Antibiotic Resistance among Commensal Escherichia coli Isolated from Faeces of Cattle in Ado-Ekiti, Nigeria

The goal of this study was to isolate commensal Escherichia coli from faeces of apparently healthy cattle and determine their susceptibility to commonly used antibiotics. Non-repeat faecal samples were collected from 320 ready to be slaughtered cattle and 1,051 commensal isolates of Escherichia coli were recovered from 240 of the faecal samples collected using standard bacteriological methods. All the bacterial isolates were first examined for their susceptibility to antibiotics using protocols as specified by the Clinical Laboratory Standards Institute. The frequency of the antibiotic resistance among the isolates is as follows: ampicillin, 896 (85.3%); cotrimoxazole, 134 (12.8%); gentamicin, 926(88.1%); nalidixic acid, 98 (9.32%); nitrofurantoin, 421 (40.1%); colistin, 662 (63.0%), streptomycin, 710 (67.6%) and tetracycline, 676(64.3%). About 500 isolates were selected based on their antibiotic resistance phenotypes to determine their susceptibility to cephalosporins and flouroquinolones. The susceptibility of the isolates to cephalosporins are ceftazidime, 298 (59.6%), cefoxitin, 463 (92.6%); ceftriaxone, 107 (21.4%) and aztreonam, 241 (48.2%). The susceptibility to the flouroquinolones are: norfloxacin, 39 (7.8%); levofloxacin, 23(4.6%); pefloxacin, 99 (4.6%); ofloxacin, 26 (5.2%) and ciprofloxacin, 55 (11.0%). The study has confirmed that E. coli recovered from cattle show high prevalence of antibiotic resistance.