedure .................................................................................. 16 1.5.13 Wound classification. ........................................................................................... 17 1.5.14 Duration of operation ........................................................................................... 17 1.5.15 Antibiotic prophylaxis ......................................................................................... 18 vii 1.5.16 Remote site infection ........................................................................................... 19 1.6 Pathogens and patterns of resistance ........................................................................ 23 1.7 The significance of the study .................................................................................... 25 1.8 Research Question .................................................................................................... 26 1.9 Objectives ................................................................................................................. 26 1.9.1 Main objective ....................................................................................................... 26 1.9.2 Specific Objectives ................................................................................................ 26 Chapter Two: Methodology ............................................................................................ 27 2.1 Study Design ............................................................................................................. 27 2.2 Study time, setting, and population .......................................................................... 27 2.3 Inclusion’s criteria .................................................................................................... 27 2.4 Exclusion’s criteria ................................................................................................... 27 2.5 Sample size calculation ............................................................................................. 28 2.6 Study variables .......................................................................................................... 28 2.7 Duration of follow-up ............................................................................................... 30 2.8 Data collection .......................................................................................................... 30 2.9 Data analysis ............................................................................................................. 30 2.10 Ethical Considerations ............................................................................................ 31 Chapter Three: Result ..................................................................................................... 32 3.1 The result of the study .............................................................................................. 32 3.2 Odds ratios for significant variables ......................................................................... 41 Chapter Four: Discussion of Results .............................................................................. 43 4.1 Discussion ................................................................................................................. 43 4.2 Strengths and limitations of the study ....................................................................... 50 4.3 Conclusions ............................................................................................................... 50 4.4 Recommendations ..................................................................................................... 50 List of Abbreviations ...................................................................................................... 52 Reference ........................................................................................................................ 53 Appendices ...................................................................................................................... 62 ب ............................................................................................................................... الملخص viii List of Tables Table 1: Summary of SSI risk factors and its pathophysiology ”Intrinsic and Extrinsic factors“ .............................................................................................................. 21 Table 2: Summary of SSI risk factors and its pathophysiology ”pre-intra-post procedure “ ....................................................................................................... 22 Table 3: The independent variable, operational definition, and the type of measurement ..................................................................................................... 29 Table 4: Sociodemographic and clinical characteristics of study participants (N=1157) .......................................................................................................... 33 Table 5: Procedure -related characteristics of the patients (N:1157) .............................. 35 Table 6: Intrinsic and extrinsic factors distribution of the study population per SSI (n = 1157) ................................................................................................................. 36 Table 7: Producer-risk factor distribution of the study population per SSI (n = 1157) .. 37 Table 8: Incidence of SSI based on the surgical type of infection ................................. 39 Table 9: Most common pathogen total N: 77 ................................................................. 40 Table 10: Multivariate analysis of risk factors associated with surgical site infection .. 42 ix List of Figures Figure 1: Abdominal wall cross-section showing the CDC/NHSN surgery site infection categories ............................................................................................................ 2 Figure 2: The incidence of SSI at Low- and middle-income countries ............................ 6 Figure 3: Components of the ideal SSI surveillance cycle ............................................... 9 Figure 4: Pathogenic microorganism distribution among research participants with SSI at DCSH from July 22 to October 25, 2016 ..................................................... 24 Figure 5: Surgical site infection rate at NNUH 2018-2020 ............................................ 32 Figure 6: The incidence of SSIs. The number of surgeries and surgical site infections (SSIs) for each category are shown in the bar chart ......................................... 38 x List of Appendices Appendix A: Institutional Review Board (IRB) approval. ............................................. 62 Appendix B: Case report form of surgical producer denominator’s, prevention of surgical site infection and surgical site infection....................................... 63 xi EPIDEMIOLOGY, CHARACTERISTICS, AND RISK FACTORS OF SURGICAL SITE INFECTIONS IN A TERTIARY CARE HOSPITAL IN WEST BANK: A RETROSPECTIVE COHORT STUDY By Rawan Khalil Jeetawi Supervisor Dr. Souad Belkebir Abstract Background: Surgical site infections (SSIs) are significant complications following surgery, impacting patient recovery and increasing healthcare costs. SSIs can lead to prolonged hospitalization, excessive medical expenses, and even death. Identifying risk factors and implementing effective prevention strategies is essential to improve patient safety. The incidence of SSIs is notably higher in developing nations, ranging from 2.5% to 41.9%. However, data from Palestine is scarce. This study aims to determine the SSI incidence among patients at An-Najah National University Hospital (NNUH) from 2018 to 2020 and identify associated risk factors. Methods: This analytical retrospective cohort study included 1,157 patients who underwent surgery between January 2018 and December 2020 at NNUH. Sociodemographic and clinical data were collected and analyzed using descriptive and analytical methods, including binary logistic regression to assess potential risk factors. A significance level of 5% was applied, and IBM SPSS Version 21 was utilized for data analysis. Results: The study found an overall SSI incidence rate of 7.65% among 1,157 surgical patients. The rate decreased from 18.2% in 2018 to 6.6% in 2019, and further to 0.6% in 2020. Higher SSI rates were observed in patients undergoing prosthesis implantation, longer surgical procedures, and non-laparoscopic surgeries (p ≤ 0.05). Additionally, patients with an ASA index of IV or higher had a significantly increased risk (p < 0.001). Logistic regression indicated that surgeries lasting over two hours were approximately 17 times more likely to result in SSIs (p < 0.001), while those with prosthesis implants were nine times more likely (p = 0.002). Contaminated wounds increased infection risk by 23 times (p = 0.005), and each additional hospital day raised the SSI odds by 4.6% (p < 0.001). xii Conclusions: The SSI surveillance program at NNUH underscores the importance of minimizing surgery duration, managing blood glucose and temperature post-surgery, and adhering to infection control policies to reduce SSI incidence. Further research is needed to evaluate the effectiveness of these strategies across diverse surgical settings and patient demographics. Keywords: surgical site infections, risk factors, healthcare associated infections (HAIs), Clean surgery. 1 Chapter One Introduction 1.1 Background Health-care-associated infections (HAIs), nowadays are a serious public health issue. SSIs, which result in a high death rate, major morbidity, a significant prolongation of hospitalization, and higher care costs, are among the most pertinent HAIs (1–3). They are the main reason for readmissions, can result in problems like delayed wound healing and revision surgery, and can increase a patient's susceptibility to hospital-acquired infections by lengthening their hospital stay (2). SSIs are defined as infections that appear at the site of the incision in surgical patients within 30 days after the procedure if there is no implant, or within a year if there is (4– 6). SSIs affect more than 1 in 10 people who have surgery in low-middle-income countries (LMICS); people in these countries are 3-5 times more likely than people in high- income countries to have SSIs. In the United States, SSIs impact 1% of surgical patients and result in over 400,000 additional hospital days for patients, which costs $10 billion annually (7). In Palestine, a multi-center, prospective cohort study conducted at 11 participating hospitals (4 in Gaza and 7 in the West Bank) showed that, in spite of Palestine's poor economic circumstances, the SSI rate was comparable to those of high- income nations (9.6% vs. 9.4%) (8). Consequently, surveillance of SSIs with adequate data feedback to surgeons has been found to be an important component of the SSI risk reduction strategy (6,7). Active, patient-based, prospective surveillance is required for SSI monitoring. To detect SSIs after inpatient operating procedures, concurrent and post-discharge surveillance measures should be implemented, as well as post-discharge surveillance for outpatient operative procedures (6, 7). SSI surveillance is defined by the Centers for Disease Control and Prevention (CDC)and National Healthcare Safety Network (NHSN) as three types of wound infections: superficial, deep incisional, and organ/space SSIs (6). 