Clonality, virulence and antimicrobial resistance of enteroaggregative Escherichia coli from Mirzapur, Bangladesh.

Marie Anne Chattaway,James Rogers,Julia Mtwale,Kaisar Ali Talukder,Michaela Day,Emma White,Alejandro Cravioto,Marwa Ahmad,Claire Jenkins,David Powell,Martin Day,John Wain,Ross Harris

doi:10.1099/jmm.0.000594

Abstract

PurposeThis study investigates the virulence and antimicrobial resistance in association with common clonal complexes (CCs) of enteroaggregative Escherichia coli (EAEC) isolated from Bangladesh. The aim was to determine whether specific CCs were more likely to be associated with putative virulence genes and/or antimicrobial resistance.MethodologyThe presence of 15 virulence genes (by PCR) and susceptibility to 18 antibiotics were determined for 151 EAEC isolated from cases and controls during an intestinal infectious disease study carried out between 2007–2011 in the rural setting of Mirzapur, Bangladesh (Kotloff KL, Blackwelder WC, Nasrin D, Nataro JP, Farag TH et al. Clin Infect Dis 2012;55:S232–S245). These data were then analysed in the context of previously determined serotypes and clonal complexes defined by multi-locus sequence typing.ResultsOverall there was no association between the presence of virulence or antimicrobial resistance genes in isolates of EAEC from cases versus controls. However, when stratified by clonal complex (CC) one CC associated with cases harboured more virulence factors (CC40) and one CC harboured more resistance genes (CC38) than the average. There was no direct link between the virulence gene content and antibiotic resistance. Strains within a single CC had variable virulence and resistance gene content indicating independent and multiple gene acquisitions over time.ConclusionIn Bangladesh, there are multiple clonal complexes of EAEC harbouring a variety of virulence and resistance genes. The emergence of two of the most successful clones appeared to be linked to either increased virulence (CC40) or antimicrobial resistance (CC38), but increased resistance and virulence were not found in the same clonal complexes.

Highlights

Enteroaggregative Escherichia coli (EAEC) have been linked to acute and persistent diarrhoea among children and adults in developing countries [1,2,3,4,5,6] where malnutrition contributes to increasing the severity of symptoms and infection can impair growth and development [7].Strains of EAEC make a significant contribution to the burden of gastrointestinal disease in Bangladesh either as an important independent causal agent [8] or in combination with other pathogens [1, 9, 10]
When stratified by clonal complex (CC) one clonal complexes (CCs) associated with cases harboured more virulence factors (CC40) and one CC harboured more resistance genes (CC38) than the average
In Bangladesh, there are multiple clonal complexes of EAEC harbouring a variety of virulence and resistance genes

Summary

Introduction

Enteroaggregative Escherichia coli (EAEC) have been linked to acute and persistent diarrhoea among children and adults in developing countries [1,2,3,4,5,6] where malnutrition contributes to increasing the severity of symptoms and infection can impair growth and development [7]. Strains of EAEC make a significant contribution to the burden of gastrointestinal disease in Bangladesh either as an important independent causal agent [8] or in combination with other pathogens [1, 9, 10]. In Bangladesh, symptoms of EAEC infection are often severe or persistent and so antibiotic treatment is frequently recommended. The causal link of EAEC in relation to disease in the human population is not absolute [13]. Multiple studies have demonstrated the heterogeneity of EAEC with respect to both plasmid and chromosomal gene content [14, 15] and the 000594 ã 2017 The Authors

Objectives

Methods

Results

Conclusion