Resistance of E. coli strains, recovered from chickens to antibiotics with particular reference to trimethoprim-sulfamethoxazole (septrin).

Thirty-seven strains of E. coli recovered from cases of septicaemia in chicken were tested for sensitivity to 6 antibiotics. Minimum inhibitory concentration (MIC) determinations done on the strains showed resistance to trimethoprim-sulfamethoxazole (septrin) (100%), ampicillin (62.2%), tetracycline (51.4%), kanamycin (13.5%) and gentamicin (2.7%). All were sensitive to chloramphenicol. Conjugation studies showed easy transfer of the resistance factor for septrin to the recipient sensitive strain, K12F-, a 60 megadalton plasmid was transferred in most of the cases (a number of plasmids moved across to K12F- strains). Septrin was chosen as a referral antibiotic because it is used extensively for treating diarrhoeal cases in children in Kenya. The results expressed the possibility of the chicken being the possible source of the septrin resistance gene (plasmid) for humans, and vice versa.