2 The phases of SSI are described in the diagram below Figure 1. Figure 1 Abdominal wall cross-section showing the CDC/NHSN surgery site infection categories “Adapted from: NHSN categorization of SSIs. (From Horan TC, Gaynes RP, Martone WJ, Jarvis WR, Emori TG. CDC definitions of nosocomial surgical site infections, 1992: a modification of CDC definitions of surgical wound infections. Infect Control Hosp Epidemiol. 1992;13 (10): 606-608; with permission)” (9). For an infection to be classified as a superficial incisional surgical site infection (SIP), it must have commenced within 30 days post-operative and be limited to the skin and subcutaneous tissue. Deep incisional surgical site infection (DIP) is an infection associated with surgical procedures, affecting the deep soft tissues. It manifests after 30 days post-operation in the absence of an implant, or after one year if an implant is present, involving fascia and muscle layers (6, 10). An organ or space SSI is defined as an infection in any region of the body other than the incision that was opened or modified during the procedure, that appears to be connected 3 to the surgical procedure, and that occurs within 30 days if no implant was used or within a year if one was. (10) The criteria of SSI according to each classification are as the following (6). Superficial incisional: The event occurs within 30 days of the NHSN surgical procedure (day 1 reflects the procedure date), includes just the incision's skin and subcutaneous tissue, and the patient possesses at least one of the following: a. Purulent discharge. b. Organism (s) detected by a culture-based or nonculture-based microbiologic testing method from an aseptically obtained specimen from the superficial incision or subcutaneous tissue used for clinical diagnosis or treatment. c. When a surgeon or physician purposefully opens a superficial incision, no culture- based or non-culture-based examination of the shallow incision or subcutaneous tissue is carried out. d. At least one of the following symptoms or signs is present in the patient: localized erythema, heat, swelling, or discomfort or tenderness. Deep incisional: The event date occurs within 30 or 90 days after the NHSN operational procedure (day 1 reflects the procedure date), and includes the deep soft tissues of the incision (such as the layers of muscle and fascia), and the patient possesses at least one of the following: a. Purulent discharge from the deep wound b. A deep incision that a physician or surgeon purposefully opens or aspirates. c. Organism(s) detected by a culture-based or nonculture-based microbiologic testing method from an aseptically obtained specimen from the superficial incision or subcutaneous tissue used for clinical diagnosis or treatment. The patient develops at least one of the symptoms or indicators listed below: fever (above 38°C); localized soreness or pain c. an abscess or other infection-related sign involving the deep incision found by imaging, histopathologic, or gross anatomical examination. Organ/Space: The event date occurs within 30 or 90 days after the NHSN operational procedure (day 1 reflects the procedure date), includes any part of the body that is 4 opened or modified during the surgical operation that is deeper than the layers of muscles or fascial, and the patient possesses at least one of the following: a. Purulent drainage from a drain that is inserted into the organ or space (such as an open drain, T-tube drain, closed suction drainage system, or CT-guided drainage). b. Organism(s) detected from tissue or fluid within the organ or space using a microbiologic testing technique based on culture or non-culture that is carried out for clinical diagnosis or therapy. c. an abscess or other infection-related evidence involving the organ or space that is discovered by:  A gross anatomical examination.  A histopathologic examination.  Imaging test evidence that is conclusive or inconclusive for infection and satisfies at least one requirement for a particular organ or space infection site specified in the Surveillance Definitions for Specific Types of Infections. There are a variety of reasons why a patient may develop SSI, which can be classified as patient specific or procedure-specific, with both factors being controllable or non- modifiable (11, 12). Obesity, current smoking status, high serum glucose preoperatively or postoperatively above 180 mg/dL, poor nutrition status of the patient, and nasal carriage of Staphylococcus aureus are all modifiable patient-specific variables (5–7). Male gender, advanced age (over 50 years), diabetes mellitus, and other characteristics are non-modifiable risk factors for SSIs. (12,13) is employed for evaluating the level of a patient's "physical state" or "illness" before choosing an anesthetic or conducting surgery. An ASA score of I–IV indicates that the patient has significant systemic disease; a score of III or higher indicates this (14). By the end of the 1960s, the field of hospital infection prevention had gotten a lot more attention. (15) The study's primary focus was on the nature and quantities of bacteria that contaminate wounds, as well as the characteristics of human microbial flora in disease states. Consequently, there has been a major advancement in the use of antibiotics, both preventive and therapeutic, in surgical patients (16). 5 Antibiotic prophylaxis can lower the incidence of postoperative wound infections, but it also raises the selective pressure favoring the emergence of antimicrobial resistance, as well as exposing patients to reactions and Clostridium difficile infections (12, 16). First-generation cephalosporin, such as cefazolin, is still the prophylactic, broad- spectrum antibiotic of choice for the majority of surgeries. Preoperative intravenous antibiotics should be given within 60 minutes of the incision, according to the latest standards, including therapeutic antibiotic guidelines. For the majority of surgeries, a single preoperative dose is sufficient. Intravenous antibiotics (up to 24 hours after surgery) are only required in specific instances, such as some cardiac and vascular procedures and lower limb amputations (16, 17). Most diseases are caused by endogenous causes, such as bacteria on the patient's skin. Staphylococcus aureus is the most frequently found isolate linked to the development of SSIs and the most frequently found microorganism found on the skin. Exogenous sources of bacteria that contribute to SSIs include transient flora from surgical team members' hands, fingernails, forearms, and jewelry that are transported to patients. Instruments, tools, and other materials used in the operating room may also become contaminated with bacteria if they are not properly sterilized (18). Most studies have found that Staphylococcus aureus, Staphylococcus epidermis, Pseudomonas, Klebsiella spp., and Escherichia coli are the most common causal pathogens. (19–22)Despite the latest innovations, wound infections remain the most common nosocomial infection in surgical and wound treatment systems, particularly in surgical patients. An estimated 31% of all HAIs and 20% of readmissions following surgery were attributed to SSIs (23). 1.2 Epidemiology of SSIs Globally, SSI rates have been estimated to range from 2.5 to 41.9%. In addition, surgical mortality is 10 times higher in developing nations than in wealthy ones (23,24). However, the incidence differs between developed and developing countries; patients in the former group are more likely to be impacted than those in the developing countries, SSI was found to be 2.6 %, 1.6 % in Germany, and 2.9 % in different countries (25, 26). With a pooled incidence of 11.8 per 100 surgical patients, it is most common in low- 6 and middle-income countries (23). Patients with SSIs are 2–11 times more likely to die than those without SSIs (11). Figure 2 shows the incidence of Low- and middle-income countries. Figure 2 The incidence of SSI at Low- and middle-income countries Adapted from:” The global problem of post-operative infections. https://www.bbraun.co.za/en/products-and-therapies/degenerative-spinal-disorders/ sterile-supply/tray-organizing-manager/infection-prevention-cssd.html (27). According to a recent research investigation that followed the PRISMA procedures for the systematic review and meta-analysis of 43 publications from 39 different countries, the global pooled incidence of SSI was 2.5% (95% CI: 1.6, 3.7), with Africa having the greatest incidence. (28) Also, a systematic review and meta-analysis in 2019 was conducted in developing countries in Africa/Middle East, Latin America, Asia, and China found that the overall prevalence of SSIs was 10% (29). The International Nosocomial Infection Control Consortium (INICC) report, covering data from 30 countries between 2005 and 2010, reveals significant insights into the epidemiology and impact of SSIs globally. It's been found that SSIs in low-income 7 countries (LICs) can be notably higher compared to high-income countries. INICC research has reported incidence rates of SSIs ranging from approximately 10% to 20% or higher in certain LIC settings. (30) SSI is the leading cause of healthcare-associated infections (HAI) in LMICs and the most frequent surgical complication (31). These discrepancies can be explained in a number of ways. Aside from the quality of infection prevention measures and patient demographic disparities, it may reflect poor quality of care (32). SSI becomes obvious only after discharge, between 10 and 82 % of SSI cases are discovered after patients have been discharged. In countries with limited resources, the postoperative stay is frequently longer (33–36). 1.3 Methodology differences in SSI surveillance Many SSI surveillance strategies have been proposed in the literature, each with its own set of benefits and drawbacks. The approaches for detecting SSI can be classified as active or passive. Infection control personnel identify SSI by checking patient records and laboratory findings, discussing patients with the ward staff, and calling patients after discharge using an active strategy. SSIs are recognized passively by infection control professionals or a surgeon inspecting the surgical site. It's feasible to mix and match elements in both ways (6). A surveillance-based strategy for preventing SSIs that focuses on five key areas determined by global experts. These five areas are as follows: 1. gathering reliable, high-quality data; 2. connecting HAIs to financial constraints, emphasizing the necessity of giving infection prevention initiatives top priority; 3. integrating SSI surveillance into infection prevention and control (IPC) programs to implement structural changes, improve procedural skills, and change the behaviors of healthcare workers; 4. giving IPC training for healthcare workers in LMICs top priority in order to conduct broad-based surveillance and to create and implement locally applicable IPC programs; and 5. creating an extremely precise and impartial international system for defining SSIs that can be easily translated globally (37). 