African Journal of Biotechnology Vol. 6 (18), pp. 2135-2139, 19 September 2007   

ISSN 1684–5315 © 2007 Academic Journals        

Full Length Research Paper

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

David, O. M.* and Odeyemi, A. T.

Department of Microbiology, University of Ado-Ekiti, P.M.B. 5363, Ado-Ekiti, Nigeria.

*Corresponding author. E-mail:davidgenerationng@yahoo.com.

Accepted 26 January, 2007

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%), augumentin/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 Concen-trations (MICs) of the antibiotics to the isolates range between 4.0 and >16.0 µg/ml. cotrimoxazole and gentamicin recorded the highest MIC compared with other antibiotics.

Key words: Listeria monocytogenes, vegetable, cow dung, antibiotic resistance, environmental isolates.