Escherichia coliand Community-acquired Gastroenteritis, Melbourne, Australia

Roy M Robins-Browne,Nicole A Lister,Frances Oppedisano,Christopher K Fairley,Jacinta Russell,Marija Tauschek,Karl A Bettelheim,Margaret E Hellard,Anne-Marie Bordun,Vicki R Bennett-Wood,Martha I Sinclair

doi:10.3201/eid1010.031086

Abstract

As part of a study to determine the effects of water filtration on the incidence of community-acquired gastroenteritis in Melbourne, Australia, we examined fecal samples from patients with gastroenteritis and asymptomatic persons for diarrheagenic strains of Escherichia coli. Atypical strains of enteropathogenic E. coli (EPEC) were the most frequently identified pathogens of all bacterial, viral, and parasitic agents in patients with gastroenteritis. Moreover, atypical EPEC were more common in patients with gastroenteritis (89 [12.8%] of 696) than in asymptomatic persons (11 [2.3%] of 489, p < 0.0001). Twenty-two random isolates of atypical EPEC that were characterized further showed marked heterogeneity in terms of serotype, genetic subtype, and carriage of virulence-associated determinants. Apart from the surface protein, intimin, no virulence determinant or phenotype was uniformly present in atypical EPEC strains. This study shows that atypical EPEC are an important cause of gastroenteritis in Melbourne.

Highlights

As part of a study to determine the effects of water filtration on the incidence of community-acquired gastroenteritis in Melbourne, Australia, we examined fecal samples from patients with gastroenteritis and asymptomatic persons for diarrheagenic strains of Escherichia coli
Analysis of the data pertaining to patients in whom enteroaggregative E. coli (EAEC) and atypical enteropathogenic E. coli (EPEC) were identified showed that atypical EPEC were more frequent in younger persons; patients with atypical EPEC were a median age of 3.4 years, compared with 7.4 years for the symptomatic group overall (p < 0.0001; Mann-Whitney test, 2-tailed)
The proven virulence determinants of EPEC include genes within the locus for enterocyte effacement (LEE), notably intimin, and bundle-forming pili (Bfp), which is encoded by EPEC adherence factor plasmid (EAF) [5]

Summary

Introduction

As part of a study to determine the effects of water filtration on the incidence of community-acquired gastroenteritis in Melbourne, Australia, we examined fecal samples from patients with gastroenteritis and asymptomatic persons for diarrheagenic strains of Escherichia coli. Strains of Escherichia coli that cause diarrhea are classified into pathotypes (or virotypes) according to their specific virulence determinants [1]. These virulence determinants give each pathotype the capacity to cause a clinical syndrome with distinctive epidemiologic and pathologic characteristics. We conducted a study to determine if the water supply of Melbourne, Australia’s second largest city with >3 million inhabitants, is a source of intestinal pathogens that are responsible for community-acquired gastroenteritis. Among the pathogens that were sought were diarrheagenic E. coli, including atypical EPEC, which emerged as the predominant cause of gastroenteritis in this community

Methods

Results

Conclusion