8 The most accurate technique of surveillance is the active method, which involves daily inspection of the surgical site beginning 24–48 hours after surgery. While the direct technique is the gold standard for research, it is rarely employed in practice due to its resource needs and impracticality. The passive method of SSI surveillance, on the other hand, is less time-consuming and can be easily implemented by infection preventionist specialists during surveillance rounds (12). When one study compared the sensitivity and specificity of several passive approaches to the gold standard of direct surveillance, they discovered that the sensitivity was 70% and the specificity was 100%. Review of nursing notes, International Classification of Diseases, ninth revision codes, and antimicrobials administered were all components of the indirect approaches that were linked to the highest sensitivities (38). The national and international surveillance systems for nosocomial infections acknowledge the different obstacles to SSI surveillance in LMICs and offer a set of basic elements of a surveillance program that can be first put into place at the departmental and institutional level. This is essential to guarantee prompt action for anomalous findings and to modify surgical ward practices. After the program has gained experience and confidence, it can then be expanded to a national level. 9 Figure 3 Components of the ideal SSI surveillance cycle Adapted from: “Edmond MB. National and international surveillance systems for nosocomial infections. In: Wenzel RP, editor. Prevention and control of nosocomial infections. 4th ed. Philadelphia: Lippincott Williams & Wilkins; 2003. pp. 109e19.47” (39). 1.4 Risk indexes Multiple techniques for SSI prediction and stratification have been developed. Classification of surgical wounds was the only variable used to predict SSI. Two CDC efforts: The National Nosocomial Infections Surveillance (NNIS) system and the Research on the Efficacy of Nosocomial Infection Control Study (SENIC) added additional predictor elements to the SSI risk scores. The observed misclassifications of incisions and the fact that the SSI risk varied by several percentages even within the group with clean wounds served as the justification for this (40, 41). 10 Every operation has its own unique NNIS risk index. The index values, which range from 0 to 3, are determined by three independent and equally weighted variables: contaminated or dirty wounds, ASA score III or higher, and operation over T hours (where T varies depending on the operative procedure being performed; surgeries beyond the 75th percentile of surgery duration score one point) (40,42). The use of the risk index was not utilized in this particular study due to the characteristics of the population being studied; the focus was on identifying specific risk factors for SSIs rather than using a generalized risk index. 1.5 SSI risk factors Different risk variables related to patients and operations have been investigated to see how much they influence the likelihood of SSI. Information about the surgical procedure and patient characteristics that may influence the development of SSI is useful in two ways: (1) it allows for better stratification of procedures, resulting in more comprehensive surveillance data, and (2) knowing risk factors before surgery may allow for targeted prevention measures. Risk stratification also allows for the identification of changes in SSI rates that are not related to differences in unchangeable factors, such as the patient's vulnerability (40, 43). Patient variables 1.5.1 Age Most of the studies reported that age above 50 has been associated with an increased risk of SSI. According to Kaye's research, which was a cohort study conducted at Duke University Medical Center in Durham, North Carolina, included patients who underwent surgery between February 1991 and July 2002, the chance of infection climbed by 1.1% between the ages of 17 and 65, then declined by 1.2% per year after that. These results indicate that SSI risk is significantly influenced by age, with older patients being at higher risk. The immune system of older persons frequently deteriorates, making the body less effective at fighting illnesses. Additionally, wound healing is hampered by age-related changes in the flexibility of the skin and tissue, and wound recovery and infection resistance are further compromised by prevalent comorbidities in 11 older patients, such as diabetes, vascular disease, and malnutrition. When combined, these physiological variables make older individuals more vulnerable to SSIs (44). 1.5.2 Gender SSIs can affect both men and women, although the causes of these infections can differ. The risk of SSIs varies by gender and is influenced by a variety of factors, including biological differences; gender differences in skin flora can affect the risk of SSI. Males have thicker skin and produce more sebum, which may impact bacterial colonization and raise the risk of infection. (45) Hormonal impacts; while testosterone in men may cause a greater inflammatory response after surgery, estrogen in women has anti-inflammatory qualities that might speed up the healing of wounds (45). Surgical procedures; when it comes to procedures involving the pelvic or reproductive regions, women are more at risk, while it was noticed that males were more prone to get infections following cardiac surgery. (46) In addition, different health-seeking behaviors among both genders may also have an impact as women are typically more proactive in seeking medical attention and following postoperative instructions than men. Men prefer to delay seeking medical assistance until after surgery, according to research by Olsen et al. This may lead to an earlier diagnosis and treatment of SSIs in women (47). 1.5.3 Obesity One established risk factor for SSIs is obesity, which is defined as a body mass index (BMI) greater than 30 kg/m2. (48) A prospective cohort study of 206 National Health Service (NHS) hospitals in England found that depending on the kind of surgery, obesity was linked to an increase in the adjusted risks of developing SSI of 1.1– 4.4 times higher than that of normal weight (49). Because obesity reduced wound healing, changed immunological responses, and caused difficulties with wound management after surgery, because adipose tissue is less vascularized, obesity can delay wound healing by lowering blood flow and oxygen supply to tissues. Adipose tissue also raises inflammatory reactions, which can weaken immunity and increase the risk of infection. 12 Obese individuals also have a harder difficulty undergoing surgery, which frequently leads to longer operating periods and wider incisions, which increases the risk of SSIs. (50) In order to lower the incidence of SSIs in obese patients, these concerns highlight the significance of focused preventative measures, including preoperative weight management, improved surgical methods, and careful postoperative care. 1.5.4 Diabetes Diabetes can cause immunological compromise, delayed wound healing, microvascular problems, hyperglycemia, and related comorbidities; it is therefore a significant risk factor for SSIs (48, 51). Patients with diabetes have a markedly increased risk of SSIs after a variety of surgeries, including orthopedic, cardiac, and gastrointestinal procedures, because blood vessels can be damaged by high blood glucose, which lowers blood flow to the surgical site and limits the delivery of nutrients and oxygen that are necessary for healing. Additionally, diabetes weakens the immune system, which makes it more difficult for the body to fend off infections. Furthermore, high blood sugar encourages the growth of bacteria, raising the risk of infection at the wound site. When combined, these variables increase the risk of SSIs following surgery for diabetics. Keeping blood glucose levels 180 mg/dL or below, prior to and after surgery has been demonstrated to effectively lower the risk of SSIs. (51, 52) This risk is especially high in patients with poor glycemic control. Preventing SSIs in people with diabetes mellitus requires careful blood sugar control prior to, during, and following surgery. 1.5.5 Smoking Smoking impairs tissue oxygenation, immune system performance, and wound healing; it is a major risk factor for surgery site infections. Smokers compromised immune systems, the vasoconstrictive effects of nicotine, and the loss in oxygen delivery caused by carbon monoxide all raise the risk of SSI. Smokers are more vulnerable to having wound dehiscence, delayed healing, and bacterial colonization at surgical sites, all of which increase the risk of SSIs. Cessation of tobacco use before surgery can reduce these risks and enhance the results of the procedure as a whole (53). 13 1.5.6 Nutritional status Severe calorie-protein deficit characterized by more than two of the following traits: 1. noticeable, substantial muscular atrophy and loss of subcutaneous fat; 2. dietary intake that is less than 50% of the required amount for at least two weeks (as determined by the dietitian); 3. bedridden or with a markedly diminished ability to function; 4. Patients who lost more than 2% of their body weight in a week, 5% in a month, or 7.5% in three months had a considerably higher risk of SSI (54). Malnourished patients are more susceptible to infections due to impaired immune function, delayed wound healing, and compromised tissue integrity (55). Particularly insufficient protein intake can delay the process of wound healing by affecting collagen synthesis, angiogenesis, and fibroblast function (56). This highlights the importance of identifying and addressing severe protein-calorie deficiency in surgical patients to improve outcomes, so the nutritional state of a patient is also considered while determining ASA ratings (14). 1.5.7 Immunocompromised patient Patients who are immunocompromised are described as follows (57): 1. Congenital diseases (disorders of the T- or B-cells, dysfunctions of the macrophages, frequently in infants and adolescents but also in adults). 2. Acquired conditions: a. Affected by HIV infection and subsequently developing acquired immunodeficiency syndrome (AIDS). b. Hematologic cancer. c. Immunodeficient patients with intrinsic immunological diseases that fall under the category of "solid malignancy or solid organ transplanted patients or inflammatory disease/rheumatologic disease," as well as those who are receiving chemotherapy or immunomodulatory medications at the same time. d. Individuals with pathological or physiological conditions that include immunodeficiency of any kind. Deficiencies in Innate Immunity: The first line of defense against pathogens is the innate immune system. Phagocytic cells (such as neutrophils and macrophages) are frequently compromised in immunocompromised people, which lessens the body's 14 capacity to identify and eliminate infections. This raises the possibility of infection at the surgical site. SSIs are more common in immunocompromised patients because of their lowered immune systems and delayed wound healing. These people frequently have compromised innate and adaptive immune responses, which lessens the body's capacity to fend off infections. Chronic illnesses, immunosuppressive drugs, and inadequate nutrition all contribute to an increased risk of infection. To reduce SSI risks and enhance results in this susceptible population, preventive treatments such as perioperative antibiotics, nutritional and metabolic status optimization, and close post- surgery monitoring are crucial. 