Detection of the Escherichia coli group 2 polysaccharide capsule synthesis Gene kpsM by a rapid and specific PCR-based assay.

A rapid and simple PCR-based assay for detection of the group 2 capsule synthesis gene kpsM of Escherichia coli was designed and validated. When combined with the published group 2 primers (kpsIIf, 5'-GCGCATTTGCTGATACTGTTG-3'; kpsIIr, 5'-CATCCAGACGATAAGCATGAGCA-3'), the new primers (the kpsIIf primer and a new reverse primer K2r, 5'-AGGTAGTTCAGACTCACACCT-3') allowed specific identification by exclusion of the heretofore elusive K2 kpsM variant. The primers yielded the predicted amplicon when multiplexed with other primers and used under varied assay conditions, including a range of concentrations of individual reaction mixture ingredients and of annealing temperatures (from 54 to 64 degrees C).