Prevalence and Characterization of Staphylococcus aureus Isolated from Bulk Tank Milk Dairy Cow Farms in West Bank-Palestine
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An-Najah National University
The emergence of Methicillin-resistant Staphylococcus aureus (MRSA) in cattle is considered one of the major public health problem. The current study aimed to characterize and document the prevalence and distribution of MSSA (Methicillin-sensitive Staphylococcus) and MRSA in bulk tank milk samples (BTM), antibiotic resistance rate, and genetic characterization of clones for both MSSA and MRSA using ERIC-PCR and spA typing. In addition, to evaluate the occurrence of MRSA in human workers in these cow dairy farms and in the environment of these farms, this will provide useful data for epidemiological studies. A total of 57 bovine BTM samples, 45 dust samples from the environmental surfaces and 16 nasal swabs from the human workers in these farms were collected from 12 bovine diary farms in Jenin district in northern West Bank-Palestine, between September and October, 2017. A total of 251 of S. aureus isolates were recovered from all samples, which were 136 (54.2%) isolates detected from bulk tank milk samples, 35 (14%) isolates from nasal human workers and 80 (31.8%) isolates recovered from environment sources. Only 68 of S. aureus isolates were tested for antibiotic resistance, 39 isolates were from BTM samples, 10 isolates were from human workers nasal swabs and 19 isolates from environment sources. Results showed that 58.3% (7/12) of farms had at least one BTM sample contaminated with MRSA. In addition, S. aureus in this study was detected in 68.4% bovine BTM samples, while MRSA was detected in 45.6% of bovine BTM samples. Staphylococcus aureus recovered from BTM samples, environment sources and nasal human workers had a high level of resistance against many different antibiotics. Results in current study showed that 100% and 69.2% of MRSA and MSSA strains, respectively, isolated from BTM samples were multi-drug resistant (MDR). ERIC-PCR profile and spa typing showed that some strains of the same clone had been isolated from different sample sources in different farms. For example, spa type t164 was isolated BTM samples from different farms and human worker nasal swab. This evidence suggested that these strains of the same clone or spa type could be circulated between cattle and humans. Results of this study showed that Palestine BTM samples is a common source of MRSA. Special attention to basic hygiene, good husbandry and biosecurity measures on bovine dairy farms have a tendency to reduce the spread of MRSA in animal population. Careful monitoring of the resistance status of S. aureus in animals, humans and in dairy farm environments is required due to some clones that circulate between them.