Frequency of Detection ofEscherichia coli,Salmonellaspp., andCampylobacterspp. in the Faeces of Wild Rats (Rattusspp.) in Trinidad and Tobago

Abstract

The study was conducted to determine the frequency of isolation ofSalmonella,CampylobacterandE. coliO157 in the faecal samples of rats trapped across the regional corporations in Trinidad and to assess their resistance to antimicrobial agents. A total of 204 rats were trapped for the detection of selected bacteria. Standard methods were used to isolateSalmonella,CampylobacterandE. coliO157. Characterization ofE. coliwas done on sorbitol MacConkey agar to determine non-sorbitol fermentation, blood agar to determine haemolytic and mucoid colonies and by usingE. coliO157 antiserum to determine O157 strain. The disc diffusion method was used to determine resistance to nine antimicrobial agents. Of the 204 rats, 4 (2.0%), 7 (3.4%) and 171 (83.8%) were positive forSalmonellaspp.,Campylobacterspp. andE. coli, respectively. Of the 171 isolates ofE. colitested 0 (0.0%), 25 (14.6%) and 19 (11.1%) were haemolytic, mucoid and non-sorbitol fermenters, respectively. All isolates were negative for the O157 strain. The frequency of resistance to the 9 antimicrobial agents tested was 75% (3 of 4) forSalmonella, 85.7% (6 of 7) ofCampylobacterspp. and 36.3% (62 of 171) forE. coli(;χ2).