J Korean Soc Microbiol.
1999 Jun;34(3):211-220.
Virulence Factors and Genotyping of Enterotoxigenic Escherichia coli O128 Isolates from Clinical Specimens
Abstract
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Sixteen strains of LT-producing enterotoxigenic E. coli 0128 which were isolated from diarrheal patient's stool in Pusan University Hospital, were serotyped and analyzed for plasmid DNA profile, MRHA of human blood cells, and also tested for possession of LT, ST, aggA, EAST1 genes by the PCR method and analyzed the RAPD pattern. Screening sensitivity for ETEC by salting out test was 87.5%. These data suggest that hydrophobicity test using salting out is rapid, inexpensive, and simple screening test for ETEC. CFAs were identified in 87.5% of strains; 43.75% the strains harbored CFA/I, 43.75% CFA/II, and 12.5% expressed none of these CFAs. For plasmid profiles, 12 strains had 60 MDa plasmid and several smaller plasmids. The strains showed 5 types of plasmid profiles. By PCR, LT gene but not ST gene was detected from all of the 16 strains EAST1 gene was detected from 14 strains. Ten strains could be differentiated to 3 patterns by chromosomal DNA fingerprint. The chromosomal DNA fingerprinting is considered very useful for the epidemiological study.