title: Persistent occurrence of serogroup Y/sequence type (ST)-23 complex invasive meningococcal disease among patients aged five to 14 years, Italy, 2007 to 2013.
abstract: In Italy, the incidence of invasive meningococcal disease (IMD) has remained stable since 2007 (around 0.3 cases/100,000 inhabitants). However, as reported for other European countries, an increase of serogroup Y Neisseria meningitidis has been observed. In this study we report IMD cases from 2007 to 2013 in Italy and investigate the clinical and epidemiological features of cases affected by serogroup Y. Molecular characteristics of serogroup Y strains are also described. During the study period, the proportion of IMD cases due to serogroup Y increased, ranging from 2% in 2007 to 17% in 2013 (odds ratio (OR): 8.8), whereby the five to 14 years age group was mostly affected (p < 0.001). Overall 81 serogroup Y IMD cases were identified, with a median age of 18 years, ranging from three months to 84 years. Of the 81 respective patient samples, 56 were further subject to molecular typing. The sequence type (ST)-23 complex (clonal complex (cc)23) was predominant among serogroup Y meningococci (54/56 samples), and included nine different STs. Presumably, ST-23 was the founding genotype, with all the other STs presenting as single-locus variants. All cc23 isolates analysed harboured mutations in the lpxL1 gene; however, no associations among lpxL1 mutations, ST and age group were identified. Overall, these findings generate scientific evidence for the use of the quadrivalent meningococcal conjugate vaccine in the five to 14 years age group.
authors.affiliation: Department of Infectious, Parasitic & Immuno-mediated Diseases, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Fazio
authors.forename: Arianna
authors.initials: A
authors.lastname: Neri
authors.forename: Giovanna
authors.initials: G
authors.lastname: Renna
authors.forename: Paola
authors.initials: P
authors.lastname: Vacca
authors.forename: Raffaele
authors.initials: R
authors.lastname: Antonetti
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Barbui
authors.forename: Laura
authors.initials: L
authors.lastname: Daprai
authors.forename: Paolo
authors.initials: P
authors.lastname: Lanzafame
authors.forename: Lucia
authors.initials: L
authors.lastname: Rossi
authors.forename: Iolanda
authors.initials: I
authors.lastname: Santino
authors.forename: Carlo
authors.initials: C
authors.lastname: Tascini
authors.forename: Caterina
authors.initials: C
authors.lastname: Vocale
authors.forename: Paola
authors.initials: P
authors.lastname: Stefanelli
mesh_terms: D000217:Acyltransferases / Q000235:genetics; D000293:Adolescent; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D005260:Female; D005838:Genotype; D006801:Humans; D015994:Incidence; D007558:Italy / Q000453:epidemiology; D008297:Male; D008589:Meningococcal Infections / Q000175:diagnosis* / Q000453:epidemiology* / Q000235:genetics; D058889:Molecular Typing; D038581:Neisseria meningitidis, Serogroup Y / Q000235:genetics* / Q000302:isolation & purification; D018272:Porins / Q000235:genetics; D012703:Serotyping
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; C093120:FrpB protein, bacteria; D018272:Porins; C057699:porin protein, Neisseria; D000217:Acyltransferases; C118473:LpxL protein, bacteria
keywords: ST-23 complex; meningococcus; serogroup Y