Affiliation:
1. Department of Pediatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
2. Bacteriological Laboratory, Mother and Child Health Center, Ulaanbaatar, Mongolia
3. Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland 21201
Abstract
ABSTRACT
Diarrhea remains one of the main sources of morbidity and mortality in the world, and a large proportion is caused by diarrheagenic
Escherichia coli
. In Mongolia, the epidemiology of diarrheagenic
E. coli
has not been well studied. A total of 238
E. coli
strains from children with sporadic diarrhea and 278
E. coli
strains from healthy children were examined by PCR for 10 virulence genes: enteropathogenic
E. coli
(EPEC)
eae
,
tir
, and
bfpA
; enterotoxigenic
E. coli
(ETEC)
lt
and
st
; enteroinvasive
E. coli
(EIEC)
ipaH
; enterohemorragic
E. coli stx1
and
stx2
; and enteroaggregative
E. coli
(EAEC)
aggR
and
astA
. EAEC strains without AggR were identified by the HEp-2 cell adherence test. The detection of EAEC, ETEC, EPEC, and EIEC was significantly associated with diarrhea. The incidence of EAEC (15.1%), defined by either a molecular or a phenotypic assay, was higher in the diarrheal group than any other category (0 to 6.0%). The incidence of AggR-positive EAEC in the diarrheal group was significantly higher than in the control group (8.0 versus 1.4%;
P
= 0.0004), while that of AggR-negative EAEC was not (7.1 versus 4.3%). Nineteen AggR-positive EAEC strains harbored other EAEC virulence genes—
aggA
, 2 (5.5%);
aafA
, 4 (11.1%);
agg-3a
, 5 (13.8%);
aap
, 8 (22.2%);
aatA
, 11 (30.5%);
capU
, 9 (25.0%);
pet
, 6 (16.6%); and
set
, 3 (8.3%)—and showed 15 genotypes. EAEC may be an important pathogen of sporadic diarrhea in Mongolian children. Genetic analysis showed the heterogeneity of EAEC but illustrated the importance of the AggR regulon (denoting typical EAEC) as a marker for virulent EAEC strains.
Publisher
American Society for Microbiology
Cited by
118 articles.
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