Monitoring the long-term molecular epidemiology of the pneumococcus and detection of potential 'vaccine escape' strains
Pandya GA, McEllistrem MC, Venepally P, Holmes MH, Jarrahi B, Sanka R, Liu J, Karamycheva SA, Bai Y, Fleischmann RD, Peterson SN
While the pneumococcal protein conjugate vaccines reduce the incidence in invasive pneumococcal disease (IPD), serotype replacement remains a major concern. Thus, serotype-independent protection with vaccines targeting virulence genes, such as PspA, have been pursued. PspA is comprised of diverse clades that arose through recombination. Therefore, multi-locus sequence typing (MLST)-defined clones could conceivably include strains from multiple PspA clades. As a result, a method is needed which can both monitor the long-term epidemiology of the pneumococcus among a large number of isolates, and analyze vaccine-candidate genes, such as pspA, for mutations and recombination events that could result in 'vaccine escape' strains.