Objective The aim of this study was to investigate the phenotypic and molecular features of atypical enteropathogenic Escherichia coli (aEPEC) isolates in Maanshan city. Methods The phenotypic characteristics of aEPEC strains were analyzed by biochemical identification, serological typing and drug sensitivity test, and the molecular features were examined by 16s rDNA sequencing, virulence genes detection, eae gene subtyping and multilocus sequence typing (MLST). Results The biochemical identification showed that eight isolates were E.coli, but one strain producing H2S couldn't be determined. One isolate was O26:K60, while the other strains were untypable by serological typing. For antimicrobial susceptibility, all of the 9 strains were sensitive to the antimicrobials tested, of them,4 strains were resistant to ampicillin and 2 strains were resistant to ampicillin/sulbactam and SMZ. The sequencing analysis of 16s rDNA genes showed that all of the 9 strains were E.coli. All 9 strains were uidA+, eae+, stx1- and stx2-. Four aEPEC strains were non-typable for intimin and five intimin subtypes (β1, β2, ε, ι1 and ι2) were identified in the other five strains. Altogether, 6 different STs were identified. Conclusion A high degree of heterogeneity of molecular features was observed among the aEPEC isolates in Maanshan city.
Key words
aEPEC /
Virulence gene /
Eae gene subtyping /
MLST
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