1.5.8 ASA score The American Society of Anesthesiologists created the ASA score to track the severity of a patient's underlying illness. The anesthesiologist’s inconsistencies in age and obesity ratings have been discovered to impact the accuracy of the ASA score in predicting SSI risk in elderly patients. This highlights the importance of considering multiple factors when assessing infection risk in this population (14). The definition of the ASA score is based on a scale of I to VI, with higher scores indicating more severe systemic disease: I: a patient in normal health II: Individual with a minor systemic illness III: A patient with severe systemic condition that is not incapacitating. IV: A patient with a life-threatening, incapacitating systemic condition V: Moribund patient, with or without surgery, who is not anticipated to live for 24 hours VI: A deceased individual who donates their organs. In clean-contaminated and dirty operations, the incidence of SSI was considerably greater in patients with (ASA) ratings II and II than in those with ASA score I. (58) The definition of the ASA score is based on a scale of I to VI, with higher scores indicating more severe systemic disease, as shown in Table 3. 15 Pre-operative procedure 1.5.9 Bathing with chlorhexidine before surgery Bathing using antibacterial chemicals like chlorhexidine before surgery has been found to minimize bacterial colonization on the skin (59). Several studies have looked into the effectiveness of preoperative showers, but few have conclusively proven that they reduce the incidence of SSI. A prospective, randomized clinical trial at six university-affiliated hospitals in the United States, between April 2004 and May 2008 compared chlorhexidine-alcohol use versus povidone-iodine for preoperative skin preparation and found that chlorhexidine- alcohol was more effective in preventing SSIs (60). Nevertheless, the World Health Organization (WHO) recommends bathing with chlorhexidine gluconate as a strategy to prevent SSIs, as it mentioned in its guidelines for the prevention of SSIs (61). 1.5.10 Hair removal If hair removal is absolutely necessary, then methods of hair removal prior to surgery are critical in preventing SSIs. It is better to use electric clippers to trim hair right before surgery rather than shaving with a razor since clipping minimizes the probability of skin irritation and microcuts, which can lead to an increased risk of infection. It's critical to adhere to sterile procedures when shaving hair in order to avoid contaminating the surgery site with microorganisms. Aseptic methods should be used for preoperative hair removal, in accordance with recommendations from the Centers for Disease Control and Prevention (CDC) and WHO (58). Intra-operative procedure 1.5.11 Normothermia and blood loss During the perioperative period, maintaining a temperature of 35.5°C or above is essential to prevent SSI. Even slight hypothermia can raise the risk of SSI. Hypothermia can either directly or indirectly decrease neutrophil activity by causing subcutaneous vasoconstriction and consequent tissue hypoxia. It can also increase blood loss by about 500 mL in surgical patients, resulting in wound hematomas or the requirement for transfusion, all of which can raise the risk of SSI. (62) Preoperative and intraoperative 16 warming have been demonstrated to reduce SSI rates and intraoperative blood loss in randomized controlled trials (63). 1.5.12 Type of surgical procedure When it comes to emergency surgeries, the risk of SSIs is much higher than it is for elective (planned) surgeries. These causes include patient condition, inadequate preoperative preparation, contamination concerns, and improper scheduling of antibiotic prophylaxis. The risk of SSIs is increased by the fact that emergency procedures are sometimes more complicated, involve compromised tissues, and are carried out in an urgent manner. Elective surgeries, on the other hand, have lower overall infection risk because of improved planning, patient optimization, and controlled surroundings (64). Many previous studies have pointed to higher infection rates in emergencies—23.8% compared to 7.4% for elective cases (65). This increase in SSIs during emergency procedures can often be traced back to shorter recovery times, limited preparation for both patients and surgeries, and the nature of certain injuries, like those from road traffic accidents. (64) For example, a study by Dessie et al. reported SSI rates of 38.3% for elective cases and 61.7% for emergencies, reinforcing this concern (66). When compared to open surgery, laparoscopic surgery often carries a lower risk of operative site infections. Laparoscopic operations have a lower risk of infection because they include smaller incisions, less tissue stress, and shorter hospital stays. However, there are increased chances for bacterial contamination and subsequent infection during open procedures due to their larger wounds and longer recuperation periods. While laparoscopic procedures, when practical, offer substantial benefits in lowering the risk of SSIs, open surgery may still be required in some complicated instances (67,68). 17 1.5.13 Wound classification. Four classes of wound status were defined by the CDC: (1, clean; 2, clean/ contaminated; 3, contaminated; and 4, dirty) (52). Postoperative risk of SSI for each class with scores of 1% to 5% for clean surgeries, 3% to 11% for clean-contaminated surgeries, 10% to 17% for contaminated surgeries, and more than 27% for dirty surgeries (69).  Class 1: clean wounds, these wounds are often closed, absent of inflammation and infection signs. If drainage is required, a closed draining approach is recommended. It is crucial to keep in mind that Class 1 wounds do not impact the respiratory, alimentary, vaginal, or urinary systems. Clean wounds include inguinal hernia surgery and thyroid  Class 2: clean-contaminated, suggesting a low level of contamination. Only under certain circumstances can these wounds enter the pulmonary, urinary, vaginal, or alimentary tracts.  Class 3: contaminated, typically the result of a gastrointestinal leak or a lapse in sterile protocols. Acute or non-purulent inflammatory incisions are also classified as Class 3 wounds.  Class 4: dirty or infected, these wounds are typically caused by obvious infections, excessive purulence, high purulence and inadequate traumatic wound care. Tissues that have lost their strength can cause class 4 wounds. This is usually caused by surgery or infections discovered in organs that have been pierced. (70) 1.5.14 Duration of operation The longer a surgery takes, the higher the chance of SSI because of things like increased bacterial colonization, prolonged tissue exposure, immune suppression from prolonged anesthesia, and longer hospital stays. Longer procedures are frequently more difficult and involve greater tissue stress, leading to delayed wound healing and a higher risk of infection. To reduce the incidence of SSIs during lengthy procedures, preventive measures such as maintaining normothermia, using appropriate antibiotic prophylaxis, and using efficient surgical techniques are crucial (71). 18 After the first 60 minutes of anesthesia, wound infection rates rise by 0.5% each minute. This means that for every extra hour of anesthesia, there is a 30% higher chance of postoperative infection (71). The mean duration of surgeries was 2.6 hours, with a median of 2.2 hours. So, we studied the possibility of infection at the study for a duration more than two hours. Post-operative procedure 1.5.15 Antibiotic prophylaxis The WHO provides comprehensive guidelines on antibiotic prophylaxis to reduce SSIs. The purpose of these guidelines is to encourage evidence-based procedures that maximize patient safety and reduce the possibility of SSIs. The main suggestions are to guarantee sufficient tissue levels at the time of surgery that provide the prophylactic antibiotics within 60 minutes of the surgical incision. Local epidemiology and susceptibility patterns should be taken into consideration when choosing antibiotics, with the goal of using narrow-spectrum medications to minimize collateral damage to normal flora and reduce the risk of resistance (61). Prophylactics should be administered for as short a period as possible, usually no more than 24 hours after surgery. Redosing antibiotics after the surgical incision is not recommended, unless the duration of surgery or significant blood loss necessitates additional doses. Adherence to national or local guidelines is essential, and surveillance systems should be in place to monitor adherence and track SSIs for quality improvement. These evidence-based recommendations promote appropriate antibiotic use, optimize patient safety, and support antimicrobial stewardship in surgical practice (61). Additionally, antibiotic prophylaxis is recommended for surgeries involving clean- contaminated or contaminated wounds to reduce the risk of SSIs, and it is justified in any surgical procedure involving an implant because it decreases the infection rate from 5% to 1%. These evidence-based recommendations are crucial for maximizing patient outcomes and encouraging antimicrobial stewardship in surgical settings (7). 19 The WHO guidelines emphasize the importance of a multidisciplinary approach involving surgeons, anesthesiologists, pharmacists, and infection prevention and control teams to guarantee appropriate antibiotic use and minimize the risk of SSIs. These evidence-based recommendations are crucial for maximizing patient outcomes and encouraging antimicrobial stewardship in surgical settings (61). 1.5.16 Remote site infection An infection that develops in a body area that is far from the location of a surgery or injury is referred to as a remote site infection. These infections can occur in a patient following surgery even if they have nothing to do with the surgical site or incision. In essence, the infection happens somewhere other than the actual surgery site, which is why it's called "remote." Pneumonia or urinary tract infections in patients who have had appendicectomies are examples of postoperative patient infections (72). Even though they happen in different places of the body, remote infections can occasionally be linked to SSIs. For instance:  Sepsis from a surgical wound's bacteremia (bloodstream infection) can impact distant organs.  Infections in distant locations, such as the heart (endocarditis) or bones (osteomyelitis), may become more likely following surgical procedures involving implants, devices, or prosthesis.  