PREVALENCE AND VIRULENCE PROFILING OF MULTIDRUG-RESISTANT SALMONELLAFROM RETAIL VEGETABLES ADJACENT TO POULTRY MARKETS IN SYLHET

Abstract

Salmonella spp., members of the Enterobacteriaceae family, are major cause of diarrheal illnesses global and resides in the gastrointestinal tracts of animals. Multidrug-resistant Salmonella can easily contaminate vegetables sold close to the poultry markets, as poultry animals are the primary reservoir of Salmonella. This study investigated the prevalence of Salmonella spp. in 75 fresh vegetable samples (Cucumber, Tomato, Carrot) collected from different retail locations across Sylhet city. Salmonella was isolated and identified using conventional culture techniques on selective Salmonella-Shigella (SS) agar, Gram staining, and biochemical profiling. The resulting isolates were examined for antibiotic resistance against seven antibiotics widely used in poultry industry (amoxicillin, ciprofloxacin, oxytetracycline, erythromycin, gentamycin, colistin, nalidixic acid) via the disk diffusion assay. A total of 43 isolates (57.33%) obtained from local
markets were confirmed positive for Salmonella with a prevalence of 75.44%, whereas Salmonella was absent in the samples taken from departmental shops. The highest abundance of Salmonella was observed in the Cucumbers (64.285%), followed by Tomatos (62.962%) and Carrots (40%). Antimicrobial resistance profiling revealed that 51.16% of the isolates exhibited multidrug resistance with MAR index ranging from 0.28 to 0.71. All isolates demonstrated susceptibility to gentamycin but resistant to amoxicillin and erythromycin. PCR screening of virulence-associated
genes (invA, fimA, sipB) confirmed their presence and indicated a notable correlation with the multidrug-resistance. The findings demonstrated that the proximity of open poultry stall to a vegetable vending space poses a substantial public health risk, exposing consumers to virulent, antibiotic-resistant foodborne pathogen.