Antibiotic Resistance Profile and Carriage of the Panton-Valentine Leukocidin (pvl) Gene in Coagulase-Negative Staphylococci Isolated from Sold Edible Telfairia occidentalis Vegetables

Abstract

Background: Coagulase-negative Staphylococci (CoNS) have emerged as significant opportunistic pathogens, particularly in foodborne infections. The presence of virulence genes such as Panton-Valentine leukocidin (pvl) in CoNS isolated from fresh vegetables represents an underrecognized public health threat. This study investigated the antibiotic resistance profile and prevalence of the pvl gene in CoNS isolated from Telfairia occidentalis vegetables sold in Enugu, Nigeria. Methods: Twenty-five Telfairia occidentalis vegetable samples were collected from the Old Artisan Market in Enugu. CoNS were isolated using standard microbiological techniques and confirmed via biochemical testing. Antibiotic susceptibility testing was performed against 15 antibiotics using the disk diffusion method according to CLSI guidelines. PCR screening was conducted to detect the pvl gene in selected isolates. Results: Twelve CoNS isolates (48.0%) were recovered from T. occidentalis samples. Isolates exhibited high resistance to β-lactams (amoxicillin-clavulanic acid 83.3%, cefoxitin 100%, oxacillin 100%), carbapenems (imipenem 100%), sulfonamides (trimethoprim-sulfamethoxazole 100%), and protein synthesis inhibitors (chloramphenicol 91.7%). Susceptibility was observed to fluoroquinolones (ciprofloxacin 83.3%, levofloxacin 91.7%) and meropenem (75.0%). Notably, 25.0% (3/12) of isolates harbored the pvl gene. pvl-positive isolates demonstrated significantly higher resistance to multiple antibiotics compared to pvl-negative isolates, including vancomycin (100% vs. 44.4%) and gentamicin (100% vs. 44.4%). Conclusion: This study reveals the presence of pvl-harboring, multidrug-resistant CoNS on fresh vegetables in Enugu, highlighting a potential route for community transmission of virulent strains. The correlation between pvl carriage and enhanced antibiotic resistance suggests these isolates may pose a dual threat of increased pathogenicity and treatment failure. Enhanced food safety surveillance and antimicrobial stewardship are urgently needed.