Abstract

Molecular epidemiology of human and animal ecovariants of Escherichia coli from different regions of Nigeria were studied using their antibiotic susceptibility patterns, plasmid profile and pulsed-field gel electrophoresis (PFGE). E. coli was isolated using eosin methylene blue agar (EMB) and identified by conventional microbiological technique. The isolates were tested against 14 antibiotics using the disc diffusion method. PFGE was performed using XbaI as restriction enzyme according to pulse net protocol. Overall, 42 different antibiotics resistance clusters were observed, with each isolate showing resistance to at least four or more drugs tested. Fingerprinting of 140 isolates by PFGE technique and subsequent cluster analysis revealed a diverse E. coli population belonging to 47 distinct subtypes. Cluster analysis of the 120 KB plasmid bearing isolates indicated that these isolates belonged to one unique clonal group with ≥80% genetic similarity to each other, their animal or human origin, geographical distribution and clinical or non-clinical source notwithstanding. The sharing of drug resistant strains between human and animal population has shown that identical clones are circulating among human and animal population in the study area.

Key words: Escherichia coli, epidemiology, animal ecovariants, cluster analysis.