Molecular Detection of Virulence Genes and Antibiotic Resistance Patterns of <i>Escherichia coli</i> O157:H7 Isolated from Raw Beef Sold in Abeokuta, South-West Nigeria

Abstract

Escherichia coli O157:H7 is an important food-borne pathogen that can cause diarrhea, haemorrhagic colitis and haemolytic uremic syndrome. This study was conducted to investigate the prevalence, virulence genes and antibiotic resistance patterns of E. coli O157:H7 in raw beef meat sold in Abeokuta, South west Nigeria. One hundred and twenty samples of raw beef meat were collected from four abattoirs and examined for the presence of E. coli O157:H7. The virulence genes (stx1, stx2, eaeA and hlyA) were detected in E. coli O157:H7 isolates by polymerase chain reactions. The antibiotic resistance patterns of the isolates were determined using Kirby-Bauer disc diffusion method. Of 120 samples analyzed, 8 (6.67%) were contaminated with E. coli O157:H7, with highest prevalence rate (2.5%) found in beef samples collected from Rounder abattoir. The virulence genes (stx 1 and stx 2 genes) were detected in 7 (87.5%) of E. coli O157:H7 isolates while no eaeA and hlyA genes were found. All the E. coli O157:H7 isolates were highly resistant to tetracycline, ampicillin, erythromycin and chloramphenicol and sensitive to ciprofloxacin and streptomycin. The results of this study revealed that raw beef meat could be potential vehicles of transmitting multi-drug resistant, shiga toxin-producing E. coli O157:H7 to humans.

Keywords: Pathogen, E. coli O157:H7, virulence genes, antibiotic-resistance, beef meat