Drug resistance in Escherichia coli strains isolated from animals

Abstract

It were screened for drug resistance 375 E. coli strains, isolated from animals. In relation to the origin, they were obtained from fowls, calves, horses, lambs and swine,
corresponding a total of 75 strains to each of these related groups. The bacterial lineage selection was dependant on a preliminary determination of its resistance levels to the sulphadyazine, to streprômycin, to chloramphenicol, to cephalotin, to hetacylin, to tetracycline, and to the kanamycin.
The conçentration of each of these drugs variyed from 1 to 1 000 mcg/ml, and it were considered as resistants, those strains that grew in 20 mcg/ml. In these condictions, it were observed that 333 strains were resistants to sulphadyazine, 284 to tetracycline, 300 to chloramphenicol, 74 to  treptomycin, 19 to cephalotyn, seven to hetacylin and two to the kanamycin. From all of these 375 above mentioned E. coli strains, were detected 20 resistance models, with the predominance of those integrated by three or four determinants for drug resistance, The S-C1- T resistance model showed higher incidence with a total of 132 strains coming in second place, 45 strains, characterized by the S-C1- T-E resistance determinants.