Susceptibility to antibiotics of Escherichia coli strains isolated from diarrhoeic and non-diarrhoeic livestock in Trinidad

Abstract

The sensitivity of strains of Escherichia coli isolated from calves, piglets, lambs and kids in Trinidad to seven antibiotics was determined. Two hundred and sixty-four (91. 3 %) of 289 strains isolated from diarrhoeic animals and 173 (87. 4 %) of 198 strains from non-diarrhoeic animals exhibited resistance to one or more antibiotics. The difference was not statistically significant (P ≥ 0.05; X²). Regardless of health status, isolates from lambs were least resistant (75.0 %) and those from piglets most resistant (96. 7 %) and the difference was significant (P ≤ 0.001; X²). Strains of E. coli were most resistant to streptomycin (81. 3 %) and tetracycline (78 9 %) and least resistant to chloramphenicol (4.3 %) and gentamycin (4.7 %). The predominant antibiotic resistance pattern for isolates from all sources was streptomycin-tetracycline (27.9 %). It was concluded that the widespread prevalence of resistance to antibiotics reflects their misuse in the local environment.