Systemic infections that impact other organs or tissues can result from surgical equipment contamination or from using inadequate aseptic procedures (73). Bloodstream infections, medical devices, or a compromised immune system following surgery may all lead to remote infections. Even if they have nothing to do with the actual surgery site, they could still make the patient's recovery more difficult. Depending on the patient's characteristics and the type of surgery, the exact prevalence of remote infections varies widely. For example: 1. In patients having major surgery, ventilator-associated pneumonia (VAP) is a common distant infection, especially if the patient is intubated or needs mechanical breathing. Although the risk is greater in critically sick patients, the incidence of VAP can vary from 10% to 30% in these situations (73,74). 20 2. Urinary tract infections linked to catheter use (CAUTIs): According to studies, 5– 10% of individuals who have urinary catheters in place for more than 48 hours get a UTI, which is a type of distant infection (73,74). 3. Sepsis (bloodstream infections) following surgery might affect 1–3% of patients overall, but it can be more common in high-risk surgeries (e.g., cardiac, gastrointestinal) (73). 4. Even though they are less common, other distant infections such osteomyelitis and endocarditis can nevertheless be significant in some patient groups (74). In summary, the occurrence of SSI is multifactorial, involving both intrinsic and extrinsic factors that makes their prevention and control a challenging task for any infection prevention and control program in any institution. To address therefore this preventable but yet very important event, a holistic approach is needed that addresses all these factors simultaneously to achieve the safest care possible for surgical patients. Table 1 and Table 2 summarized these factors and its pathophysiology. 21 Table 1 Summary of SSI risk factors and its pathophysiology”Intrinsic and Extrinsic factors“ Risk factor The pathophysiology. Intrinsic factors” non-modifiable patient-related risk factors” Age The immune system of older persons frequently deteriorates, making the body less effective at fighting illnesses, and reduced skin flexibility, hindering wound healing. Common comorbidities like diabetes and malnutrition further increase their susceptibility to SSIs. Gender Research suggests that women may have a slightly lower incidence of SSIs due to differences in body fat distribution and immune response. However, men might be at greater risk for certain surgeries, like heart procedures, due to higher comorbidity rates and lifestyle factors Extrinsic “Modifiable patient-related risk Obesity Excess body fat or obesity impairs healing by reducing blood flow and oxygen supply to tissues, increasing infection risk. Larger incisions and longer procedures associated with obesity further heighten susceptibility to infection and slow recovery from surgery. Diabetes High blood glucose damages blood vessels, reducing blood flow and nutrient delivery essential for healing, while also weakening the immune system. These factors, along with increased bacterial growth from elevated sugar levels, significantly raise the SSIs in diabetics. Smoking Smoking contributes to SSIs through a variety of mechanisms, including weakened immune systems, decreased oxygen transport to tissues, elevated inflammation, and changes in microbial ecology. Nutritional status SSI risk and outcomes can be strongly influenced by nutritional status. The body becomes more vulnerable to infection when its immune system is weakened and wounds are not healed properly due to inadequate nourishment. Immunocompr omised patient The body is less able to fight off infections when immunological responses are compromised. Immunosuppressive drugs, long-term illnesses, and inadequate nutrition all contribute to an increased risk of infection. 22 Table 2 Summary of SSI risk factors and its pathophysiology”pre-intra-post procedure“ Risk factor The pathophysiology. Pre-operative procedure Hair removal Hair removal before surgery can impact the risk of SSIs, with studies suggesting that clippers are safer than shaving, as shaving can create small skin incisions that promote bacterial growth. Intra-operative procedure Normothermia and blood loss Maintaining normothermia during surgery reduces the risk of SSIs by supporting immune function, enhancing tissue oxygenation, and promoting effective blood coagulation, all of which facilitate healing. Type of surgical procedure In general, SSIs are more likely to occur during emergency procedures because of increased contamination, weakened immune systems, and inadequate preoperative planning. Conversely, planned operations promote better patient optimization and reduce the risk of infection. Wound classification The risk of SSIs varies by wound classification, with clean wounds posing the least risk and filthy or infected wounds the highest, emphasizing the importance of proper surgical techniques, infection control, and patient optimization to reduce SSIs across all wound types. Duration of operation Longer surgery durations increase the risk SSIs due to greater bacterial exposure and tissue damage, making it crucial to minimize surgery time and maintain optimal patient conditions, such as normothermia, to reduce this risk. Post-operative procedure Antibiotic prophylaxis Antibiotic prophylaxis reduces bacterial colonization during surgery, which effectively lowers the incidence of SSIs. For best effects, time, dose, and antibiotic selection are crucial, and prudent use helps avoid antibiotic resistance. Remote site infection Remote site infections heighten the risk of SSIs by promoting bacterial growth and weakening the immune system, making it essential to treat these infections and enhance patient health before surgery to reduce SSI rates and improve outcomes. 23 1.6 Pathogens and patterns of resistance The patient's endogenous flora is the source of infection in most SSIs. The operating room environment, surgical personnel, and any tools, supplies, or equipment introduced into the sterile area are examples of exogenous causes of SSI. Aerobes, particularly gram-positive organisms like streptococci and staphylococci, make up the majority of external flora. Staphylococcus aureus is the species most frequently identified in the literature as causing SSI. (17). According to the CDC’s and (NHSN) Summary of Data, the most common pathogens were Staphylococcus aureus (16%), Enterococcus spp. 14%, Escherichia coli 12%, coagulase-negative staphylococci 11%, Candida spp. 9%, Klebsiella pneumoniae (and Klebsiella oxytoca; 8%, Pseudomonas aeruginosa 8%, and Enterobacter spp. 5% (75). From July 22 to October 25, 2016, a cross-sectional study was carried out in Ethiopia at Dessie Comprehensive Specialized Hospital (DCSH). S. aureus (n = 14; 66.67%) was the most common isolation among Gram-positive bacteria, followed by CoNS (n = 4; 19.05%). E. coli (9, 33.33%), Klebsiella species (7, 25.93%), and Citrobacter freundii (3, 11.11%) were the main organisms recovered as Gram-negative rods, which show at figure 4. 24 Figure 4 Pathogenic microorganism distribution among research participants with SSI at DCSH from July 22 to October 25, 2016 “Adapted from: Ali A, Gebretsadik D, Desta K. Incidence of surgical site infection, bacterial isolate, and their antimicrobial susceptibility pattern among patients who underwent surgery at Dessie Comprehensive Specialized Hospital, Northeast Ethiopia. SAGE Open Med. 2023 Jan 1;11” (76). According to a systemic review by Jouf University, Sakaka, Saudi Arabia, in 2022, 18 publications reported that Staphylococcus aureus, Klebsiella pneumonia, and E. coli were the three bacteria that were most frequently reported in the studies. In order to identify the epidemiological characteristics, incidence, etiological agents, and 25 predisposing risk factors for the development of postoperative infections among surgical patients across all six WHO regions, this systemic review was designed (77). 1.7 The significance of the study SSIs are still a major concern, as evidenced by several studies conducted around the world, despite surgeons' strict adherence to sterility and meticulous patient management before and after procedures (23). The Study on the efficacy of nosocomial infection control (SENIC) research in the United States looked into the effectiveness of measures to reduce hospital-associated infections. Infection rates were lowered by 32% in hospitals with effective programs. Organized surveillance and control efforts, an infection control physician, one infection control nurse per 250 beds, and a system for reporting infection rates to practicing surgeons were all part of the successful programs (78). NNUH has a similar evidence-based infection prevention program, which intended to protect its employees' and patients' health and safety. This program places a strong emphasis on maintaining good hygiene, regularly checking infection control measures, and providing continuous education regarding the significance of infection prevention. Additionally, the program raises awareness through training sessions and workshops, giving the hospital community the skills and knowledge, they need to recognize and reduce any infection risks. An-Najah National University Hospital aims to establish a secure and healthful learning environment by placing a high priority on infection prevention. NNUH is a tertiary teaching referral hospital with complicated cases, a JCI-certified hospital that has implemented a surveillance program using CDC methodology since 2020. The infection control program has a strong evidence-based structure that complies with WHO and CDC elements for a successful IPC program. SSIs present a significant challenge in the West Bank, as in many healthcare settings globally. Research indicates that the prevalence of SSIs in this region can be influenced by various factors, including surgical techniques, the conditions in healthcare facilities, and infection control practices (8). 26 The scarcity of studies in the region underscores the necessity for additional research to evaluate the specific risk factors leading to SSI in low- and middle-income countries as well as provide information about the efficacy of infection prevention initiatives. This research will be essential for informing healthcare professionals and policymakers and establishing a foundation for future targeted quality improvement programs and investigations. This study aims at determining the local incidence of SSI and its associated factors, as well as the most common causative species found in infected wounds, at the NNUH teaching referral university hospital in Nablus, Palestine. 1.8 Research Question What is the incidence of SSIs among patients admitted to NNUH for surgery and associated risk factors during 2018–2020? 1.9 Objectives 1.9.1 Main objective To determine the incidence of SSIs for patients admitted to surgery at NNUH, and associated risk factors during 2018–2020. 1.9.2 Specific Objectives 1. To assess the risk factors related to SSI at NNUH Hospital 2. To identify the SSIs' causative species. 27 Chapter Two Methodology 2.1 Study Design This is an analytical retrospective cohort study of all patients admitted for surgery between January 2018 and December 2020. 