title: Genetic characteristics of Neisseria meningitidis serogroup B strains carried by adolescents living in Milan, Italy: implications for vaccine efficacy.
abstract: Before a protein vaccine is introduced into a country, it is essential to evaluate its potential impact and estimate its benefits and costs. The aim of this study was to determine the genetic characteristics of Neisseria meningitidis B (NmB) in the pharyngeal secretions of 1375 healthy adolescents aged 13-19 y living in Milan, Italy, in September 2012, and the possible protection offered by the two currently available NmB protein vaccines. Ninety-one subjects were Nm carriers (6.6%), 29 (31.9%) of whom carried the NmB capsular gene. The 29 identified strains belonged to eight clonal complexes (CCs), the majority of which were in the ST-41/44/Lin.3 CC (n = 11; 37.9%). All of the identified strains harboured ƒHbp alleles representing a total of 15 sub-variants: the gene for NHBA protein was found in all but three of the studied strains (10.3%) with 13 identified sub-variants. There were 15 porA sub-types, seven of which were identified in just one CC. The findings of this study seem to suggest that both of the protein vaccines proposed for the prevention of invasive disease due to NmB (the 4-protein and the 2-protein products) have a composition that can evoke a theoretically effective antibody response against the meningococcal strains currently carried by adolescents living in Northern Italy. The genetic characteristics of NmB strains can be easily evaluated by means of molecular methods, the results of which can provide an albeit approximate estimate of the degree of protection theoretically provided by the available vaccines, and the possible future need to change their composition.
authors.affiliation: Pediatric Clinic 1; Department of Pathophysiology and Transplantation; Università degli Studi di Milano; Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico; Milan, Italy.
authors.forename: Susanna
authors.initials: S
authors.lastname: Esposito
authors.forename: Alberto
authors.initials: A
authors.lastname: Zampiero
authors.forename: Leonardo
authors.initials: L
authors.lastname: Terranova
authors.forename: Valentina
authors.initials: V
authors.lastname: Montinaro
authors.forename: Alessia
authors.initials: A
authors.lastname: Scala
authors.forename: Valentina
authors.initials: V
authors.lastname: Ansuini
authors.forename: Nicola
authors.initials: N
authors.lastname: Principi
mesh_terms: D000293:Adolescent; D002353:Carrier State / Q000453:epidemiology* / Q000382:microbiology*; D005260:Female; D005838:Genotype; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008589:Meningococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D022401:Meningococcal Vaccines / Q000276:immunology*; D058889:Molecular Typing; D009305:Nasopharynx / Q000382:microbiology; D038541:Neisseria meningitidis, Serogroup B / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D055815:Young Adult
chemical_list: D022401:Meningococcal Vaccines
keywords: Neisseria meningitides; invasive bacterial disease; meningococcal vaccine; meningococcus B; meningococcus B vaccine