Use of commercial enzyme immunoassays and immunomagnetic separation systems for detecting Escherichia coli O157 in bovine fecal samples

A commercial enzyme immunoassay (EIA) (E. coli O157 Visual Immunoassay; Tecra Diagnostics) performed on enrichment cultures in modified Escherichia coli broth (mECn) was compared with immunomagnetic separation (IMS) (Dynabeads anti-E. coli O157; Dynal) performed on enrichment cultures in modified buffered peptone water (BPW-VCC) for the detection of E. coli O157 in bovine fecal samples. Tests on fecal suspensions inoculated with each of 12 different strains of E. coli O157 showed that both the EIA and IMS methods were 10- to 100-fold more sensitive than direct culture or enrichment subculture methods for detection of the organism. EIA and IMS were then compared for detection of E. coli O157 in bovine rectal swabs. For confirmation of positive EIA tests, a commercial system (Immunocapture System [ICS]; Tecra Diagnostics) was compared with IMS; both were performed on mECn enrichment cultures. Of 200 rectal swabs examined, 17 gave positive results in the EIA which were confirmed by both confirmation systems, 2 gave positive results in the EIA which were confirmed by IMS but not by ICS, and 1 gave a positive result in the EIA which was confirmed by ICS but not by IMS. Of these 20, 15 were also positive by the BPW-VCC-IMS culture system; a further 3 samples were positive by this culture system but gave a negative result in the EIA. Eight samples were negative by the BPW-VCC-IMS culture system but gave a positive result in the EIA which could not be confirmed by either confirmation system. Further examination of the eight unconfirmed EIA-positive samples yielded sorbitol-fermenting E. coli O157 from three samples. Of the remaining five cultures, four were positive in an EIA for verocytotoxins (VT) and two were positive in a cell culture assay for VT1. The remaining 170 samples were negative by both EIA and BPW-VCC-IMS. The Tecra EIA and IMS are both technically simple and sensitive methods for detecting E. coli O157 in bovine fecal samples. There was no statistically significant difference between the numbers of positives detected by the different assays (P = 0.29).

[1]  Q. Mcnemar.  Note on the sampling error of the difference between correlated proportions or percentages , 1947, Psychometrika.

[2]  M. Doyle,et al.  Survival and growth characteristics of Escherichia coli associated with hemorrhagic colitis , 1984, Applied and environmental microbiology.

[3]  H. O. Lancaster,et al.  Significance Tests in Discrete Distributions , 1961 .

[4]  V. Gannon,et al.  Rapid and sensitive method for detection of Shiga-like toxin-producing Escherichia coli in ground beef using the polymerase chain reaction , 1992, Applied and environmental microbiology.

[5]  M. Louie,et al.  Cloning and nucleotide sequence of the eae gene homologue from enterohemorrhagic Escherichia coli serotype O157:H7 , 1992 .

[6]  B. Synge,et al.  Verotoxigenic Escherichia coli 0.157 in Scottish calves , 1992, Veterinary Record.

[7]  J. Wells,et al.  A statewide outbreak of Escherichia coli O157:H7 infections in Washington State. , 1990, American journal of epidemiology.

[8]  B T Butman,et al.  Detection of Escherichia coli O157:H7 in meat by an enzyme-linked immunosorbent assay, EHEC-Tek , 1995, Applied and environmental microbiology.

[9]  E. Todd,et al.  Increased sensitivity of the rapid hydrophobic grid membrane filter enzyme-labeled antibody procedure for Escherichia coli O157 detection in foods and bovine feces , 1990, Applied and environmental microbiology.

[10]  M. Doyle,et al.  Isolation of Escherichia coli O157:H7 from retail fresh meats and poultry , 1987, Applied and environmental microbiology.

[11]  C. Daly,et al.  Evaluation of non-radioactive trivalent DNA probe (LT, ST1a, ST1b) for detecting enterotoxigenic Escherichia coli. , 1993, Journal of clinical pathology.

[12]  C. Siddons,et al.  Use of tellurite for the selection of verocytotoxigenic Escherichia coli O157. , 1993, Journal of medical microbiology.

[13]  R. Tauxe,et al.  ISOLATION OF ESCHERICHIA COLI 0157:H7 FROM DAIRY CATTLE ASSOCIATED WITH TWO CASES OF HAEMOLYTIC URAEMIC SYNDROME , 1986, The Lancet.

[14]  H. Lior,et al.  Prevalence of verocytotoxigenic Escherichia coli in ground beef, pork, and chicken in southwestern Ontario , 1990, Epidemiology and Infection.

[15]  H. Lior,et al.  Isolation of verocytotoxin-producing Escherichia coli from milk filters in south-western Ontario , 1989, Epidemiology and Infection.

[16]  C. Siddons,et al.  An improved selective medium for the isolation of Escherichia coli O157. , 1991, Journal of medical microbiology.

[17]  P. Chapman,et al.  Verotoxin-producing Escherichia coli infections in Sheffield: cattle as a possible source , 1989, Epidemiology and Infection.

[18]  S. Ratnam,et al.  Sorbitol-MacConkey medium for detection of Escherichia coli O157:H7 associated with hemorrhagic colitis , 1986, Journal of clinical microbiology.

[19]  Chapman Pa.  Purification of the verotoxins of Escherichia coli and production of antitoxins for use in a diagnostic test. , 1993 .

[20]  李幼升,et al.  Ph , 1989 .

[21]  C. Siddons,et al.  A comparison of immunomagnetic separation and direct culture for the isolation of verocytotoxin-producing Escherichia coli O157 from cases of bloody diarrhoea, non-bloody diarrhoea and asymptomatic contacts. , 1996, Journal of medical microbiology.

[22]  J. Fox,et al.  Cattle as a possible source of verocytotoxin-producing Escherichia coli O157 infections in man , 1993, Epidemiology and Infection.

[23]  J. Wells,et al.  Hemorrhagic colitis associated with a rare Escherichia coli serotype. , 1983, The New England journal of medicine.

[24]  C. Siddons,et al.  Immunomagnetic separation as a sensitive method for isolating Escherichia coli O157 from food samples , 1994, Epidemiology and Infection.

[25]  R. Salmon,et al.  Vero cytotoxin‐producing Escherichia coli O157 in beefburgers linked to an outbreak of diarrhoea, haemorrhagic colitis and haemolytic uraemic syndrome in Britain , 1994, Letters in applied microbiology.

[26]  H. Karch,et al.  A biotyping scheme for Shiga-like (Vero) toxin-producing Escherichia coli O157 and a list of serological cross-reactions between O157 and other gram-negative bacteria. , 1992, Zentralblatt fur Bakteriologie : international journal of medical microbiology.

[27]  J. Matches,et al.  Temperature range for growth of Escherichia coli serotype O157:H7 and selected coliforms in E. coli medium , 1990, Journal of clinical microbiology.

[28]  A. Borczyk,et al.  BOVINE RESERVOIR FOR VEROTOXIN-PRODUCING ESCHERICHIA COLI 0157:H7 , 1987, The Lancet.

[29]  R. Higgins,et al.  Untreated milk as a source of verotoxigenic E coli O157 , 1993, Veterinary Record.

[30]  J. H. Green,et al.  Isolation of Escherichia coli serotype O157:H7 and other Shiga-like-toxin-producing E. coli from dairy cattle , 1991, Journal of clinical microbiology.

[31]  C. Siddons,et al.  A comparison of immunomagnetic separation and direct culture for the isolation of verocytotoxin-producing Escherichia coli O157 from bovine faeces. , 1994, Journal of medical microbiology.