Detection of virulence genes in Shiga toxigenic <i>Escherichia coli</i> isolated from diarrhoeic and non-diarrhoeic pediatric patients in Ondo State, Nigeria

Abstract

Background:Shiga toxigenic Escherichia coli (STEC) is one of the major causes of intestinal infection, bloody and non-bloody diarrhoea and extra-intestinal complications in humans. It is therefore necessary to enumerate the virulence genes present in isolated STEC strains. Methods: This research investigated the prevalence of STEC and identified some virulence genes (stx1, stx2, and eaeA) from diarrhoeic and non-diarrhoeic pediatric patients of age 1 to 16 years. A total of 243 stool samples were collected from diarrhoeic and non-diarrhoeic pediatric patients (in ratio 43:200) in four different State Specialist Hospitals in Ondo State, Nigeria. Polymerase chain reaction (PCR) assay was used for detection of Shiga toxin-producing E. coli. The virulence genes (stx1, stx2, and eaeA) were detected by PCR assay. Results: Out of the 243 samples, 163 (67%) were positive for E. coli and specifically 6 of them were positive for E. coli O157 (3.7%). Exactly 50% of the 6 E. coli O157 contained eaeA while all the strains contained Stx1 and Stx2. The results obtained also revealed that 6 strains that were non-O157:H7 STEC also contained Stx1 and four strains contained Stx2 genes. Conclusion: The results obtained from this study revealed that Stx1 and Stx2 genes are of the genes responsible for the virulence of STEC among diarrhoeic and non-diarrhoeic pediatric patients.