Surveillance of Diarrheagenic Escherichia coli Strains Isolated from Diarrhea Cases from Children, Adults and Elderly at Northwest of Mexico.

Adrian Canizalez-Roman,Jorge E Vidal,Gerardo Alapizco-Castro,Edgar Gonzalez-Nuñez,Héctor M Flores-Villaseñor,Nidia León-Sicairos,Jorge Velazquez-Roman,Secundino Muro-Amador,J Alberto Díaz-Quiñonez

doi:10.3389/fmicb.2016.01924

Abstract

Diarrheagenic Escherichia coli (DEC) strains are a main cause of gastrointestinal disease in developing countries. In this study we report the epidemiologic surveillance in a 4-year period (January 2011 to December 2014) of DEC strains causing acute diarrhea throughout the Sinaloa State, Mexico. DEC strains were isolated from outpatients of all ages with acute diarrhea (N = 1,037). Specific DEC pathotypes were identified by PCR-amplification of genes encoding virulence factors. The adhesion phenotype and antibiotic resistance were also investigated. DEC strains were detected in 23.3% (242/1037) of cases. The most frequently DEC strain isolated was EAEC [(12.2%), 126/242] followed by EPEC [(5.1%), 53/242], ETEC [(4.3%), 43/242] DAEC [(1.4%), 15/242], STEC [(0.3%), 3/242], and EIEC [(0.2%), 2/242]. EHEC strains were not detected. Overall DEC strains were more prevalent in children ≤2 years of age with EPEC strains the most common of DEC pathotypes. While ∼65% of EAEC strains were classified as typical variant based on the aggregative adherence to in vitro cultures of HEp-2 cells, a high proportion of EPEC strains was classified as atypical strains. EAEC, EPEC, ETEC, and DAEC strains were distributed in the north, central and south regions of Sinaloa state. Among all DEC strains, >90% were resistant to at least one commonly prescribed antibiotic. Strains were commonly resistant to first-line antibiotics such as tetracycline, ampicillin, and sulfamethoxazole-trimethoprim. Furthermore, more than 80% of DEC isolates were multi-drug resistant and EPEC and DAEC were the categories with major proportion of this feature. In conclusion, in nearly one out of four cases of acute diarrhea in Northwestern Mexico a multi-drug resistant DEC strain was isolated, in these cases EAEC was the most prevalent (52%) pathotype.

Highlights

Diarrhea remains an important cause of morbidity and mortality globally, among infants and young children
The most prevalent Diarrheagenic Escherichia coli (DEC) pathotype isolated was Enteroaggregative E. coli (EAEC) accounting for 52% (n = 126) of all cases followed by Enteropathogenic E. coli (EPEC) [21.9% (n = 53)], Enterotoxigenic E. coli (ETEC) [17.8% (n = 43)], Diffusely adherent E. coli (DAEC) [6.2% (n = 15)], STEC [1.23% (n = 3)], and Enteroinvasive E. coli (EIEC) [0.82% (n = 2)]
The age group from where more DEC strains were isolated from diarrhea cases was those children ≤2 years of age with 30.4% (N = 82) and of these almost half cases were produced by EAEC strains

Summary

Introduction

Diarrhea remains an important cause of morbidity and mortality globally, among infants and young children. The different pathotypes of diarrheagenic Escherichia coli (DEC) are a main cause of diarrhea in developing countries (Nataro and Kaper, 1998). A STEC strain serotype O104:H4 was responsible in 2011 for the largest epidemic outbreaks in Germany. This multidrug-resistant STEC caused over 3800 cases of diarrhea without hemolytic uremic syndrome (HUS) and over 830 cases with HUS, leading to 54 deaths. DEC pathotypes are a main source of diarrhea and of public health relevance, strains are not routinely sought as enteric pathogens in clinical laboratories worldwide. Prevalence of diarrhea caused by DEC strains are generally unknown, in areas where DEC strains are believed endemic

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Conclusion