Screening of food raw materials for the presence of Shiga toxin-producing Escherichia coli O91:H21

J. Madic (1) , C. Lecureuil (1) , F. Dilasser (1) , Sylviane Derzelle (2) , E. Jamet , P. Fach (1) , F. Auvray (1)

1 LERQAP - Laboratoire d'études et de recherches sur la qualité des aliments et sur les procédés agroalimentaires
2 AFSSA - Agence Française de Sécurité Sanitaire des Aliments

Aims: To provide information on the prevalence and detection, in foods, of Shiga toxin-producing Escherichia coli (STEC) O91:H21. Methods and Results: Seven hundred fifteen minced beef meats and 205 raw milk samples were analysed by stx-specific PCR-ELISA. Samples positive for stx were subsequently tested for the presence of wzy-O91, fliC-H21 and the adhesin-encoding gene saa. For minced meat, 16 (2AE2%) and 11 (1AE5%) samples were found positive for (stx, wzy-O91, fliC-H21) and (stx, wzy-O91, fliC-H21, saa) combinations, respectively. For raw milk, seven (3AE4%) samples were found positive for the (stx, wzy-O91, fliC-H21) combination but none of these contained saa. Two STEC O91:H21 saa-positive strains and three STEC O91 H21-and saa-negative strains were isolated by colony hybridization. Conclusions: A low prevalence of potentially pathogenic STEC O91:H21 in food products was found using a combination of PCR assays targeting stx, wzy-O91, fliC-H21 and saa. Significance and Impact of the Study: The PCR-based approach described here represents a valuable method for rapid screening of food samples contaminated by STEC O91:H21.

Mots clés: atypical EHEC; E. coli; O91:H21; real-time PCR; saa; STEC; stx

Domaines: Ingénierie des aliments; Bactériologie

J. Madic, C. Lecureuil, F. Dilasser, Sylviane Derzelle, E. Jamet, et al.. Screening of food raw materials for the presence of Shiga toxin-producing Escherichia coli O91:H21. Letters in Applied Microbiology, 2009, 48 (4), pp.447-451. ⟨10.1111/j.1472-765X.2008.02549.x⟩. ⟨anses-03858050⟩