[Frequency and Characterization of EPEC and EAggEC Isolated in Kawasaki City]

Thirty isolates of enteropathogenic Escherichia coli (EPEC) and 32 isolates of enteroaggregative E. coli (EAggEC) were isolated from 1,029 stool samples collected from Spring 2012 to December 2013 in Kawasaki city with the polymerase chain reaction (PCR) method targeting eae and aggR genes. Among the 30 EPEC and 32 EAggEC isolates, only 9 strains of EPEC and 8 strains of EAggEC were typed with the commercial O-antisera, whereas the majority of strains were untypable. However, several O-untypable EPEC and EAggEC strains were suggested to harbor the same O-antigen because of the detection of several examples of the same H-antigen. Analysis of the HEp-2 cell adherence test showed positive for only 2 strains (6.6%) of 30 EPEC isolates, meanwhile it showed positive for 16 strains (50.0%) of 32 EAggEC isolates. From these data, we concluded that EAggEC might be more virulent than EPEC, although both EAggEC and EPEC were isolated with almost similar rates from collected stool specimens.