Tonino Sofia

First Report of Capsule Replacement among Electrophoretic Type 37 Neisseria meningitidis Strains in Italy

ABSTRACT This report describes the C-to-B capsular switching in four Neisseria meningitidis strains belonging to the electrophoretic type 37 (ET-37) complex. In particular, one strain belonged to the new sequence type 1860, which was first detected in the year 2000 in Italy and is now frequently isolated. The presence of switched serogroup B strains deserves special attention if they prove as able to spread as their serogroup C progenitors belonging to the hypervirulent ET-37 complex.

Presence of Multiple Copies of the Capsulation b Locus in Invasive Haemophilus influenzae Type b (Hib) Strains Isolated from Children with Hib Conjugate Vaccine Failure

Most invasive Haemophilus influenzae type b strains possess a duplication of the capsulation locus. Further amplification resulting in as many as 5 copies has been described. To verify whether amplification is involved in vaccine failure, the number of copies of the locus was determined by Southern blotting in 90 strains from children with true vaccine failure (TVF) between 1993 and 1999 and in 139 strains from unvaccinated children (50 collected between 1993 and 1999 and 89 collected between 1991 and 1992, before routine immunization was introduced). A significantly greater proportion of strains from TVFs contained multiple copies, compared with strains from control children (24% vs. 10%; P = .0379), which suggests that amplification of the capb locus may be a contributory factor in vaccine failure. The presence of multiple-copy strains was associated with disease other than meningitis.

Serotype Distribution, Antibiotic Susceptibility, and Genetic Relatedness of Neisseria meningitidis Strains Recently Isolated in Italy

The availability of new polysaccharide-protein conjugate vaccines against Neisseria meningitidis serogroup C prompted European National Health authorities to carefully monitor isolate characteristics. In Italy, during 1999-2001, the average incidence was 0.4 cases per 100,000 inhabitants. Serogroup B was predominant and accounted for 75% of the isolates, followed by serogroup C with 24%. Serogroup C was isolated almost twice as frequently in cases of septicemia than in cases of meningitis, and the most common phenotypes were C:2a:P1.5 and C:2b:P1.5. Among serogroup B meningococci, the trend of predominant phenotypes has changed from year to year, with a recent increase in the frequency of B:15:P1.4. Only a few meningococci had decreased susceptibility to penicillin, and, in the penA gene, all of these strains had exogenous DNA blocks deriving from the DNA of commensal Neisseria flavescens, Neisseria cinerea, and Neisseria perflava/sicca. Fluorescent amplified fragment-length polymorphism analysis revealed the nonclonal nature of the strains with decreased susceptibility to penicillin.

Emergence in Italy of a Neisseria meningitidis Clone with Decreased Susceptibility to Penicillin

ABSTRACT A rise in invasive diseases due to Neisseria meningitidis C:2b:P1.5 with decreased penicillin susceptibility occurred in Italy during the last 2 years. Real-time PCR identified the Peni phenotype, and the penA sequence revealed the mosaicism of the gene. Molecular analyses assigned the isolates to a single emergent clone of the hypervirulent A4 cluster.

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

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.

Genetic Diversity of Invasive Strains of Haemophilus influenzae Type b before and after Introduction of the Conjugate Vaccine in Italy

We determined the genotypes of 95 invasive Haemophilus influenzae type b (Hib) strains collected before and after introduction of widespread Hib vaccination in Italy. No substantial change in genetic diversity was highlighted by pulsed-field gel electrophoresis. However, an upward temporal trend in proportion of strains possessing multiple copies of the capsulation b locus was detected (P = .03).

Neisseria meningitidis serogroup X sequence type 2888, Italy.

To the Editor: Neisseria meningitidis serogroup X was first described in the 1960s and has been found to be responsible of rare cases of invasive meningococcal diseases, in particular, meningitis, in North America, Europe, Australia, Africa, and the People’s Republic of China (1–3). This serogroup has recently emerged in Africa as an increasing cause of meningitis; unfortunately, it is not covered by current vaccine programs. Serogroup X outbreaks have been reported in Niger, Ghana, and Kenya (4–6). In particular, in Niger during January–June 2006, N. meningitidis serogroup X represented 51% of confirmed cases of meningitis (4). To investigate the population structure of serogroup X meningococci isolated during recent decades in Africa, Europe, and North America, Gagneux et al. (1) compared the molecular characteristics among them. That study highlighted a low genetic variability between African serogroup X strains, which contrasts with higher genetic variability among isolates from Europe and the United States (1). We describe a case of invasive meningococcal disease caused by a serogroup X N. meningitidis strain isolated in Italy. The patient was a 55-year-old Italian woman with no immune deficiency. The onset of disease started quickly with high fever (39°C) on June 1, 2009. No contacts with persons coming from abroad were reported. This case was diagnosed on the basis of clinical signs and symptoms and results of laboratory confirmatory tests, including blood culture. The patient received ceftriaxone (2 g/day) for 7 days with a favorable outcome. The strain was susceptible to penicillin G, rifampin, ciprofloxacin, and ceftriaxone, as determined by Etest method (bioMerieux, Florence, Italy). The breakpoints were those recommended by the Clinical and Laboratory Standards Institute (7). Serogroup was determined by serum agglutination, and serotype/subtype, NT:P1.15, 19 were determined by standard whole-cell ELISA with monoclonal antibodies (obtained from the National Institute for Biological Standards and Control, South Mimms, UK) (8). PorA variable regions, FetA, and multilocus sequence typing analyses were performed according to standard procedures from the Neisseria Multi Locus Sequence Typing Web site (http://pubmlst.org/neisseria). The isolate from Italy had the pattern PorA VR1–19, VR2–15, and VR3–36; F5–5 and sequence type (ST)-2888. The same ST was already described in Greece in 2002 but in a noninvasive strain (http://pubmlst.org/neisseria). The pattern obtained by pulsed-field gel electrophoresis (9), using the rare-cutting enzyme NheI, (data not shown), was identical to patterns found among meningococci X strains isolated in United Kingdom and belonging to ST-750, clonal group X-II (1). In particular, ST-2888 resembles, except for gdh gene sequence, ST-2317, which was found among the X meningococci isolated in the United Kingdom in 2002 with phenotype X:4:P1.7 (http://pubmlst.org/neisseria). Our data document a rare case of invasive meningococcal meningitis in Italy, caused by N. meningitidis serogroup X ST-2888. Future surveillance data may be able to determine epidemiologic influences, likely emanating from nearby countries, on the spread of such a strain into Italy.