Comparison of the Distribution of Type III Exotoxin-Encoding Genes and Antibiotic Resistance Between Environmental and Clinical Pseudomonas aeruginosa Isolates in Northern West Bank-Palestine
Pseudomonas aeruginosa isolate is capable of producing certain virulence factors, expression of these virulence factors in a specific infection plays an essential role in the ability of this pathogen to establish and maintain infection. A total of 57 P. aeruginosa isolates were collected from different sources of clinical (n=47) and environmental samples (n=10) during 2018. These samples were collected from different health care centers, North West Bank-Palestine. This study aimed to compare the distribution of the type III exotoxin-encoding genes and antibiotic resistance between P. aeruginosa strains that were isolated from both sources, and to determine the presence of a correlation between them in both clinical and environmental isolates collected from a limited geographical area, in parallel, over a limited period of time. In addition, clone identity among the clinical and environmental strains was determined and compared using molecular typing technique. Results of this study showed that isolates recovered from clinical and environmental sources showed high resistant to Tetracycline and Kanamycin. Results of the current research using multiplex PCR technique showed that all clinical and environmental P. aeruginosa isolates carried type III secretion toxins-encoding genes. The exoT gene was detected among all clinical and environmental isolates. The occurrence of exoY and exoS genes in P. aeruginosa isolates from both sources was 80.7% and 36.8%, respectively. Combination of the toxin genes was noted in 87% of clinical and 70% of environmental isolates. The most common combination was exoT and Y, the prevalence was 47% and 50% for clinical and environmental isolates, respectively. The exoU gene was not detected in isolates from both sources. Statistical analysis using Pearson Chi-Square test showed that there is no significant difference between the distribution type III secretion toxins-encoding genes and source of isolate (clinical or enivironmental). In addition, statistical analysis indicated that there was not a significant association between P. aeruginosa isolates type III exotoxin-encoding genes and resistant to some antibiotics such as Ciprofloxacin, Norfloxacin, Levofloxacin, Aztreonam, Tetracycline and Kanamycin. The profile of RAPD-PCR typing of 44 P. aeruginosa isolates (9 environmental recovered from different hospital sinks and 35 clinical isolates recovered from different hospitals were clustered into 3 clusters at 96% similarity level. Cluster-1 and cluster-2 had strains recovered from different hospitals and belonged to both environmental and clinical sources. Cluster-3 had identical RAPD-PCR profile strains, recovered from clinical sources only from different hospitals. In addition, statistical analysis showed that there was no significant difference between strains isolated from both environmental and clinical sources according to antibiotic resistance and occurrence of type III secretion toxins-encoding genes. In conclusion, according to RAPD-PCR typing there is a high similarity between environmental and clinical P. aeruginosa isolates. In addition, isolates from both sources had no significant differences in antibiotic resistance and distribution of type III secretion toxins-encoding genes. This may indicate that isolates from both sources have ability to cause clinical infection.