title: Pathogenicity Island O-122 in enteropathogenic Escherichia coli strains is associated with diarrhea severity in children from Lima Peru.
abstract: EPEC is an attaching and effacing diarrheal pathogen that carries a large pathogenicity island, locus for enterocyte effacement (LEE). Recently, the pathogenicity island PAI O-122 was described among non-LEE effectors and found to be associated with diarrhea among atypical EPEC strains. It is unknown if incomplete PAI O-122 could be associated with diarrhea duration and severity. To identify these virulence determinants we analyzed 379 EPEC strains isolated from Peruvian children. EPEC was diagnosed by PCR(eae+, stx-) and classified as typical(t-EPEC) or atypical(a-EPEC). To characterize PAI O-122 we amplified three modules by PCR: Module 1(pagC), Module 2(senA, nleB and nleE) and Module 3(lifA/efa-1). To characterize the large ORF lifA/efa-1 we amplified the regions known as efa-N, efa-M and efa-C. Clinical information was obtained from the cohort study. A total of 379 EPEC strains were able to analyze PAI O-122 genes, 128 (10.4%) EPEC strains were isolated from 1235 diarrhea episodes and 251(9.2%) from 2734 healthy controls. t-EPEC strains were isolated from 14.8% (19/128) of children with diarrhea and 25/251(10.0%) from healthy controls. The most frequent PAI O-122 genes were nleE(37.7%), senA(34.6%) and nleB(37.5%), with similar prevalence among diarrhea and control samples. However, lifA/efa-1 was more common among diarrhea cases than healthy control cases (30.5% vs. 21.1%, p<0.05). The presence of complete PAI O-122 was associated with diarrhea episodes of higher severity among single pathogen infection (33.3% vs. 1.8%, p<0.05) mainly due to the presence of a complete lifA/efa-1 gene. In summary, the gene lifA/efa-1 is significantly associated with diarrheal episodes of higher severity, suggesting to be an important virulent factor.
authors.affiliation: Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru.
authors.forename: Erik H
authors.initials: EH
authors.lastname: Mercado
authors.affiliation: Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru.
authors.forename: Cristian
authors.initials: C
authors.lastname: Piscoche
authors.affiliation: Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru.
authors.forename: Carmen
authors.initials: C
authors.lastname: Contreras
authors.affiliation: Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru.
authors.forename: David
authors.initials: D
authors.lastname: Durand
authors.affiliation: Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru.
authors.forename: Maribel
authors.initials: M
authors.lastname: Riveros
authors.affiliation: ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.
authors.forename: Joaquim
authors.initials: J
authors.lastname: Ruiz
authors.affiliation: Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru; University of Texas School of Public Health, Houston, TX, USA. Electronic address: theresa.j.ochoa@uth.tmc.edu.
authors.forename: Theresa J
authors.initials: TJ
authors.lastname: Ochoa
mesh_terms: D000818:Animals; D002675:Child, Preschool; D004269:DNA, Bacterial / Q000235:genetics; D003967:Diarrhea / Q000382:microbiology* / Q000473:pathology*; D054308:Enteropathogenic Escherichia coli / Q000235:genetics* / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000382:microbiology* / Q000473:pathology*; D005260:Female; D005798:Genes, Bacterial; D044404:Genomic Islands; D006801:Humans; D007223:Infant; D008297:Male; D010568:Peru; D016133:Polymerase Chain Reaction; D012720:Severity of Illness Index
chemical_list: D004269:DNA, Bacterial
keywords: Children; Diarrhea severity; Enteropathogenic escherichia coli; Pathogenicity island O-122; Peru