Prevalence and antibiotic resistance profile of Salmonella spp. strains isolated from the vegetable food chain in Niamey, Niger

Background Salmonellosis is the main cause of collective food poisoning in humans. They are bacterial infections caused by various Salmonella species. The overall aim of this study was to determine the prevalence and antibiotic resistance phenotype of Salmonella strains isolated from vegetables in the urban community of Niamey. Methods To this end, one hundred and twenty-four (124) samples of some vegetables (carrot, lettuce, onion and tomato) were taken from market garden sites and markets in Niamey. Salmonella were tested using the ISO 6579:2017 4-step method: pre-enrichment, enrichment, isolation and biochemical identification, and the antibiotic resistance phenotype was determined using the standard Kirby-Bauer agar diffusion method. Results Some sampling sites showed high Salmonella prevalences, notably site 1 (75.00%) and market 4 (40.00%). The overall level of Salmonella contamination in vegetables was 13.71%, including carrot (25.00%) and lettuce (15.38%) samples. The most common resistance phenotypes were Ceftriazone (100%), Amoxicillin + Clavulanic Acid (76.92%), Ciprofloxacin (46.15%), Aztreonam (33.33%) and Imipenem (30.77%). Conclusion The presence of multidrug-resistant Salmonella strains in vegetables reflects the potential risk associated with their consumption. It is important to research the potential resistance and virulence genes of these strains for better management of infectious diseases.