title: Epidemiological and Molecular Characterization of Invasive Meningococcal Disease in Italy, 2008/09-2012/13.
abstract: BACKGROUND
  Following the introduction of meningococcal serogroup C conjugate vaccine in Italy in 2005, changes in the epidemiology of Invasive Meningococcal Disease (IMD) were expected. The study aims were to describe the epidemiological trend and to characterize the isolates collected during the period 2008/09-2012/13 by multilocus sequence typing (MLST). Data on laboratory confirmed meningococcal diseases from National Surveillance System of IMD were reported.
  
  
  METHODS
  Poisson regression models were used to estimate the incidence rate over time. Serogrouping and MLST were performed following published methods.
  
  
  RESULTS
  The incidence rate of laboratory confirmed meningococcal disease decreased from 0.33 per 100,000 population in 2008/09 to 0.25 per 100,000 population in 2012/13. The serogroup B incidence rate was significantly higher (p<0.01) than that of other serogroups, among all age groups. The significant decrease of the IMD incidence rate (p = 0.01) reflects the decrease of serogroup B and C, in particular among individuals aged 15-24 years old (p<0.01). On the other hand, serogroup Y incidence increased during the period (from 0.01/100,000 in 2008/09 to 0.02/100,000 in 2012/13, p = 0.05). Molecular characterizations revealed that ST-41/44 cc and ST-11 cc were the main clonal complexes identified among serogroup B and C isolates, respectively. In particular, ST-41/44 cc was predominant in all age groups, whereas ST-11 cc was not identified in infants less than 1 year of age.
  
  
  CONCLUSIONS
  IMD incidence declined in Italy and serogroup B caused most of the IMD cases, with infants having the highest risk of disease. Continued surveillance is needed to provide information concerning further changes in circulating meningococci with special regard to serogroup distribution. Moreover, knowledge of meningococcal genotypes is essential to detect hyper-invasive strains.
authors.affiliation: Department of Infectious, Parasitic & Immuno-mediated Diseases, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Arianna
authors.initials: A
authors.lastname: Neri
authors.affiliation: Department of Infectious, Parasitic & Immuno-mediated Diseases, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Patrizio
authors.initials: P
authors.lastname: Pezzotti
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.affiliation: Department of Infectious, Parasitic & Immuno-mediated Diseases, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Vacca
authors.affiliation: National Center for Epidemiology, Surveillance and Health Promotion, Istituto Superiore di Sanità, Roma, Italy.
authors.forename: Fortunato Paolo
authors.initials: FP
authors.lastname: D'Ancona
authors.affiliation: National Center for Epidemiology, Surveillance and Health Promotion, Istituto Superiore di Sanità, Roma, Italy.
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Caporali
authors.affiliation: Department of Infectious, Parasitic & Immuno-mediated Diseases, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Stefanelli
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007558:Italy / Q000453:epidemiology; D008297:Male; D008589:Meningococcal Infections / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control*; D022401:Meningococcal Vaccines / Q000627:therapeutic use*; D058885:Multilocus Sequence Typing; D009345:Neisseria meningitidis / Q000235:genetics* / Q000302:isolation & purification*; D065288:Serogroup; D012703:Serotyping; D055815:Young Adult
chemical_list: D022401:Meningococcal Vaccines; C410218:serogroup C meningococcal conjugate vaccine