Pathogenicity Island O-122 in enteropathogenic Escherichia coli strains is associated with diarrhea severity in children from Lima Peru

Erik H. Mercado, Cristian Piscoche, Carmen Contreras, David Durand, Maribel Riveros, Joaquim Ruiz, Theresa J. Ochoa

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


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.

Original languageEnglish
Pages (from-to)231-236
Number of pages6
JournalInternational Journal of Medical Microbiology
Issue number4
StatePublished - 1 Jun 2016


  • Children
  • Diarrhea severity
  • Enteropathogenic escherichia coli
  • Pathogenicity island O-122
  • Peru


Dive into the research topics of 'Pathogenicity Island O-122 in enteropathogenic Escherichia coli strains is associated with diarrhea severity in children from Lima Peru'. Together they form a unique fingerprint.

Cite this