EN
The aim of the study was to develop multiplex PCR (mPCR) assays which allow identification of shigatoxigenic Escherichia coli (STEC) strains and a characterization of their virulence properties. As an internal control, a fragment of 16S rRNA gene - two amplicons of 230 bp (stx gene) and 401 bp (16S rRNA) were obtained in the test, designated as mPCR-1 for the amplification of the stx gene, characteristic for all known Shiga toxin variants. The mPCR-2 assay was developed to characterize the stx-positive bacterial colonies, which allowed the detection of Shiga toxin 1 and/or 2, the affiliation of STEC O157:H7 serotype (rfbO157 and fliCн₇ genes), and internal control, resulting in amplicons of 348 bp (stx1), 584 (stx2), 420 bp (rfbO157), 247 bp (fliCн₇) and 798 bp (16S rRNA). The detection of markers O26wzx, rfbO111 and rfbO113, typical for E. coli O26, O111 and O113, respectively, was performed with mPCR-3. The products of molecular masses 153, 406 and 593 bp were observed. All STEC’s were also tested using mPCR-4, for the presence of enterohemolysin (ehlyA) and intimin (eaeA) markers generating specific bands of 837 bp (eaeA gene), 534 bp (ehlyA) and 401 (16S rRNA). The mPCR assays developed allow STEC to be identified and characterized and may be used in routine diagnosis of these bacteria.