Korean J Infect Dis.  2001 Apr;33(2):97-103.

Rapid Molecular Detection of Escherichia coli O157:H7

Affiliations
  • 1Department of Internal Medicine, College of Medicine, Chungbuk National University, Cheongju, Korea.
  • 2Department of Clinical Pathology, College of Medicine, Chungbuk National University, Cheongju, Korea.

Abstract

BACKGROUND: Sorbitol fermenting Escherichia coli O157 were reported. And E. coli O157:H7 produce various Shiga toxin (Stx) such as Stx1, Stx2, or variants of Stx2. In this study, we tried to establish laboratory methods that detect E. coli O157:H7 quickly and precisely by analyzing sensitivity of colony hybridization test and PCR technique. METHODS: Stx1-producing E. coli ATCC 43890, Stx2-producing E. coli ATCC 43889, and Stx2vha- producing E. coli ATCC 51435 were tested. Three strains of E. coli were diluted with 0.1 g of diarrheal stools from 107 CFU to 101 CFU respectively. The stool samples were incubated overnight in MacConkey agar plates. A mean of 63 colonies were hybridized by stx1- and stx2-specific oligonucleotide probes. PCR for stx1 gene and stx2 gene was done after overnight- incubation of stool samples in the LB broth with vancomycin (6 ug/mL). Positive colonies by colony hybridization were confirmed by PCR for stx1 gene and stx2 gene. RESULTS: Colony hybridization test could detect Stx1-producing E. coli at 103 CFU per 0.1 g of stool, Stx2-producing E. coli at 105 CFU per 0.1 g of stool, and Stx2vha-producing E. coli at 104 CFU per 0.1 g of stool. PCR technique after enrichment in LB broth with vancomycin (6 ug/mL) could detect stx1-, stx2-, and stx2vha-containing E. coli at 10 CFU per 0.1 g of stool respectively. CONCLUSOIN: A combination of colony hybridization and PCR after enrichment in broth with vancomycin (6 ug/mL) is useful for the rapid and precise diagnosis of infections of Shiga toxin-producing E. coli O157:H7.

Keyword

Escherichia coli O157:H7; Colony Hybridization; Polymerase Chain Reaction

MeSH Terms

Agar
Diagnosis
Escherichia coli O157
Escherichia coli*
Escherichia*
Oligonucleotide Probes
Polymerase Chain Reaction
Shiga Toxin
Sorbitol
Vancomycin
Agar
Oligonucleotide Probes
Shiga Toxin
Sorbitol
Vancomycin
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