2.2 Study time, setting, and population The project focused on all patients undergoing surgery who need admission planned/elective or emergency at the wards and clinics of NNUH, a tertiary care teaching referral university hospital in Nablus, Palestine, with 123 beds in patients, 280 total beds, and two operating theaters with four operation rooms. Patients are usually seen in outpatient clinics, and those who are scheduled for surgery will be included in the study. Those who fulfill the inclusion criteria were enrolled on the day of admission, followed up in the hospital after surgery, and then followed up with clinic visits until the completion of the study period. Infection presents at the time of surgery, and eligible procedures that are assigned an ASA score of 6 are not eligible for SSI surveillance. • Numerator: SSI event clinically reported by positive culture or by patient based on specific criteria • Denominator: data on all procedures included in the selected operative procedure categories 2.3 Inclusion’s criteria 1. Inpatient surgeries. 2. Adult patient (age ≥ 18 years) who underwent either elective or emergency surgery. 3. Patient who underwent general, cardiac, orthopedic, and vascular surgeries. 2.4 Exclusion’s criteria 1. Day case surgeries. 2. Any patients who, at the time of surgery, have a skin or soft tissue infection. 3. Any patient who has had surgery at another hospital on the same site in the last 30 days. 28 2.5 Sample size calculation The minimum sample size desired to achieve a confidence level of 95%, an estimated margin of error of 5%, assuming a large population and using a size effect of 12%, was calculated using the above equation: n= Z2 *p* (1-p)/E2 (1) Where, n= Sample size Z = z score corresponding to level of confidence of 95% = 1.96 p = percentage of population = 0.12 E = margin of error = 5% Therefore, the minimal sample size would be 163 patients. Since it is a retrospective study and the data is already available, with no opportunity of loss of follow up during the period of observation, the calculation of sample size using proportion will not require adjustments for loss of follow-up. Nevertheless, in this study, all patients who met the inclusion criteria were included, accounting for 1157 patients. The final sample size during the study duration was 1157 patients. 2.6 Study variables The presence or absence of SSI (binary outcome) was the dependent variable in this study. The independent variables that were investigated were as follows: Gender (male and female), age (in years), duration of surgery (in hours), surgical wound classification (clean, clean-contaminated, contaminated, or dirty/infected), the ASA index (ASA I, ASA II, ASA III, or ASA IV/V), emergency surgery (yes/no), and diabetes mellitus (DM) (yes/no), smoking status (yes or no), as shown in Table 3. 29 Table 3 The independent variable, operational definition, and the type of measurement The variable Operational Definition Type of measurement Age Age at time of surgery in years (continuous) Duration of operation The time from the skin incision to skin closure Continuous in hours. Type of operation A planned operation was recorded as an elective procedure for the patient. There was no emergency operation planned. Elective/emergency. Obesity Body mass index (BMI) of 30 or greater Yes, No American Society of Anesthesiologists physical status classification (ASA) The anesthesiologist's score based on the ASA scoring system I: a patient in normal health II: Individual with a minor systemic illness III: A patient with severe systemic condition that is not incapacitating. IV: A patient with a life- threatening, incapacitating systemic condition V: Moribund patient, with or without surgery, who is not anticipated to live for 24 hours VI: A deceased individual who donates their organs. Wound classification The surgeon's score in accordance with the wound categorization system 1.Clean wounds 2. Clean-Contaminated wounds 3.Contaminated wounds 4. Dirty or infected wounds. Antibiotic prophylaxes A patient should be considered to be receiving prophylaxis if; 1. Antibiotics are administered either 24 hours before or 24 hours after surgery. 2. When using antibiotics, there is no history of fever or infections. Yes, No Post-operative glucose Maintain blood glucose level after surgery less than 180 mg/dl Yes, No Post-operative normothermia Maintain temperature between 36.1-37.1 Yes, No.0 + 30 The following variables: bathing with chlorhexidine before surgery, hair removal, and blood loss, also reported in the literature as potential risk factors for the development of SSI, were not considered due to difficulties in data availability and gathering in a retrospective study. 2.7 Duration of follow-up Both patients who had elective or urgent operations were monitored for 30 to 90 days afterward. According to the CDC, a superficial or deep SSI is described as an infection that occurs within 30 to 90 days of a surgical procedure. The follow up was done by either subsequent visits to the clinic after surgery and/or a phone call to ask about signs and symptoms and if they had visited another doctor for any symptom. The follow up included also all reports received from doctors notifying the occurrence of infection as per hospital protocol. 2.8 Data collection Patient information from the patient's file was used to gather data for the datasheets "case report form of surgical producer denominator's, prevention of surgical site infection. (Appendix 1)." The data sheets were kept safe and confidential at the researcher's office. At the conclusion of the report, all data introduced into Excel sheets for easy review by the researcher. 2.9 Data analysis After data was entered in excel sheet, depurated and completed, descriptive analysis was performed according to the type of variable: categorical ones using frequencies and percentages while continuous variables were analyzed using mean and standard deviation (SD). Further analytical analysis using an appropriate test: chi-square test, Fisher exact test, or t-test Analysis of Variance test (ANOVA) were applied to study the possible association between sociodemographic characteristics as well as the clinical characteristics of patients or surgery characteristics and the development of SSIs. The level of significance used was 5% (p-value < 0.05). 31 As the outcome considered in this study is a binary one: SSI (yes, no), a binary logistic regression has been performed to predict the potential development of SSI given the mentioned risk factors. Odds Ratios and their respective 95% Confidence Interval (95%CI) were reported. IBM SPSS (Statistical Package for the Social Sciences) Version;21 was used to analyze the data. 2.10 Ethical Considerations To ensure that the study meets the Declaration of Helsinki ethical principles, permission to perform the study was obtained from the Institutional Review Board (IRB) at (Ref: Mas.April.2022/11). In addition, the appropriate administrative approvals from the Hospital Research Center and the hospital were retrieved. Confidentiality of data was ensured by the anonymization of the data and removal of potential sensitive identifiers. The researcher was the only person having access to the data. 32 Chapter Three Result 3.1 The result of the study The study involved 1,157 patients who underwent surgical procedures between 2018 and 2020 at NNUH. During the period of the study, the overall incidence of SSI in this study was 7.65%. In 2018, the incidence was 18.2%, which dropped to 6.6% in 2019 and further to 0.6% in 2020, as illustrated in Figure 5, showing a consistent decline in incidence over the years. Figure 5 Surgical site infection rate at NNUH 2018-2020 Among study participants, 675 (58.3%) were male, with an age of 50.2 years (SD 17.8). Regarding the sociodemographic and clinical characteristics of participants, 296 (25.9%) were current smokers, 54 (4.9%) had a history of trauma, and 490 (42.3%) had diabetes, while 31 (3.3%) were classified as normally healthy according to the ASA classification. Additionally, 60 (5.3%) patients had malnutrition, while 83 (7.2%) were immunocompromised. Obesity was present in 103 (9.3%) of the participants, and 18.20 6.60 0.60 2018 2019 2020 33 prosthesis placement was reported in 75 (6.8%) of the study population. Table 4, summarizes the baseline characteristics of the study population. Table 4 Sociodemographic and clinical characteristics of study participants. (N=1157) Variable n % Age group (years) ≤30 31-50 51-70 ≥71 230 292 488 147 19.9 25.2 42.3 12.4 Gender Male 675 58.3 Female 482 41.7 Malnutrition Yes 60 5.3 No 1074 94.7 Missing 23 2.0 Obesity Yes 103 9.3 No 1010 90.7 Missing 44 3.8 Diabetes Mellitus Yes 490 42.3 No 661 57.4 Missing 6 0.5 ASA score I: a patient in normal health 31 3.3 II: Individual with a minor systemic illness 482 50.6 III: A patient with severe systemic condition that is not incapacitating. 406 42.6 IV: A patient with a life-threatening, incapacitating systemic condition 34 3.6 Missing 204 17.6 Smoker Yes 296 25.9 No 849 74.1 Missing 12 1.0 Immunocompromised Yes 83 7.2 No 1067 92.8 Missing 7 0.6 Trauma Yes 54 4.9 No 1039 95.1 Missed 64 5.5 Prosthesis placement Yes 75 6.8 No 1020 93.2 Missed 62 5.4 34 The mean duration of the length of stay was 8.06 (11.9), and the most common type of surgery was programmed for 1096 (94.7%) patients, making up the majority of procedures performed. Notably, 1,036 (90.8%) received antimicrobial prophylaxis within 24 hours after surgery, while patients with postoperative blood glucose control of less than 180 mg/dL had 92 % of cases. Additionally, maintaining a temperature post-surgery between 35.5 °C and 36.5 °C also helps reduce the risk of infection, with a total of 93.3% fulfilling these criteria. The most common surgical category was general surgery, accounting for 491 (42.5%) of all cases. These procedure-related characteristics of the patient are presented in Table 5. 35 Table 5 Procedure -related characteristics of the patients (N:1157) Risk factor n % Type of surgical procedure (Access) Laparoscopic 168 15.1 non-laparoscopic 944 84.9 Missed 45 3.9 Type of surgery Emergency 61 5.3 Programmed 1096 94.7 Missed 2 0.2 Duration of procedure <2 hours 498 43.0 ≥2 hours 659 57.0 Surgical wound classification Clean 963 90.87 Clean-contaminated 80 7.5 Contaminated 18 1.7 Missed 96 8.3 Antimicrobial prophylaxis within24 after surgery Yes 1036 90.8 No 105 9.2 Missed 16 1.4 Postoperative blood glucose control Yes 1016 92.0 No 88 8.0 Missed 53 4.6 Temperature post-surgery Yes 1030 93.3 No 74 6.7 Missed 53 4.6 Surgical category General surgery 491 42.4 Cardiac surgery 244 21.1 Orthopedic surgery 228 19.7 Vascular surgery 193 16.7 Overall, there were (90) 7.65% cases of SSI identified in this study. SSI was more prevalent in male than in female (8.9% vs. 6.2%). Contaminated wounds had the highest rate of SSIs 44.4%, followed by clean-contaminated 18.8% and clean 6.9% wounds (p<0.001). SSIs were more prevalent in non-laparoscopic surgeries (p < 0.02), longer-duration procedures (p < 0.001), and patients with prothesis implantation (p = 0.03). 