Isolation, Molecular Detection and Antimicrobial Susceptibility Profile of Escherichia coli O157:H7 in Household - reared Small Ruminants in Zaria Metropolis, Kaduna State, Nigeria

Abstract

Escherichia coli O157:H7 is a zoonotic enteric pathogen of public health significance worldwide. A cross-sectional study was carried out during which 384 faecal samples of household-reared small ruminants and water used in the various houses where the animals are reared were collected. The samples were enriched on tryptone soya broth and cultured on EMB and CT-SMAC to isolate E. coli and E. coli O157:H7 respectively; subjected to conventional biochemical tests and E. coli O157:H7 was confirmed using Wellcolex latex agglutination test kit. E. coli O157:H7 isolates were subjected to antimicrobial susceptibility test and multiplex PCR was carried out to detect the presence of virulence genes stx1, stx2, eaeA and hlyA. The results of the isolation showed isolation rate of E. coli O157:H7 of 4.69% (9/192), 0.52% (1/192) which were obtained from faeces and water samples respectively. The results of the characterisation showed that one of the E. coli O157:H7 isolated harboured the eaeA and hlyA genes but was negative for stx1 and stx2 genes. The highest number of isolates showed resistance to erythromycin (90.9%) while the least was to gentamicin (6.3%). About 97.7% (43/44) of the isolates had multiple antibiotic resistance index greater than 0.2. In conclusion, household-reared small ruminants in the study area were found to be reservoirs of E. coli O157:H7 and humans living within these households are at risk of infection. The multiple antibiotic resistance recorded in this study suggests wide spread use of antimicrobial drugs in the study area.

Keywords: Escherichia coli O157:H7, Household-reared small ruminants, Latex agglutination, Multiplex PCR, Antimicrobial sensitivity