Development of a multiplex PCR assay for identification of Klebsiella pneumoniae hypervirulent clones of capsular serotype K2.

Hypervirulent Klebsiella pneumoniae isolates of capsular serotype K2 (hvKP-K2) that cause community-acquired invasive infections represent several unrelated clones, which all belong to phylogenetic group KpI. These clones can be recognized using multilocus sequence typing and genomic analyses, but no rapid method currently exists to differentiate them. In this work, a multiplex PCR assay was developed to identify three hvKP-K2 groups: (i) sequence type (ST)86; (ii) ST380 and ST679 (i.e. clonal group 380); and (iii) ST65 and ST375. A specific genetic marker, Kp50233, allowing K. pneumoniae sensu stricto (corresponding to phylogroup KpI) to be distinguished from closely related species, was included in the assay. This PCR assay will be useful in better defining the epidemiology and clinical features of emerging virulent K. pneumoniae clones.