36 Among those with an ASA index of IV or higher, the incidence of SSIs was 14.7% (p<0.001). All characteristics are shown in Table 6 and Table 7. Table 6 Intrinsic and extrinsic factors distribution of the study population per SSI (n = 1157) Variable SSI Yes No P-value Gender Male 60 (8.9%) 615(91.1%) 0.095 Female 30 (6.2%) 452(93.8%) Age ≤30 28 (12.2%) 202(87.8%) 31-50 15 (5.1) % 277(94.9%) 51-70 33(6.8%) 455(93.2%) 0.019 ≥71 14(10.2%) 133(91.1%) Malnutrition Yes 3(5%) 57(95%) 0.29* No 86(8%) 988(92%) Obesity Yes 9(8.7%) 94(91.3%) 0.77 No 80(7.9%) 930(92.1%) Diabetes Mellitus Yes 35(7.1%) 455(92.9%) 0.46 No 55(8.3%) 606(91.7%) ASA score I: a patient in normal health 2(6.5%) 29(93.5%) II: Individual with a minor systemic illness 21(4.4%) 461(95.6) III: A patient with severe systemic condition that is not incapacitating. 37(9.1%) 369(90.9%) 0.01 IV: A patient with a life- threatening, incapacitating systemic condition 5(14.7%) 29(85.3%) Smoker Yes 24(8.1%) 272(91.9%) 0.85 No 66(7.8%) 783(92.2%) Immunocompromised Yes 2(2.4%) 81(97.6%) 0.056 No 88(8.2%) 979(91.8%) Remote site infections Yes 2(11.8%) 15(88.2%) 0.53 No 87(7.7%) 1044(92.3%) 37 Table 7 Producer-risk factor distribution of the study population per SSI (n = 1157) Prosthesis placement Yes 11(14.7%) 64(85.3%) 0.03 No 79(7.7%) 941(92.3%) Type of surgical procedure (Access) Laparoscopic 6(3.6%) 162(96.4%) 0.020 non-laparoscopic 84(8.9%) 860(91.1%) Type of surgery Emergency 6(9.8%) 55(90.2%) 0.53 Programmed 84(7.7%) 1012(92.3%) Duration of procedure <2 hours 26(5.2%) 472(94.8%) <0.001 ≥2 hours 64(9.7%) 595(90.3%) Surgical wound classification Clean 66(6.9%) 897(93.1%) Clean-contaminated 15(18.8%) 65(81.3%) <0.001 Contaminated 8(44.4%) 10(55.6%) Antimicrobial prophylaxis within24 after surgery Yes 61(5.9%) 975(94.1%) <0.001 No 28(26.7%) 77(73.3%) Postoperative blood glucose control Yes 70(6.9%) 946(93.1%) <0.001 No 19(21.6%) 69(78.4%) Temperature post-surgery Yes 70(6.8%) 960(93.2%) <0.001 No 19(25.7%) 55(74.3%) Surgical category General surgery 35(7.1%) 456(92.9%) Cardiac surgery 29(11.9%) 215(88.1%) 0.08 Orthopedic surgery 16(7%) 212(93%) Vascular surgery 10(5.2%) 183(94.8%) SSI: Surgical site infection. P-value: Chi-square test. *P-value: Fisher's exact test SSIs incidence rates by type of surgery, among cardiac surgery 11.9% had SSI, general surgery 7.1% had SSI, while among orthopedic surgery 7%, and vascular surgery 5.2% had SSI. 38 General surgery was the most prevalent surgery performed during the period of the study, with total number of general surgeries is 491, of which 15 (44.1%) had superficial SSIs, while 17 (47.2%) had deep SSIs. Cardiac surgery accounting for a total of 244 surgeries, with 8 (23.5%) having superficial SSIs, 10 (27.2%) having deep SSIs, and none having organ SSIs. Orthopedic surgery had a total of 228 surgeries, with 8 (23.5%) having superficial SSIs, 4 (11.1%) having deep SSIs, and one (100%) having organ/space SSIs. The vascular surgery as well as general surgery both did not present any case with SSI involving deep organs. In fact, out of 193 surgeries, only 3 (8.8%) were reported as superficial SSIs and 5 (13.9%) had deep SSIs. as illustrated in Figure 6 Figure 6 The incidence of SSIs. The number of surgeries and surgical site infections (SSIs) for each category are shown in the bar chart Overall, the data shows that cardiac surgery had the highest percentage of deep SSIs compared to orthopedic and vascular surgery Table 8. 491 244 228 193 38.90% 32.20% 18% 5.20% 100% 100% General surgery Cardiac surgery Orthopedic surgery Vascular surgery Surgical site infection rate by type of procedure Total of surgeries SSI (%) 39 Table 8 Incidence of SSI based on the surgical type of infection Surgical site infection rate by surgical type of infection Surgical procedure (n) Type of infection SIP DIP Organ General surgery (491) 15(44.1%) 17(47.2%) 0(0.0%) Cardiac surgery (244) 8(23.5%) 10(27.8%) 0(0.0%) Orthopedic surgery (228) 8(23.5%) 4(11.1%) 1(100%) A total of 77 pathogens were isolated. The most common organism found based on tissue and/or wound cultures was Klebsiella pneumoniae, followed closely by Acinetobacter baumannii and Escherichia coli., as presented in Table 9. 40 Table 9 Most common pathogen total N: 77 Most common pathogen total N:77 Type of micro-organism No. specimens Percentage Staphylococcus epidermidis 11 14.3% Klebsiella pneumoniae 14 18.2% Acinetobacter baumannii 12 15.6% Pseudomonas aeruginosa 3 3.9% Escherichia coli 11 14.3% Staphylococcus warneri 1 1.3% Enterococcus faecium 6 7.8% pseudomonas putida 1 1.3% Enterococcus faecalis 4 5.2% Enterococcus avium 1 1.3% Methicillin-resistant staphylococcus aureus (MRSA) 1 1.3% Staphylococcus aureus 5 6.5% Enterobacter cloacae complex 1 1.3% Bacteroides fragilis 1 1.3% Candida albicans 1 1.3% Citrobacter 1 1.3% Pseudomonas stutzeri 1 1.3% Citrobacter freundii 1 1.3% Stenotrophomonas 1 1.3% The overall mortality rate among all patients was approximately 16 (11.38%). However, among patients who developed surgical site infections (SSIs), the mortality rate was significantly lower at 3 (0.25%). Further analysis is necessary to identify the specific causes of death and any potential patterns. It is important to closely examine the patient index for those who experienced mortality with SSIs to uncover common factors that 41 may have contributed to their outcomes. This information will be valuable for informing future treatment strategies and interventions aimed at improving patient outcomes. A binary logistic regression was performed to assess potential variables that predict the occurrence of SSI among our patients. The variables included in the model were the following, based on previous research and clinical expertise: smoking status, immunosuppression, RSI, duration of the procedure, presence of a prosthesis, wound classification, post-operative glucose levels, post- operative temperature, days of stay (DOSS), wound site, significant post-operative symptoms, and type of infection. The model explained 68.5% (Nagelkerke R2) of the variance in SSI and correctly classified 92.5 % of the cases. 3.2 Odds ratios for significant variables The odds ratios provide detailed information about the impact of different variables on the likelihood of developing SSI. Based on the logistic regression performed, surgeries with longer durations (2 hours or more) are approximately 17 times more likely to result in an SSI (p<0.001), patients with a prosthesis are 9 times more likely to develop SSI compared with those who do not have a prothesis or implant (p = 0.002), and contaminated wounds are 23 times more likely to lead to an infection (p = 0.005). Moreover, each additional day a patient stays in the hospital increases the odds of developing an SSI by 4.6%. While the effect size is smaller compared to other variables, it indicates a cumulative risk. All mentioned variables were statistically significant, as shown in Table 10. 42 Table 10 Multivariate analysis of risk factors associated with surgical site infection Variables OR 95%CI P value Duration of procedure (< 2hours*) ≥2hours 17.71 3.71- 124.01 <0.001 Prothesis (No*) Yes 9.15 2.12 – 37.33 0.002 Wound classification (Clean wound*) Contaminated wound 22.91 2.44 – 214.17 0.005 Days of stay (in days) 1.046 1.02 - 1.07 <0.001 OR= Odds Ratio; 95%CI= Confidence interval 95%; p value significant at 0.05; (*) = Reference category 43 Chapter Four Discussion of Results 4.1 Discussion This study looked at the occurrence of SSI in 1,157 patients admitted to a major referral teaching hospital in the North of the West Bank between 2018 and 2020 and explored the factors linked to it. We found that 7.65% of patients (90 individuals) developed an SSI during this period. Fortunately, the rate has been declining over the years, mainly due to the implementation of a strong surveillance program using the CDC methodology and enforcement of all evidence-based infection and prevention elements suggested by the WHO program. Those results are therefore reflecting a better management of risk factors leading to SSI in our health setting, impacting positively patient outcomes and the quality of healthcare provided. It is important to highlight that the incidence rate in our institution, although high at baseline assessment 18%, has significantly dropped over the years and is even better than the reported in the region, such as in Saudi Arabia, where the incidence was of 12% in 2016. (79) The 7.8% is even similar to those reported in studies performed in high income countries (23). It’s also important to mention that the period of study include pandemic (COVID-19), the pandemic has underscored the importance of stringent infection control measures and careful monitoring of surgical patients to minimize the risk of SSIs. A study conducted at 2023 to evaluated how the COVID-19 pandemic affected surgical site infections (SSIs) in several surgical specialties, data collected by American College of Surgeons National Surgical Quality Improvement Program. Researchers compared two cohorts, Cohort A (pre-pandemic, N = 24,060) and Cohort B (pandemic, N = 3,698), using data from the American College of Surgeons National Surgical Quality Improvement Program from January 1, 2015, to April 1, 2021. With rates of 2.8% in Cohort B against 4.5% in Cohort A, the findings showed a decrease in the overall incidence of SSI during the pandemic (p < 0.001). Prior to the pandemic, multivariable analysis revealed a declining trend in SSIs, which continued to decline by 39% at the start of the epidemic (80). 44 The study concludes that although overall SSI incidence decreased, the most noticeable effect was seen in general surgical patients, indicating a positive influence of enhanced infection control measures, known as the "COVID bundle," on SSI rates. Notably, SSI rates trended downward significantly in general surgical patients at the beginning of the pandemic (80). Our findings also showed that patients over the age of 70 year were more likely to develop SSIs. Many of these individuals had underlying health conditions like diabetes or other co-morbid diseases, which can weaken the immune system and make them more susceptible to infections. This trend aligns with previous research, such as the studies conducted by Owens et al. (81) and Bharatnur et al. (82) ,which also found that older age groups—particularly those between 36 and 50—had a higher risk of SSIs compared to the younger individuals. In our study, we found that males had a higher rate of SSIs 8.9% compared to females 6.2%, though this difference wasn’t statistically significant. This mirrors findings from a 2005 study in Peru, where Hernandez et al. also reported that men experienced more SSIs 65.6% (83). Also, the results from the German National Nosocomial Infections Surveillance System that analyzed more than 438,050 surgical procedures showed that there are gender differences in the occurrence of SSI, as males were more prone to have a weaker immune system, to have skin colonization, more comorbidities, and even present higher infection rates after certain surgeries (84,85). Obesity is a significant risk factor for developing SSIs, as highlighted by numerous studies. The increased risk is largely attributed to greater tissue trauma, impaired wound healing, and the presence of other health issues, such as diabetes, that are common in obese patients (50, 81). In our study, 9 of the 90 patients with SSIs 8.7% were obese, while the majority 7.9% were not. This may be due to the fact that more non-obese patients underwent surgeries, and it’s worth noting that BMI data was missing for about 44 patients, which is a limitation of our findings. Research from the Dutch national surveillance network PREZIES indicates that the risk of SSIs rises steadily as BMI increases, from normal weight to morbid obesity. This underscores the need to pay closer attention to SSI risks in overweight and obese individuals and highlights the importance of addressing obesity at the community level (86). 