Characterization of fHbp , nhba ( gna2132 ), nadA , porA , Sequence Type (ST), and Genomic Presence of IS 1301 in Group B Meningococcal ST269 Clonal Complex Isolates from England and Wales

Abstract

Highly effective glycoconjugate vaccines exist against four of the five major pathogenic groups of meningococci: A, C, W-135, and Y. An equivalent vaccine against group B meningococci (menB) has remained elusive due to the poorly immunogenic capsular polysaccharide. A promising alternative, the investigational recombinant menB (rMenB)- outer membrane vesicle (OMV) vaccine, contains fHBP, NHBA (previously GNA2132), NadA, and outer membrane vesicles (OMVs) from the New Zealand MeNZB vaccine. MenB currently accounts for 90% of meningococcal disease in England and Wales, where the multilocus sequence type (ST) 269 (ST269) clonal complex (cc269) has recently expanded to account for a third of menB cases. To assess the potential cc269 coverage of the rMenB-OMV vaccine, English and Welsh cc269 isolates from the past decade were genetically characterized with respect to fHBP, NHBA, and NadA. All of the isolates harbored fHbp and nhba alleles, while 98% of the cc269 isolates were devoid of nadA . Subvariant profiling of fHbp , nhba , and porA against STs revealed the presence of two broadly distinct and well-defined clusters of isolates, centered around ST269 and ST275, respectively. An additional molecular marker, insertion sequence IS 1301 , was found to be present in 100% and 1301 within the ST269 cluster.