title: Prospective cohort study of enterotoxigenic Escherichia coli infections in Argentinean children.
abstract: In a follow-up study, enterotoxigenic Escherichia coli (ETEC) infections in 145 children from two communities located in northeastern Argentina were monitored for 2 years. The occurrence of diarrhea was monitored by weekly household visits. Of 730 fecal specimens collected, 137 (19%) corresponded to diarrheal episodes. ETEC was isolated from a significantly higher proportion of symptomatic (18.3%) than asymptomatic (13.3%) children (P = 0.04541). Individuals of up to 24 months of age were found to have a higher risk of developing ETEC diarrhea than older children (odds ratio [OR], 3.872; P = 0.00021). When the toxin profiles were considered, only heat stable enterotoxin (ST)-producing ETEC was directly associated with diarrhea (P = 0.00035). Fifty-five percent of the ETEC isolated from symptomatic children and 19% of the ETEC isolated from asymptomatic children expressed one of the colonization factors (CFs) investigated, i.e., CF antigen I (CFA/I), CFA/II, CFA/III, and CFA/IV; coli surface antigens CS7 and CS17; and putative CFs PCFO159, PCFO166, and PCFO20, indicating a clear association between diarrhea and ETEC strains that carry these factors (P = 0.0000034). The most frequently identified CFs were CFA/IV (16%), CFA/I (10%), and CS17 (9%). CFs were mostly associated with ETEC strains that produce ST and both heat-labile enterotoxin and ST. Logistic regression analysis, applied to remove confounding effects, revealed that the expression of CFs was associated with illness independently of the toxin type (OR, 4.81; P = 0.0003). When each CF was considered separately, CS17 was the only factor independently associated with illness (OR, 16.6; P = 0.0151). Most CFs (the exception was CFA/IV) fell within a limited array of serotypes, while the CF-negative isolates belonged to many different O:H types. These results demonstrate that some CFs are risk factors for the development of ETEC diarrhea.
authors.affiliation: Departamento de Bacteriologia, Instituto Nacional de Enfermedades Infecciosas, "ANLIS Dr. Carlos G. Malbrán", Ministerio de Salud y Acción Social, (1281) Capital Federal, Argentina.
authors.forename: G I
authors.initials: GI
authors.lastname: Viboud
authors.forename: M J
authors.initials: MJ
authors.lastname: Jouve
authors.forename: N
authors.initials: N
authors.lastname: Binsztein
authors.forename: M
authors.initials: M
authors.lastname: Vergara
authors.forename: M
authors.initials: M
authors.lastname: Rivas
authors.forename: M
authors.initials: M
authors.lastname: Quiroga
authors.forename: A M
authors.initials: AM
authors.lastname: Svennerholm
mesh_terms: D001426:Bacterial Proteins / Q000032:analysis; D002675:Child, Preschool; D015331:Cohort Studies; D003967:Diarrhea / Q000209:etiology; D004768:Enterotoxins / Q000032:analysis; D004926:Escherichia coli / Q000145:classification / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000382:microbiology*; D005260:Female; D036781:Fimbriae Proteins; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007422:Intestines / Q000382:microbiology; D008297:Male; D011446:Prospective Studies; D012703:Serotyping
chemical_list: D001426:Bacterial Proteins; D004768:Enterotoxins; C022924:colonization factor antigens; D036781:Fimbriae Proteins