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′-GCGCATT TGCTGATACTGTTG-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°C).