Serotype Distribution, Antibiotic Susceptibility, and Genetic Relatedness ofNeisseria meningitidisStrains Recently Isolated in Italy

Abstract

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.

Prediction of Decreased Susceptibility to Penicillin of Neisseria meningitidis Strains by Real-Time PCR

“…Interestingly, during the year 2002, a higher proportion of PenI meningococci was detected (26%), and the C:2b:P1.5 phenotype was predominant. Moreover, MICs for PenI strains were higher than those found in previous years (7). The phenotypic characteristics of all the strains examined are shown in Table 1.…”

“…In fact, a greater number of PenI strains were detected for which MICs were higher than those found in previous years. A unique clone, C:2b:P1.5, belonging to the ST8/A4 cluster, accounted for 38% of PenI strains isolated in 2002, marking a change in the situation previously observed in Italy (7).…”

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

“…In Italy, a situation of low endemicity (0.4 case per 100,000 inhabitants) was characterized by the predominance of serogroup B and the presence of a large number of different phenotypes (12).…”

Neisseria meningitidisinfection: who, when and where?

“…In Italy, it is the second most common serogroup [100][101][102]. Ten IMD cases caused by this serogroup occurred in northern Italy in 2007 and 2008.…”

“…They were of national relevance due to the severity and high CFR; six cases were fatal, and three of them died for fatal septicemia [100]. During 1999-2001, serogroup C accounted for 24% of 118 N. meningitidis cases of infection [101] and in 2011 for 16% [102]. In October 2012, four cases of IMD occurred on a cruise ship that was sailing along the Italian coast.…”