Serogroup C meningococci in Italy in the era of conjugate menC vaccination

Abstract

BackgroundTo assess changes in the pattern of Invasive Meningococcal Disease (IMD) in Italy after the introduction of conjugate menC vaccine in the National Vaccine Plan 2005–2007 and to provide information for developing timely and appropriate public health interventions, analyses of microbiological features of isolates and clinical characteristics of patients have been carried out. In Italy, the number of serogroup C meningococci fell progressively following the introduction of the MenC conjugate vaccine, recommended by the Italian Ministry of Health but implemented according to different regional strategies.MethodsIMD cases from January 2005 through July 2008 reported to the National Meningococcal Surveillance System were considered for this study. Serogrouping and sero/subtyping were performed on 179 serogroup C strains received at the National Reference Laboratory of the Istituto Superiore di Sanità. Antibiotic susceptibility testing was possible for 157 isolates. MLST (Multilocus sequence typing), porA VRs (Variable Region) typing, PFGE (Pulsed Field Gel Electrophoresis), VNTR (Variable Number Tandem Repeats) analyses were performed on all C:2a and C:2b meningococci (n = 147), following standard procedures.ResultsIn 2005 and 2008, IMD showed an incidence of 0.5 and 0.3 per 100,000 inhabitants, respectively. While the incidence due to serogroup B remained stable, IMD incidence due to serogroup C has decreased since 2006. In particular, the decrease was significant among infants. C:2a and C:2b were the main serotypes, all C:2a strains belonged to ST-11 clonal complex and all C:2b to ST-8/A4. Clinical manifestations and outcome of infections underlined more severe disease caused by C:2a isolates. Two clusters due to C:2a/ST-11 meningococci were reported in the North of Italy in December 2007 and July 2008, respectively, with a high rate of septicaemia and fatal outcome.ConclusionPublic health surveillance of serogroup C invasive meningococcal disease and microbiological/molecular characterization of the isolates requires particular attention, since the hyper-invasive ST-11 predominantly affected adolescents and young adults for whom meningococcal vaccination was not recommended in the 2005–2007 National Vaccine Plan.

Genome-based study of a spatio-temporal cluster of invasive meningococcal disease due to Neisseria meningitidis serogroup C, clonal complex 11

“…Italy is considered a country at low incidence of invasive meningococcal disease (IMD), with predominance of the meningococcal B and C capsular serogroups. 1 However, IMD cases due to serogroup C (MenC) declined after vaccine introduction 2 consistently with the trends observed in other EU countries. 3e7 In Italy, the use of the meningococcal C conjugate (MCC) vaccine for children 13-to-15 month olds and for adolescents 11-to-18 year-olds was recommended by the Italian National Immunization Plan for the years 2012/2014.…”

Epidemiological and Molecular Characterization of Invasive Meningococcal Disease in Italy, 2008/09-2012/13

“…In Italy, IMD incidence rate showed cyclical fluctuations, in particular regarding to the total number of cases due to serogroup B and C, respectively [ 22 , 14 ]. Moreover, other factors such as climate and geographical variation have been associated to a gradient in the IMD incidence in the country [ 23 ].…”

“…In Italy, in a previous analysis IMD due to serogroup C meningococci affected mostly children less than 4 years of age and adolescents, [ 14 ], but now the serogroup B is highly predominant, [ 15 ].…”

Typing and surface charges of the variable loop regions of PorB from Neisseria meningitidis

“…A total of 35 invasive strains of N. meningitidis collected within the Italian National Surveillance System for Invasive Meningococcal Disease (IMD) were selected for this study: 15 serogroup B and 20 serogroup C, both belonging to the main hyperinvasive clonal complexes identified in the country .…”