Location: Meat Safety and QualityTitle: Use of new markers for precise detection of pathogenic Shiga toxin-producing Escherichia coli
|Bosilevac, Joseph - Mick|
|BUGAREL, MARIE - Biomerieux, Inc|
|MACHADO, MIGUEL - Biomerieux, Inc|
|CARRICO, JOAO - Biomerieux, Inc|
|CHABLAIN, PATRICE - Biomerieux, Inc|
|BRIESE, DEBORAH - Biomerieux, Inc|
|MURRAY, JOHN - Murray-Brown Laboratories, Inc|
|BAILEY, J. STAN - Biomerieux, Inc|
|DUTTA, VIKRANT - Biomerieux, Inc|
Submitted to: Journal of Food Protection
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2021
Publication Date: 7/18/2021
Citation: Bosilevac, J.M., Bugarel, M., Machado, M., Carrico, J.A., Chablain, P., Briese, D., Murray, J., Bailey, J., Dutta, V. 2021. Use of new markers for precise detection of pathogenic Shiga toxin-producing Escherichia coli. Journal of Food Protection. 84(Suppl A): P. 113-114.
Technical Abstract: Introduction: The USDA-FSIS has indicated that ~10% of samples that contain stx, eae, and a serogroup gene can be culture confirmed. Newly commercialized biomarkers (espK, espV and CRISPR_O26E) that are present in potentially pathogenic eae-positive STEC can reduce the number of non-culture confirmable PCR screening results and increase the reliability of STEC screening assays. Purpose: To evaluate the correlation between the presence of stx/eae genes from pathogenic STEC strains and the new biomarkers in STEC isolates, retrospective archived beef enrichments, and prospective beef enrichments from a service lab. Methods: Presence of stx and eae, and the biomarkers were determined using GENE-UP® EH1, and NM kits respectively. A panel of 96 E. coli isolated from cattle, beef, and human illness were tested on 1) freshly grown, 2) archived frozen stocks of the strains for the strain evaluation (total N=192). Prequalified (USDA MLG Ch5A&B/USMARC potential positive) archived beef enrichments (N=288) were used for retrospective analysis. Data from EH1 and NM was compared to the culture methods as a reference. Lastly, for a prospective analysis 45 samples were chosen to assess the prevalence and EH1 and NM correlation. Results: For strains, >98% (162/165) correlation was observed between NM-EHEC and EH1. The retrospective analysis indicated 15 samples with eae-positive STEC isolated, and 96 negative for non-pathogenic E. coli. Sensitivity and specificity for NM+EH1 was 100% and 98.9% with the overall accuracy of ~99% and a kappa coefficient of 0.96. In the prospective analysis, out of 45 samples, 12 were NM+EH1+, 4 EH1- NM+, and 29 were EH1-NM-. The prospective analysis is continuing to generate further data on the prevalence rate of stx, eae and NM in eae-positive STEC containing samples. Significance: EH1+NM kits can provide precise detection of eae-positive STEC, while reducing presumptive positives sample numbers and implicate less product for diversion.