Transmission of Multi-Drug-Resistant <i>Salmonella</i> from Fresh Vegetables: Implications for Shop-to-Kitchen Contamination

This study investigates the prevalence and antimicrobial resistance profiles of Salmonella spp. in fresh vegetable samples from Karachi, Pakistan. A total of 150 samples, comprising coriander, mint, and spinach, were analyzed using microbiological, biochemical, and molecular techniques. Of these, 93 (62%) samples were positive for Salmonella spp., with the highest prevalence observed in mint (72%), and followed by coriander (60%) and spinach (50%). Microbiological identification involved characteristic colony morphology on XLD and BS agars, while biochemical testing confirmed 80 positive isolates. Molecular confirmation targeting the invA gene identified 76 Salmonella spp., of which 51 were further confirmed as Salmonella Typhi using STY0307-specific PCR. Antibiotic susceptibility testing revealed significant resistance patterns, with S. Typhi isolates demonstrating high sensitivity to meropenem (100%) and azithromycin (97%), while showing the lowest sensitivity to ciprofloxacin (5%). Alarmingly, 25% of isolates were multidrug-resistant (MDR), and 14% were extensively drug-resistant (XDR). The presence of MDR and XDR Salmonella strains in vegetables highlights a critical public health concern, potentially linked to the misuse of antibiotics in agriculture and contamination during production and distribution. These findings underscore the need for improved hygiene practices in vegetable production and stricter regulations on antibiotic use. Additionally, the study emphasizes the importance of surveillance programs to monitor antimicrobial resistance in foodborne pathogens and mitigate the risks associated with consuming contaminated vegetables. Further research is recommended to explore the genetic mechanisms underlying resistance and to develop effective intervention strategies.