Antibiotic resistant pattern of environmental isolates of Listeria monocytogenes from Ado-Ekiti, Nigeria

Incidence of Listeria monocytogenes in cow manure, agricultural soil, and common vegetables sold in major markets in Ado-Ekiti, Nigeria was determined. Antibiotic resistant pattern of the isolates was examined by paper disk assay. A total of 196 environmental samples were cultured on a selective medium out of which 153 (78.1%) were positive for L. monocytogenes. Erythromycin was the most effective antibiotic against the isolates with the least resistance (28.1%) while chloramphenicol proved to be least effective with resistant of 52.29%. The multiple-antibiotic resistant pattern of the isolates showed augumentin/amoxicillin (33.3%),  lugumentin/erythromycin (24.18%), and cotrimoxazole/ chloramphenicol/amoxicillin (28.8%) to be most prominent. The least value was observed in cloxacilin/cotrimoxazole/gentamycin with 15.34%. The modal values of the Minimum Inhibitory Concentrations (MICs) of the antibiotics to the isolates range between 4.0 and >16.0 ig/ml. cotrimoxazole and gentamicin recorded the highest MIC compared with other antibiotics.