Development of an allele-specific PCR for Escherichia coli B2 sub-typing, a rapid and easy to perform substitute of multilocus sequence typing

• An assay to type B2 E. coli strains at the sequence type complex level is described.
• The method is simple and based on the principle of allele-specific PCR.
• It allows an assignation of E. coli B2 bacteremia strains in 95% of the cases.

We developed and validated an allele-specific PCR method for detecting the nine main Escherichia coli phylogroup B2 lineages involved in extra-intestinal infections, which could be used as a substitute for multilocus sequence typing in studies for which the greater resolution at the sequence type level is not needed.