Antibiogram, antibiotic resistance genes and health risks of Listeria species from fruits and vegetables in selected locations in Nigeria

<ns3:p> Abstract* Background Fresh produce is a vital vehicle for the transmission of foodborne pathogens, yet data from low- and middle-income countries on contamination levels and associated health risks remain scarce. Methods This study provided an analysis of <ns3:italic>Listeria</ns3:italic> species contamination in 208 fruit and vegetable samples from major geopolitical regions in Nigeria. Conventional microbiological techniques and molecular methods were used for the analysis. Results We reported a high prevalence (38.5%) and substantial bacterial loads (up to 8.33×10 <ns3:sup>2</ns3:sup> CFU/25g) among the organically grown crops, with produce from Northern states exhibiting the highest contamination. Genetic characterisation revealed significant diversity, including novel strains and others closely related to global clones, confirming a resilient environmental presence. Importantly, antibiotic susceptibility testing uncovered alarming resistance rates to vancomycin (83.1%) and oxacillin (88.1%), with hierarchical clustering identifying distinct multidrug-resistant clusters. The presence of resistance genes ( <ns3:italic>vanA, vanB, tetL, tetM</ns3:italic> ) and the virulence gene <ns3:italic>hly</ns3:italic> was confirmed. A quantitative microbial risk assessment (QMRA), incorporating this empirical data, estimated the annual probability of illness, highlighting high-risk produce-region combinations. Conclusions These findings demonstrate that fresh produce in Nigeria is a significant reservoir of pathogenic, antimicrobial-resistant <ns3:italic>L. monocytogenes</ns3:italic> , posing a serious public health threat. This study highlights the urgent need for targeted interventions, including enhanced agricultural water safety and strengthened surveillance of antimicrobial resistance, to mitigate risks and support evidence-based food safety policies in Nigeria and similar regions. </ns3:p>