title: Assessment of a real-time PCR for the detection and characterization of verocytotoxigenic Escherichia coli.
abstract: The European Union Reference Laboratory (EU-RL) has produced guidelines for a real-time PCR for the detection of verocytotoxigenic Escherichia coli (VTEC). In this study, we validated the EU-RL assay on 545 strains of VTEC and evaluated the utility of the assay for the detection of VTEC from stool specimens. The validation study on cultures showed that the EU-RL VTEC PCR was 99.3% sensitive for the detection of vtx genes; only strains harbouring vtx2f genes were not detected. The assay was 100% sensitive and 100% specific for the detection of both the eae and O157 rfbE genes. In a prospective study involving 500 stool samples, the EU-RL VTEC PCR detected vtx genes in 12.4% of specimens, compared to 3.8% specimens found to be culture-positive for E. coli O157 using the Health Protection Agency national standard culture method. This study showed that the EU-RL VTEC assay was reliable and robust, and an effective rapid screening method for the detection of VTEC from stool specimens.
authors.affiliation: Microbiology Services Colindale, Health Protection Agency, 61 Colindale Avenue, London NW9 5HT, UK.
authors.forename: Claire
authors.initials: C
authors.lastname: Jenkins
authors.affiliation: Microbiology Services Colindale, Health Protection Agency, 61 Colindale Avenue, London NW9 5HT, UK.
authors.forename: Andy J
authors.initials: AJ
authors.lastname: Lawson
authors.affiliation: Microbiology Services Colindale, Health Protection Agency, 61 Colindale Avenue, London NW9 5HT, UK.
authors.forename: Tom
authors.initials: T
authors.lastname: Cheasty
authors.affiliation: Microbiology Services Colindale, Health Protection Agency, 61 Colindale Avenue, London NW9 5HT, UK.
authors.forename: Geraldine A
authors.initials: GA
authors.lastname: Willshaw
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics; D001431:Bacteriological Techniques / Q000379:methods*; D002238:Carbohydrate Epimerases / Q000235:genetics; D004927:Escherichia coli Infections / Q000175:diagnosis* / Q000382:microbiology*; D029968:Escherichia coli Proteins / Q000235:genetics; D005062:European Union; D005243:Feces / Q000382:microbiology; D017408:Guidelines as Topic; D006801:Humans; D008403:Mass Screening / Q000379:methods; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D011446:Prospective Studies; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D022603:Shiga Toxins / Q000235:genetics; D054323:Shiga-Toxigenic Escherichia coli / Q000235:genetics / Q000302:isolation & purification*; D000637:Transaminases / Q000235:genetics
chemical_list: D018829:Adhesins, Bacterial; D029968:Escherichia coli Proteins; D022603:Shiga Toxins; C073819:eaeA protein, E coli; D000637:Transaminases; D002238:Carbohydrate Epimerases; C061272:perosamine synthetase