Polymorphism in the 157-bp primer/probe region among a strain, Y. pseudotuberculosis O:8, for which the region was amplified by using the real-time PCR developed in this study, and Y. pseudotuberculosis O:11 (and O:12), which was not amplified by using the real-time PCR. Highlights: gray background = primers, black background = MGB probe, underline = TAMRA probe, bold/italic = nucleotide variants in serotypes O:11 (and O:12) and other serotypes, respectively.