Virulence factors of Escherichia coli strains belonging to serogroups O127 and O142

A total of 102 Escherichia coli strains belonging to serogroups O127 and O142 were examined for genotypic and phenotypic characteristics. The most frequent serotypes found were O127:H21, O127:H40 and O142:H34. The virulence properties were evaluated by adhesion to HeLa cells and hybridization with gene probes for diarrhoeagenic E. coli. Most strains in the two serogroups were categorized as enteropathogenic E. coli, but enteroaggregative E. coli was also detected in both serogroups. All strains that carried the eae sequence presented the LEE region inserted in selC. Five ribotypes were detected in serogroup O127 and four in serogroup O142 and a correlation between serotypes and ribotypes was observed mainly in serogroup O142.