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Outbreaks of Neisseria meningitidis serogroup X meningococcal (MenX) infections in the African meningitis belt caused by isolates of clonal complex (CC) 181, including an outbreak in 2006 in Niger and [...]

Objectives: To evaluate and characterise meningococcal carriage among healthy men who have sex with men (MSM) within a screening programme for Neisseria gonorrhoeae infection at the San Gallicano Dermatological Institute, Italy.Methods: A total of 441 MSM attending the STI/HIV Centre of the San Gallicano Institute, Rome, Italy, in 2016 were routinely screened for N. gonorrhoeae infection by pharyngeal and rectal swabs. N. meningitidis isolates were evaluated for antibiotic susceptibility and characterised by whole genome sequencing. Genetic relationships among the meningococcal carriage isolates were determined using core genome multilocus sequence typing analysis. The soluble domain of AniA (sAniA) protein expression by western blotting was also evaluated.Results: A total of 62 (14.1%, 95% CI 11.1 to 17.6) carriage meningococci were found among 441 MSM. Forty-three viable N. meningitidis isolates were cultivated (42 from pharyngeal and 1 from rectal swabs). All the viable isolates were susceptible to cefotaxime, ceftriaxone, ciprofloxacin and rifampicin. Four isolates were penicillin G-resistant and 73% of those penicillin G-susceptible showed a minimum inhibitory concentration from 0.064 μg/mL to 0.25 μg/mL. Serogroup B was the most frequent (44.2%), followed by Z (16.3%), E (9.3%), and Y and W (2.3%), respectively. Multilocus sequence typing analysis identified 29 sequence types belonging to 12 clonal complexes. The sAniA protein was expressed in 8 out of 28 (29%) screened meningococcal carriage isolates.Conclusions: Serogroup B meningococcal carriage identified from oral and anal specimens among healthy MSM was the most frequent serogroup identified in this study. Molecular evaluation revealed a degree of similarity among strains belonging to the same clonal complex. [ABSTRACT FROM AUTHOR]

Abstract Background Several mutations have been described as responsible for rifampicin resistance in Neisseria meningitidis. However, the intriguing question on why these strains are so rare remains open. The aim of this study was to investigate the protein content and to identify differential expression in specific proteins in two rifampicin resistant and one susceptible meningococci using two-dimensional electrophoresis (2-DE) combined with mass spectrometry. Results In our experimental conditions, able to resolve soluble proteins with an isoelectric point between 4 and 7, twenty-three proteins have been found differentially expressed in the two resistant strains compared to the susceptible. Some of them, involved in the main metabolic pathways, showed an increased expression, mainly in the catabolism of pyruvate and in the tricarboxylic acid cycle. A decreased expression of proteins belonging to gene regulation and to those involved in the folding of polypeptides has also been observed. 2-DE analysis showed the presence of four proteins displaying a shift in their isoelectric point in both resistant strains, confirmed by the presence of amino acid changes in the sequence analysis, absent in the susceptible. Conclusions The analysis of differentially expressed proteins suggests that an intricate series of events occurs in N. meningitidis rifampicin resistant strains and the results here reported may be considered a starting point in understanding their decreased invasion capacity. In fact, they support the hypothesis that the presence of more than one protein differentially expressed, having a role in the metabolism of the meningococcus, influences its ability to infect and to spread in the population. Different reports have described and discussed how a drug resistant pathogen shows a high biological cost for survival and that may also explain why, for some pathogens, the rate of resistant organisms is relatively low considering the widespread use of a particular drug. This seems the case of rifampicin resistant meningococci.

Abstract Background To 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. Methods IMD 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. Results In 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. Conclusion Public 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.

We investigated the impact of social distancing measures, used to contain or mitigate SARS-CoV-2 spread, on the transmission of invasive meningococcal disease (IMD) in Italy. To this end, the temporal correlation between the implementation of lockdown measures in 2020 and IMD incidence was evaluated. A dramatic decline of IMD incidence was observed, suggesting that the measures applied to contain SARS-CoV-2 in Italy affected other infectious diseases transmitted through direct contact and droplets, at least in the early phase of the COVID-19 pandemic. [ABSTRACT FROM AUTHOR]

To the Editor: Invasive meningococcal disease is usually defined by the occurrence of meningitis or septicemia. Pericarditis might occur during the course of invasive infection. This clinical picture, defined as [...]

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, [...]

PorB is a pan-Neisserial major outer membrane protein with a trimeric β-barrel structure. Each monomer presents eight periplasmic turns and eight surface exposed loop regions with sequence variability. PorB induces activation of host cell responses via a TLR2-dependent mechanism likely mediated by electrostatic interactions between TLR2 and PorB surface exposed loops. Variability in the loop amino acid sequence is known to influence cell responses to PorB in vitro, particularly for the residues in L5 and L7. In this work, the sequence of the porB gene and the electrostatic surface charges of PorB from 35 invasive meningococcal isolates belonging to the main clonal complexes identified in Italy and from five carriage genomes available on the website were examined. Analysis of the porB encoding regions from the invasive meningococci has identified four new alleles and a potential association between porB alleles, serogroup, and clonal complexes. Through computer-based modeling and analysis of the electrostatic surface charges of PorB from these strains, loop charge segregation between PorB from invasive serogroups B and C was observed. Specifically, loops 1, 4, and 7 were negatively charged and L2 and L8 were mostly neutral in serogroup B isolates, while an overall homogeneous positive surface charge was present in PorB from invasive serogroup C strains. A higher PorB sequence variability was observed among carriage genomes, and a general prevalence of negative loop surface charges. The surface charge differences in PorB from serogroups B and C invasive and carriage strains may, in part, influence the outcomes of Neisseriae interactions with host cells. © 2016 IUBMB Life, 68(6):488-495, 2016 [ABSTRACT FROM AUTHOR]