The polymerase chain reaction: an epidemiological tool to differentiate between two clusters of pathogenicYersinia enterocoliticastrains

Abstract

A primer set designed to amplify the enterotoxin (yst) gene of pathogenic Yersinia enterocolitica strains generated two different electrophoretic profiles of the target sequence when a collection of strains of worldwide origin was screened. Serovars O : 1,3; O : 2a,3; O : 3; O : 5,27 and O : 9, known as European strains, produced a 200‐bp fragment that matched the size of the target sequence. However, serovars O : 4,32; O : 8; O : 13a,13b; O : 20 and O : 21, known as American strains, generated two fragments of 1.4 and 1.6 kb. The amplified products of one American strain were sequenced and the presence of the yst gene was confirmed in both fragments. Thus, the potential of the polymerase chain reaction to be used as an epidemiological tool in differentiation between two clusters of pathogenic strains of Y. enterocolitica could be demonstrated.

A universal protocol for PCR detection of 13 species of foodborne pathogens in foods

“…Many procedures have been used to remove in a boiling water bath for 5 min, then immediately cooled in the interference and inhibitors, such as DNA isolation and ice water. A 2 ml portion of each sample was added to 23 ml purification methods (Ibrahim et al 1992;Tsai et al 1993; of PCR mixture containing 50 mmol l -1 Tris-HCl (pH 8 · 5), Song et al 1993;Lantz et al 1994;Bulte et al 1995), enrich-20 mmol l -1 KCl, 3 mmol l -1 MgCl 2, 0 · 05% bovine serum ment culture with or without DNA isolation steps (Wernars albumin (BSA, No. A-4378, Sigma Chemical Co., St Louis, et al 1991;Read et al 1992;Koch et al 1993; Stone et MO, USA), 0·25 mmol l -1 of each of dATP, dTTP, dCTP, al.…”