[Association of patterns of Escherichia coli adherence to HEp-2 cells with acute and persistent diarrhea].
In Brazil diarrhea is the cause of approximately 15% of death among infants. Enteropathogenic E coli is the most important bacterial agent causing acute diarrhea, which is defined as less than 14 days of duration. About 30% of these cases may evolve to persistent diarrhea, defined as lasting more than 14 days. In this work it was carried out a case-control study including 34 children under 2 years of age, and admitted to hospital facilities in São Paulo for rehydration therapy. Thirty-four age matched children hospitalized in the same facilities, and presenting no gastrointestinal symptoms were included as controls. Stool samples were analyzed for the presence of bacterial pathogens (diarrheagenic E coli, Shigella, Salmonella, Yersinia, and Campylobacter), protoparasytes, rotavirus, and enteric adenovirus. The E coli strains isolated were analyzed for their ability to adhere to HEp-2 cultured cells, in a 3 h adhesion assay. Search for homology with DNA probes for localized adherence (EAF, eaeA probes), AA (enteroagregative adherence) (AA probe), and diffuse adherence (F1845, AIDA-I probes) was carried out by the colony hybridization method. Twenty-four of the cases were acute diarrhea and 10 persistent diarrhea. Strains with localized adherence were associated with acute and persistent diarrhea. About 23.5% of E coli were associated with typical Enteropathogenic E coli strains (EAF+, eaeA+). Enteroaggregative E coli (EAggEC) (AA+) was isolated only from cases and in similar frequency for acute and persistent diarrhea. Diffusely adherent E coli (DAEC) which did not hybridize with the diffuse adherence probes were isolated among cases and controls. E coli eaeA+ with localized-like adherence was isolated from cases in a frequency three times higher than in controls, suggesting that it may really have a pathogenic potential.
Scaletsky
I C
IC
Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, Escola Paulista de Medicina, Brasil. scaletsky.dmip@epm.br
Pedroso
M Z
MZ
Morais
M B
MB
Carvalho
R L
RL
Silva
R M
RM
Fabbricotti
S H
SH
Fagundes-Neto
U
U
D000208:Acute Disease; D001422:Bacterial Adhesion / Q000502:physiology*; D003967:Diarrhea / Q000382:microbiology*; D004926:Escherichia coli / Q000472:pathogenicity / Q000502:physiology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn