BACKGROUND: Enteroaggregative Escherichia coli (EAEC) are a heterogeneous category of emerging pathogens associated with acute and persistent diarrhea. METHODS: We performed a case-control study to evaluate the association of EAEC strains and their virulence markers with infantile diarrhea in Brasilia, Brazil. RESULTS: Of the EAEC markers that were tested, only EAEC heat-stable toxin (EAST1), protein involved in colonization (Pic), and the CVD432 sequence showed positive correlation with diarrhea; however, these virulence traits presented associations with distinct clinical characteristics. Although CVD432-positive strains were associated with persistent diarrhea, EAST1-positive strains were statistically correlated with acute diarrhea only in children >6 months of age. Typical EAEC strains were found with equal frequency in case patients and control subjects. O antigens of enteropathogenic E. coli (EPEC) were also sought, and the data showed that the EAEC markers are frequently segregated into 3 EPEC serogroups: O126, O128, and O158. CONCLUSIONS: The presence of EPEC O antigens along with EAEC markers influenced the positive association of E. coli strains with diarrhea. Concerning the detection of the AA phenotype, the CVD432 sequence presented a low positive predictive value, regardless of its high specificity as a marker.
BACKGROUND: Enteroaggregative Escherichia coli (EAEC) are a heterogeneous category of emerging pathogens associated with acute and persistent diarrhea. METHODS: We performed a case-control study to evaluate the association of EAEC strains and their virulence markers with infantile diarrhea in Brasilia, Brazil. RESULTS: Of the EAEC markers that were tested, only EAEC heat-stable toxin (EAST1), protein involved in colonization (Pic), and the CVD432 sequence showed positive correlation with diarrhea; however, these virulence traits presented associations with distinct clinical characteristics. Although CVD432-positive strains were associated with persistent diarrhea, EAST1-positive strains were statistically correlated with acute diarrhea only in children >6 months of age. Typical EAEC strains were found with equal frequency in case patients and control subjects. O antigens of enteropathogenic E. coli (EPEC) were also sought, and the data showed that the EAEC markers are frequently segregated into 3 EPEC serogroups: O126, O128, and O158. CONCLUSIONS: The presence of EPEC O antigens along with EAEC markers influenced the positive association of E. coli strains with diarrhea. Concerning the detection of the AA phenotype, the CVD432 sequence presented a low positive predictive value, regardless of its high specificity as a marker.
Authors: Stephanie M Brandt; Nicola King; Angela J Cornelius; Aruni Premaratne; Thomas E Besser; Stephen L W On Journal: Appl Environ Microbiol Date: 2011-02-04 Impact factor: 4.792
Authors: Ila Fernanda Nunes Lima; Nadia Boisen; Josiane da Quetz Silva; Alexandre Havt; Eunice Bobo de Carvalho; Alberto Melo Soares; Noélia Leal Lima; Rosa Maria Salani Mota; James P Nataro; Richard Littleton Guerrant; Aldo Ângelo Moreira Lima Journal: J Med Microbiol Date: 2013-02-21 Impact factor: 2.472