45 Patients with comorbidities exhibit an elevated risk of SSIs relative to those without such conditions. Diabetes mellitus, although a known risk factor for the development of SSI as it interferes with wound healing and weakens immunity was not identified as such in our study. This contrasts with a study by Mohan et al. from Trichy, Tamil Nadu, India, which reported a higher rate of SSIs among diabetics, approaching 50% (87). Similarly, currently smoking was not found to be statistically significant in our study. In fact, 26.7% of smokers developed SSIs, which is a considerable proportion but this wasn't statistically significant. This contrasts with other research that has clearly shown smoking as a major risk factor for infections. For example, a study by Sorensen et al. (88) found that smokers were 2-3 times more likely to develop wound infections, while Hawn et al. also reported a much higher infection rate among smokers compared to non- smokers (89). The difference between our findings and those studies could be due to several factors, like the smaller sample size or the fact that other risk factors, like the patient’s overall health or the type of surgery, may have played a bigger role in our cases. Despite the fact that our results have not shown a statistically significant association with the increased risk of developing SSI, both factors are still recognized by most available research as plausible risk factors and therefore are elements included in our surveillance system. Patients with a higher ASA index were found to have a greater incidence of SSIs, which was statistically significant. Several studies have identified the ASA index as a significant risk factor for these infections, likely due to the fact that elevated ASA scores reflect an increased severity of systemic disease and comorbidities, potentially impairing immune response and wound healing (58,90). In our study, 1,157 patients underwent a variety of surgeries. Among them, 38.9% (491 patients) had general procedures like appendectomies, hernia repair, and exploratory laparotomies. Orthopedic surgeries, such as open reduction and internal fixation (ORIF) and hip or knee replacements, were performed on 228 patients, with 17.8% of those developing SSIs. Additionally, 193 patients 11.1% had vascular surgeries, and (244) 32.2% underwent cardiac procedures. 46 When looking at abdominal surgeries, our study also echoes findings from a systematic review and meta-analysis, which showed that SSI rates are higher in low- and middle- income countries—23.2% and 14%, respectively—compared to 9.4% in high-income countries. These surgeries tend to have higher infection rates overall, with reported rates ranging from 3.0% to 58.2%, highlighting the importance of improving infection prevention in these procedures across different healthcare settings (91). A recent study in India shows that abdominal surgery has the highest SSI rates among all surgical procedures (92). Patients who have cardiac surgery are especially vulnerable to SSI and hospital infections, which lead to extra procedures and higher expenses for the hospital. The mortality rate from these causes can exceed 25%, while SSI rates can range from 3.5% to 21%. Longer operating times, invasive procedures like sternotomies, and common patient comorbidities like diabetes and obesity are all variables that raise the risk of SSIs following cardiac surgery (93). These findings are consistent with other researches. For instance, a 2019 study published in 2015 by Andrew J. et al. found that orthopedic surgeries, particularly joint replacements, have a higher risk of SSIs. Factors like the use of implants, longer surgeries, and underlying health conditions in patients all contribute to this increased risk (94). Similarly, a study by Maksimović et al. conducted at the teaching hospital in Belgrade in 2007 found that orthopedic procedures were more frequently associated with SSIs, especially when prosthetic devices were involved (95). We looked at 1,096 elective procedures and 61 emergency procedures, finding that (84) 7.1% of the elective surgeries and (6) 3.6% of the emergency surgeries resulted in SSIs. While the analysis showed that the risk of SSIs from emergency surgeries was not statistically significant (p = 0.53). If SSIs are higher in elective surgeries compared to emergency procedures, several factors may explain this. Elective surgery numbers in our settings are relatively low compared to the programmed ones, which may have affected the results. Besides, they often involve more complex procedures and longer operation times, increasing infection risk. Additionally, patients undergoing elective surgeries may have underlying health issues that are less common in emergency cases. The surgical techniques used can also 47 differ, and elective patients typically spend more time in the hospital, potentially increasing exposure to infections. These factors underscore the need for tailored infection prevention strategies for both types of surgeries. When comparing laparoscopic and open surgeries, open procedures showed a higher risk of SSIs, which was found in our study to be statistically significant. This aligns with previous research. Laparoscopic surgery often involves less exposure to the external environment, reduced immune system impact, the use of carbon dioxide pneumoperitoneum, and better visibility for dissection and hemostasis, all of which may contribute to a lower occurrence of SSIs (67, 68). When moving from clean to dirty wound operations, a trend toward increased rates of postoperative SSIs was seen. (52,53,70) However, the postoperative SSI rate at our study for the clean, clean/contaminated, and contaminated wound classes was 6.9%, 18.8%, 44.44 respectively which consistent with other studies. According to a 2019 systematic review and meta-analysis, SSI was much more common in clean and clean- contaminated procedures across a wide range of developing-nation countries. In every country examined, the prevalence of SSI in elective clean and clean-contaminated procedures was 6% (95% CI 5–7%) (96). In fact, in our study, we found that longer surgeries (> 2 hours) were linked to a higher incidence of SSIs. A Brazilian study from 2017 reported that the risk of developing an SSI increased by 34% for each additional hour of surgery after the first hour. (97) Similar patterns have been observed in developed countries like France (90) and Italy. (98) Cheng et al. provided insights, as mentioned before, into why this might be the case, explaining that extended surgical times expose wounds to the environment for longer, which raises the risk of infection. Additionally, longer procedures can lead to dryness around incisions, and the effectiveness of prophylactic antibiotics may diminish over time, especially if the dose isn’t repeated. All of these factors together contribute to a greater risk of SSIs (71). Additionally, managing postoperative blood glucose levels and temperature is crucial for further reducing the risk of SSIs. Our data showed a strong relationship between these factors and the development of infections, with 19 cases 21.6% of SSIs linked to 48 poor management of blood glucose; the results were statistically significant (p<0.001) (52). On the other hand, antimicrobial prophylaxis played a significant role in reducing the incidence of SSIs, with 28 cases 26.7% recorded. However, unnecessarily prolonged use of antibiotics can lead to issues like superinfections (such as Clostridium difficile), increased antimicrobial resistance, longer hospital stays, and higher medical costs (7). Hence, targeted antimicrobial prophylaxis can play a key role in reducing the incidence of SSIs while avoiding the risks associated with unnecessary prolonged antibiotic use, such as superinfections and antimicrobial resistance. It is also important to focus on managing postoperative blood glucose levels and temperature, as these factors have a strong connection to the development of infections. In our institution, all mentioned parameters are within the protocol of SSI prevention and control and are managed according to WHO recommendations. Besides, the implementation of the antibiotic stewardship program in the hospital since 2020 is also contributing to the follow up of the antibiotic prophylaxis during and after the surgical procedures performed. The microbiological analysis of infected tissues and/or wounds revealed that Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli were the most common pathogens, which aligns with findings from similar studies that point to the significance of superficial infections (75). Acinetobacter baumannii also stood out as the second most prevalent microorganism at NNUH hospital, raising concerns given that our setting is a tertiary referral hospital in a region where multidrug-resistant organisms (MDROs) are common (99). The International Wound Journal article by Rose A. Cooper et al. emphasizes the microbiological and epidemiological components of SSIs in orthopedic and trauma surgery (100). It could have, however, covered opportunistic fungi implicated in SSIs in greater detail (100). The incidence of fungal surgical site infections (SSIs) in intensive care units is 4/1000 admissions, according to data from Kasturba Hospital in Manipal, Karnataka. Common pathogens include Candida albicans, Candida tropicalis, Candida glabrata, and Rhodotorula glutinis, while environmental molds include Aspergillus flavus and Fusarium solani (100). 49 While bacterial infections dominate, Candida infections should also be considered, particularly in immunocompromised patients, as these fungi can readily colonize and invade when the skin barrier is impaired (101). The article also discusses how treatment choices are made more difficult by the evolution of azole resistance in Candida species, namely as a result of C. glabrata's altered ERG11 gene. It might be required to use alternative treatments such liposomal amphotericin B. Additionally, prosthetic devices are at danger because to Candida species' capacity to produce biofilms (101). The logistic regression results showed a clear connection between higher risks SSIs and factors like longer procedures (over two hours), contaminated wounds, the use of prostheses, and longer hospital stays. Each of these factors significantly increases the chance of developing an infection, reinforcing what other studies have also found. This emphasizes the importance of addressing these risks during surgery and focusing on reducing hospital stays after surgery to help lower the chance of infections in our patients. This situation emphasizes the need for continues enforcement of effective infection control protocols and focused antimicrobial treatments, as research shows that mismanagement of these pathogens can lead to in