title: Characterization of enterotoxigenic Escherichia coli strains isolated from Nicaraguan children in hospital, primary care and community settings.
abstract: Enterotoxigenic Escherichia coli (ETEC) is one of the most common causes of diarrhoea among young children in developing countries. ETEC vaccines offer promise in reducing the burden of ETEC disease, but the development of these vaccines relies on the characterization of ETEC isolates from a variety of settings. To best reflect the full spectrum of ETEC disease in León, Nicaragua, the aim of this study was to characterize ETEC strains isolated from children with diarrhoea attending different settings (hospital, primary care clinics and in the community) and children from different age groups. We characterized ETEC isolates in terms of their colonization factors (CFs) and enterotoxins, and determined whether these factors varied with setting and age group. Diarrhoeal stool samples were obtained from children under the age of 60 months from: (1) the regional public hospital, (2) four public primary care clinics, and (3) a population-based cohort. In total, 58 ETEC-positive isolates were analysed by multiplex-PCR assays for the identification of CFs (CS1, CS2, CS3, CS4, CS5, CS6, CS7, CS8, CS12, CS13, CS14, CS15, CS17, CS18, CS19, CS20, CS21, CS22 and CFA/I), and enterotoxins [heat-labile toxin (LT) and heat-stable variants STh and STp]. The frequency of CFs and enterotoxins was compared among the three settings and for different age groups, using Fisher's exact test or a χ(2) test. At least one CF was detected among one-half of samples; CS19 was detected among all strains in which a CF was identified, either alone or in combination with another CF. Among all CFs detected, 91.7 % were identified as members of the class 5 fimbrial family. CFs were detected more commonly among samples from infants captured in the health facility setting compared with the community setting. Overall, LT was detected among 67.2 % of samples, STh was detected among 20.7 % and both enterotoxins were detected among 12.1 %. The enterotoxin STh was detected more commonly among cases in the community, whilst a combination of STh and LT was detected more commonly among cases treated in health facilities. Our results suggest that, to protect against diarrhoeal cases associated with this E. coli pathotype in León, Nicaragua, an ETEC vaccine that effectively targets the archeotype CFA/I of the class 5 fimbrial family would be the most effective in this setting.
authors.affiliation: Department of Microbiology, Faculty of Medical Sciences, National Autonomous University of Nicaragua (UNAN), León, Nicaragua.
authors.forename: Samuel
authors.initials: S
authors.lastname: Vilchez
authors.affiliation: Department of Family Medicine, University of North Carolina at Chapel Hill, 590 Manning Drive, Chapel Hill, NC, USA.
authors.forename: Sylvia
authors.initials: S
authors.lastname: Becker-Dreps
authors.affiliation: Department of Microbiology, Faculty of Medical Sciences, National Autonomous University of Nicaragua (UNAN), León, Nicaragua.
authors.forename: Erick
authors.initials: E
authors.lastname: Amaya
authors.affiliation: Department of Microbiology, Faculty of Medical Sciences, National Autonomous University of Nicaragua (UNAN), León, Nicaragua.
authors.forename: Claudia
authors.initials: C
authors.lastname: Perez
authors.affiliation: Department of Microbiology, Faculty of Medical Sciences, National Autonomous University of Nicaragua (UNAN), León, Nicaragua.
authors.forename: Margarita
authors.initials: M
authors.lastname: Paniagua
authors.affiliation: Department of Microbiology, Faculty of Medical Sciences, National Autonomous University of Nicaragua (UNAN), León, Nicaragua.
authors.forename: Daniel
authors.initials: D
authors.lastname: Reyes
authors.affiliation: Department of Microbiology, Faculty of Medical Sciences, National Autonomous University of Nicaragua (UNAN), León, Nicaragua.
authors.forename: Felix
authors.initials: F
authors.lastname: Espinoza
authors.affiliation: Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, S-141 86, Stockholm, Sweden.
authors.forename: Andrej
authors.initials: A
authors.lastname: Weintraub
mesh_terms: D001427:Bacterial Toxins / Q000235:genetics; D002675:Child, Preschool; D017714:Community-Acquired Infections / Q000382:microbiology; D003428:Cross Infection / Q000382:microbiology; D003967:Diarrhea / Q000382:microbiology*; D054307:Enterotoxigenic Escherichia coli / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D004768:Enterotoxins / Q000235:genetics; D004927:Escherichia coli Infections / Q000382:microbiology*; D029968:Escherichia coli Proteins / Q000235:genetics; D022361:Escherichia coli Vaccines / Q000276:immunology / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology; D005260:Female; D036781:Fimbriae Proteins / Q000235:genetics; D014644:Genetic Variation; D006761:Hospitals; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D060885:Multiplex Polymerase Chain Reaction; D009527:Nicaragua; D011320:Primary Health Care
chemical_list: D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D022361:Escherichia coli Vaccines; C022924:colonization factor antigens; C034151:heat stable toxin (E coli); D036781:Fimbriae Proteins; C027538:heat-labile enterotoxin, E coli