Rapid identification and differentiation of clinical isolates of enteropathogenic Escherichia coli (EPEC), atypical EPEC, and Shiga toxin-producing Escherichia coli by a one-step multiplex PCR method

Abstract

Enteropathogenic Escherichia coli (EPEC), atypical enteropathogenic E. coli, and Shiga toxin-producing E. coli differ in their virulence factor profiles, clinical manifestations, and prognosis, and they require different therapeutic measures. We developed and evaluated a robust multiplex PCR to identify these pathogroups based on sequences complementary to escV, bfpB, stx1, and stx2.

FIG. 1.

Whole-cell multiplex-PCR pattern of reference strains EPEC E2348/69 (carrying LEE and the EAF plasmid but no stx genes), ATEC 3431-4/86 (carrying LEE, but lacking the EAF plasmid and stx), E. coli C600 (lacking LEE, the EAF plasmid and stx), uropathogenic E. coli KS52 (lacking LEE, the EAF plasmid and stx), STEC EDL933 (carrying LEE, stx₁ and stx₂, but lacking the EAF plasmid), and STEC 493/89 (carrying LEE and stx₂ but lacking the EAF plasmid). To identify the LEE pathogenicity island, we used primer pairs specifically for escV; for the EAF plasmid we designed primer pairs for the bfpB gene, and for the Shiga toxins (Stx) of STEC strains we used the primers MP2-stx1A-F/R and MP2-stx2A-F/R that correctly detected stx₁ and stx₂ and their variants stx_1c, stx_1d, stx_2c, stx_2d, and stx_2e.