Detection of cytolethal distending toxin and other virulence characteristics of enteropathogenic Escherichia coli isolates from diarrheal patients in Republic of Korea.
Cytolethal distending toxins (CDTs) represent an emerging family of newly described bacterial products that are produced by a number of pathogens. The genes encoding these toxins have been identified as a cluster of three adjacent genes, cdtA, cdtB, and cdtC, plus 5 cdt genetic variants, designated as cdt-I, cdt-II, cdt-III, cdt-IV, and cdt- V, have been identified to date. In this study, a general multiplex PCR system designed to detect Escherichia coli cdts was applied to investigate the presence of cdt genes among isolates. As a result, among 366 E. coli strains, 2.7% were found to carry the cdtB gene. In addition, the use of type-specific primers revealed the presence of cdt-I, cdtIV, and cdt-V types of the cdt gene, yet no cdt-II or cdt- III strains. The presence of other virulence genes (stx1, stx2, eae, bfp, espA, espB, and espD) was also investigated using a PCR assay. Among the 10 cdtB gene-positive strains, 8 were identified as CDT-producing typical enteropathogenic E. coli (EPEC) strains (eae(+), bfp(+)), whereas 2 were identified as CDT-producing atypical EPEC strains (eae(+), bfp(-)). When comparing the cytotoxic activity of the CDT-producing typical and atypical EPEC strains, the CDT-producing atypical EPEC strains appeared to be less toxic than the CDT-producing typical EPEC strains.
Kim
Jong-Hyun
JH
Division of Enteric Bacterial Infections, Center for Infectious Diseases, National Institute of Health, Seoul 122-701, Korea.
Kim
Jong-Chul
JC
Choo
Yun-Ae
YA
Jang
Hyun-Chul
HC
Choi
Yeon-Hwa
YH
Chung
Jae-Keun
JK
Cho
Seung-Hak
SH
Park
Mi-Seon
MS
Lee
Bok-Kwon
BK
D000818:Animals; D001427:Bacterial Toxins / Q000235:genetics*; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D003967:Diarrhea / Q000382:microbiology*; D054308:Enteropathogenic Escherichia coli / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000382:microbiology* / Q000503:physiopathology; D010861:Fimbriae, Bacterial / Q000235:genetics; D006801:Humans; D007723:Korea; D005810:Multigene Family; D016133:Polymerase Chain Reaction; D012703:Serotyping; D014774:Virulence; D037521:Virulence Factors / Q000032:analysis / Q000235:genetics
D001427:Bacterial Toxins; D004269:DNA, Bacterial; D037521:Virulence Factors; C067044:cytolethal distending toxin