DNA fingerprinting of Escherichia coli O157:H7 strains by pulsed-field gel electrophoresis.
Pulsed-field gel electrophoresis of genomic DNA was carried out on Escherichia coli O157:H7 strains from different geographic locations to determine its value in an epidemiological survey of O157 infections. Pulsed-field gel electrophoresis of XbaI-digested DNA fragments clearly separated E. coli O157:H7 strains from nontoxigenic E. coli O157:H19, O157:H43, and O157:H45 strains and from Shiga-like-toxin-producing E. coli strains of other serogroups. However, among the E. coli O157:H7 strains, the restriction patterns either were identical or differed only by a few fragment bands. In some cases, it was therefore impossible to distinguish among epidemiologically unrelated strains. Hybridization experiments with a DNA probe complementary to Shiga-like toxin II sequences revealed that the Shiga-like toxin II genes were located on DNA fragments of different lengths. Our data show that for a single highly conserved clone, such as E. coli O157:H7, other typing techniques may need to be performed in addition to DNA fingerprinting in epidemiological surveys.
Böhm
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Institut für Hygiene und Mikrobiologie, Universität Würzburg, Germany.
Karch
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D001427:Bacterial Toxins / Q000235:genetics; D015373:Bacterial Typing Techniques; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D005069:Evaluation Studies as Topic; D005798:Genes, Bacterial; D006801:Humans; D022622:Shiga Toxin 1; D022641:Shiga Toxin 2
D001427:Bacterial Toxins; D004269:DNA, Bacterial; D022622:Shiga Toxin 1; D022641:Shiga Toxin 2