Ibrahim M Alzuheir, Mohammad H Gharaibeh, Myassar O Alekish, Ismail M Malkawi, Farah R Al Oudsi
Human MRSA isolates from both groups showed high AMR, biofilm formation, and virulence potential, indicating substantial zoonotic risk. Occupational exposure to dairy cattle was associated with distinct virulence gene signatures. These findings emphasize the need for continuous molecular surveillance and One Health interventions to mitigate MRSA transmission at the livestock-human interface in Jordan.
BACKGROUND AND AIM: Staphylococcus aureus, particularly methicillin-resistant S. aureus (MRSA), is a major zoonotic pathogen. This study assessed the prevalence of S. aureus and MRSA among individuals in close occupational contact with dairy cattle in Jordan and characterized the recovered MRSA isolates for antimicrobial resistance (AMR), enterotoxin, biofilm, and immune evasion gene profiles.
MATERIALS AND METHODS: A cross-sectional study was conducted using convenience sampling. Nasal swabs were collected from 100 cattle-exposed individuals and 100 non-exposed controls. S. aureus was identified by polymerase chain reaction (PCR) targeting the nuc gene, and MRSA was confirmed by mecA detection. Multiplex PCR assays screened for AMR genes, virulence gene profiles (VGP1-VGP8), biofilm genes, and immune evasion genes. Statistical comparisons between groups were performed using the chi-square test (p < 0.05).
RESULTS: S. aureus was isolated from 82/200 (41.0%) samples, with MRSA comprising 63/82 (76.8%) isolates (32 from exposed and 31 from non-exposed individuals). The blaZ gene was detected in 100% of exposed and 83.9% of non-exposed MRSA isolates. Tetracycline resistance genes (tetK and tetM) were highly prevalent in both groups. Biofilm-associated genes (icaA and icaD) were present in 100% of isolates. Significant differences (p < 0.05) were found for several virulence genes: selr, hlg, and etd were more common in exposed isolates, while selp and sak were more prevalent in non-exposed isolates. The etd gene was detected exclusively in exposed isolates (50%).
CONCLUSION: Human MRSA isolates from both groups showed high AMR, biofilm formation, and virulence potential, indicating substantial zoonotic risk. Occupational exposure to dairy cattle was associated with distinct virulence gene signatures. These findings emphasize the need for continuous molecular surveillance and One Health interventions to mitigate MRSA transmission at the livestock-human interface in Jordan.