TRANSFERABLE ANTIBIOTIC-RESISTANCE IN ESCHERICHIA-COLI ISOLATED FROM HEALTHY NIGERIAN SCHOOL-CHILDREN

Three hundred and ninety-six E. coli isolates obtained from apparently healthy school children in Ile-Ife, Nigeria, were tested for their su sceptibility to 11 different antibiotics. Of these, only gentamicin, c efotaxime and nalidixic acid were found to have significant in vitro a ctivity against most of the isolates. The incidence of antibiotic resi stances encountered varied between 24% for trimethoprim and 55.5% for the sulphonamide. It was further observed that 47.5% of the isolates w ere identified as being multiply resistant, since they were simultaneo usly resistant to at least three different antibiotics. The 86 trimeth oprim-resistant isolates tested were found to be able to transfer this resistance trait together with resistance genes of to other antibioti cs, into a plamidless strain of E. coli by conjugation. Seventy-seven of the trimethoprim-resistant isolates were also found to be classifia ble into the types of dihydrofolate reductases responsible for the obs erved resistance on the basis of hybridization experiments. The result s of this study indicate that there is a large reservoir of antibiotic resistances within the community, and that the resistance genes were easily transferable to other strains even without direct exposure to a ntibiotics.