Neisseria meningitidis serogroup X sequence type 767 in Turkey

Nasopharyngeal Meningococcal Carriage among Children and Adolescents in Turkey in 2018: An Unexpected High Serogroup X Carriage

Meningococcal carriage studies and transmission modeling can predict IMD epidemiology and used to define invasive meningococcal disease (IMD) control strategies. In this multicenter study, we aimed to evaluate the prevalence of nasopharyngeal Neisseria meningitidis (Nm) carriage, serogroup distribution, and related risk factors in Turkey. Nasopharyngeal samples were collected from a total of 1267 children and adolescents and were tested with rt-PCR. Nm carriage was detected in 96 participants (7.5%, 95% CI 6.1–9.0), with the peak age at 13 years (12.5%). Regarding age groups, Nm carriage rate was 7% in the 0–5 age group, was 6.9%in the 6–10 age group, was 7.9% in the 11–14 age group, and was 9.3% in the 15–18 age group. There was no statistically significant difference between the groups (p > 0.05). The serogroup distribution was as follows: 25% MenX, 9.4% MenA, 9.4% MenB, 2.1% MenC, 3.1% MenW, 2.1% for MenY, and 48.9% for non-groupable. The Nm carriage rate was higher in children with previous upper respiratory tract infections and with a high number of household members, whereas it was lower in children with antibiotic use in the last month (p < 0.05 for all). In this study, MenX is the predominant carriage strain. The geographical distribution of Nm strains varies, but serogroup distribution in the same country might change in a matter of years. Adequate surveillance and/or a proper carriage study is paramount for accurate/dynamic serogroup distribution and the impact of the proposed vaccination.

Neisseria meningitidis Serogroup X ST-5799 (ST-22 complex) in Turkey: A unique pediatric case

Although outbreaks of Neisseria meningitidis serogroup X occured in a couple of African countries, a limited number of serogroup X meningococcal cases were reported in America and Europe as well as Turkey. Additionally, serogroup X is still not represented in current conjugated meningococcal vaccines. Here, we describe the first pediatric case with meningitis caused by Neisseria meningitidis serogroup X ST-5799 (ST-22 complex) that formed a distinct lineage.

An efficient cell free enzyme-based total synthesis of a meningococcal vaccine candidate

Invasive meningococcal disease (IMD) is a global health problem and vaccination has proven the most effective way of disease control. Neisseria meningitidis serogroup X (NmX) is an emerging threat in the African sub-Saharan meningitis belt, but no vaccine is available today. Leading vaccines against Nm are glycoconjugates, in which capsular polysaccharides isolated from large-scale pathogen cultures are conjugated to adjuvant proteins. Though safe and efficacious even in infants, high costs and biohazard associated with the production limit abundant application of glycoconjugate vaccines particularly in the most afflicted nations. An existing NmX vaccine candidate (CPSXn-CRM₁₉₇) produced by established protocols from NmX capsule polysaccharide (CPSX) has been shown to elicit high bactericidal immunoglobulin G titres in mice. Here we describe the scalable in vitro synthesis of CPSXiv from chemically pure precursors by the use of recombinant NmX capsule polymerase. Application of the described coupling chemistry gives CPSXiv-CRM₁₉₇, which in mouse vaccination experiments behaves identical to the benchmark CPSXn-CRM₁₉₇. Excluding any biohazards, this novel process represents a paradigm shift in vaccine production and a premise towards vaccine manufacturing in emerging economies.

Review of invasive meningococcal disease during the last 40 years in Turkey

Due to the lack of comprehensive surveillance data representing Turkey, the authors aimed to derive information by panoramically reviewing all articles related to invasive meningococcal disease (IMD) published in the last 40 years. The following databases were reviewed: Ulakbim (the national database), BIOSIS Previews (from 1995), Evidence-Based Medicine Reviews-Cochrane Database of Systematic Reviews (from 2005), Embase (from 1996), Ovid MEDLINE(R) (from 1946) and Journals@Ovid Full Text (2014). Twenty-seven articles, 10 published in international journals and 17 in national journals, were identified. Only two were multicenter sentinel meningitis surveillance studies. Also, 74% of IMD patients were aged 5 years or younger and the median overall case fatality rate during childhood was 18.44%. Turkey is a country where meningococcal vaccination on a national basis is recommended by WHO. A vaccination strategy for serogroups B and W135 targeting the first 5 years, covering especially the first 12 months, would be appropriate.