Prevalence and Plasmid Profile of Fluoroquinolone-Resistant Escherichia coli isolates from Domestic Animals in Enugu State, Nigeria

Plasmid analysis is an important technique for the determination and characterization of antibiotic resistance traits in procaryotes. This study is aimed at investigating the prevalence and plasmid profile of fluoroquinolone resistant E. coli isolated from domestic livestock in Enugu State, Nigeria. A total of 559 Escherichia coli were isolated from pig, cattle and chicken in Enugu State, Nigeria These isolates were screened for antibiotic susceptibility and plasmid profiles. Thirty four (34) of 559 (6.0%) of the isolates were found to be fluoroquinolone resistant. The prevalence of fluoroquinolone resistance among the E.coli isolates from the animals tested were: pig (5.7, 6.1, 5.7 and 7.8%), cattle (0, 0, 0 and 0%) and chicken (13.6, 14.3, 11.6 and 17.7%) for ciprofloxacin, ofloxacin, levofloxacin and pefloxacin respectively. Plasmid of different sizes were detected in the isolates. Out of the 24 plasmids detected in the FQREC animal isolates, 9 different profiles were recorded; 3 in pigs and 6 in chicken. Isolates with high multi-drug resistance profiles were found to possess multiple plasmids with large sizes in the range of 2026 to 23130 bp. The plasmids were cured to the range of 40 - 80% depending on the source of the isolates thus, confirming the contribution of plasmid in mediating fluoroquinolone resistance in animal FQREC isolates. There was high prevalence of fluoroquinolone-resistant animal E. coli isolates in the studied districts and may constitute a potential reservoir of resistance plasmids that could be transferred to pathogenic bacteria. Keywords. Prevalence, fluoroquinolone, Plasmid profile, Escherichia coli, Domestic animals, Enugu State, Nigeria.