Clonal spread of serogroup W135 meningococcal disease in Turkey

Multicenter Hospital-Based Prospective Surveillance Study of Bacterial Agents Causing Meningitis and Seroprevalence of Different Serogroups of Neisseria meningitidis, Haemophilus influenzae Type b, and Streptococcus pneumoniae during 2015 to 2018 in Turkey

Acute bacterial meningitis (ABM) is one of the most common life-threatening infections in children. The incidence and prevalence of ABM vary both geographically and temporally; therefore, surveillance systems are necessary to determine the accurate burden of ABM. The Turkish Meningitis Surveillance Group has been performing a hospital-based meningitis surveillance study since 2005 across several regions in Turkey. Meningococcus was the major ABM-causing agent during the 2015-to-2018 period, during which MenB was the dominant serogroup.

The etiology of bacterial meningitis in Turkey changed after the implementation of conjugated vaccines against Streptococcus pneumoniae and Haemophilus influenzae type b (Hib) in the Turkish National Immunization Program (NIP). Administration of Hib vaccine and PCV-7 (7-valent pneumococcal conjugate vaccine) was implemented in NIP in 2006 and 2009, respectively. In 2011, PCV-7 was replaced with PCV-13. Meningococcal vaccines have not yet been included in Turkish NIP. This prospective study comprised 27 hospitals located in seven regions of Turkey and represented 45% of the population. Children aged between 1 month and 18 years who were hospitalized with suspected meningitis were included. Cerebrospinal fluid (CSF) samples were collected, and bacterial identification was made according to the multiplex PCR assay results. During the study period, 994 children were hospitalized for suspected meningitis, and Hib (n = 3, 2.4%), S. pneumoniae (n = 33, 26.4%), and Neisseria meningitidis (n = 89, 71%) were detected in 125 samples. The most common meningococcal serogroup was MenB. Serogroup W comprised 13.9% (n = 5) and 7.5% (n = 4) of the meningococci in 2015 to 2016 and 2017 to 2018, respectively. Serogroup C was not detected. There were four deaths in the study; one was a pneumococcus case, and the others were serogroup B meningococcus cases. The epidemiology of meningococcal diseases has varied over time in Turkey. Differing from the previous surveillance periods, MenB was the most common serogroup in the 2015-to-2018 period. Meningococcal epidemiology is so dynamic that, for vaccination policies, close monitoring is crucial.

IMPORTANCE Acute bacterial meningitis (ABM) is one of the most common life-threatening infections in children. The incidence and prevalence of ABM vary both geographically and temporally; therefore, surveillance systems are necessary to determine the accurate burden of ABM. The Turkish Meningitis Surveillance Group has been performing a hospital-based meningitis surveillance study since 2005 across several regions in Turkey. Meningococcus was the major ABM-causing agent during the 2015-to-2018 period, during which MenB was the dominant serogroup.

Surveillance of penicillin resistance of Neisseria meningitidis strains from invasive infections between 2013 and 2018 in Turkey

Neisseria meningitidis (N. meningitidis) is regarded as the leading cause of bacterial meningitis in many regions of the world. The empiric antimicrobial treatment is mainly based on antimicrobial resistance and patient characteristics. We aimed to analyze susceptibility patterns of N. meningitidis strains isolated in Turkey. Invasive meningococci collected in a multicenter, hospital-based, epidemiological surveillance study of pediatric (0-18 years of age) bacterial meningitis cases between 2013 and 2018 were studied. Five isolates (8.7%) displayed resistance to penicillin-G, while 13 isolates (22.8%) had intermediate susceptibility. All isolates were cefotaxime and rifampin susceptible. The data shows appropriateness of third-generation cephalosporins in empirical use for meningococcal infections in children. Since Turkey is located in a transition zone geographically, surveillance reports are very crucial.

Recent changes in the epidemiology of Neisseria meningitidis serogroup W across the world, current vaccination policy choices and possible future strategies

Invasive meningococcal disease (IMD) is a serious disease that is fatal in 5–15% and disabling in 12–20% of cases. The dynamic and unpredictable epidemiology is a particular challenge of IMD prevention. Although vaccination against meningococcal serogroups A (MenA), MenC and, more recently, MenB, are proving successful, other serogroups are emerging as major IMD causes. Recently, surges in MenW incidence occurred in South America, Europe, Australia and parts of sub-Saharan Africa, with hypervirulent strains being associated with severe IMD and higher fatality rates. This review describes global trends in MenW-IMD epidemiology over the last 5–10 years, with emphasis on the response of national/regional health authorities to increased MenW prevalence in impacted areas. Several countries (Argentina, Australia, Chile, the Netherlands and UK) have implemented reactive vaccination campaigns to reduce MenW-IMD, using MenACWY conjugate vaccines. Future vaccination programs should consider the evolving epidemiology of MenW-IMD and the most impacted age groups.

Prevalence and antibiotic resistance profiles of cerebrospinal fluid pathogens in children with acute bacterial meningitis in Yunnan province, China, 2012-2015

Acute bacterial meningitis is still considered one of the most dangerous infectious diseases in children. To investigate the prevalence and antibiotic resistance profiles of cerebrospinal fluid (CSF) pathogens in children with acute bacterial meningitis in Southwest China, CSF samples from 179 meningitis patients (3 days to 12 years old) with positive culture results were collected from 2012 to 2015. Isolated pathogens were identified using the Vitek-32 system. Gram stain results were used to guide subcultures and susceptibility testing. The antimicrobial susceptibility of isolates was determined using the disc diffusion method. Of the isolates, 50.8% were Gram-positive bacteria, and 49.2% were Gram-negative bacteria. The most prevalent pathogens were E. coli (28.5%), Streptococcus pneumoniae (17.8%), Staphylococcus epidermidis (10.0%), Haemophilus influenzae type b (9.5%), and group B streptococcus (7.2%). In young infants aged ≤3 months, E. coli was the organism most frequently isolated from CSF (39/76; 51.3%), followed by group B streptococcus (13/76; 17.1%) and Streptococcus pneumoniae (8/76; 10.5%). However, in young infants aged >3 months, the most frequently isolated organism was Streptococcus pneumoniae (24/103; 23.3%), followed by Staphylococcus epidermidis (18/103; 17.5%) and Haemophilus influenzae type b (16/103; 15.5%). Antimicrobial susceptibility tests indicated that for E. coli isolates, the susceptibility rates to aminoglycosides ranged from 56.8% to 100.0%, among them, amikacin was identified as the most effective against E. coli. As for cephalosporins, the susceptibility rates ranged from 29.4% to 78.4%, and cefoxitin was identified as the most effective cephalosporin. In addition, the susceptibility rates of piperacillin/tazobactam and imipenem against E. coli were 86.3% and 100%. Meanwhile, the susceptibility rates of Streptococcus pneumoniae isolates to penicillin G, erythromycin, chloramphenicol, ceftriaxone and tetracycline were 68.8%, 0.0%, 87.5%, 81.3% and 0.0%, respectively. Gentamycin, ofloxacin, linezolid and vancomycin were identified as the most effective antibiotics for Streptococcus pneumoniae, each with susceptibility rates of 100%. It was notable that other emerging pathogens, such as Listeria monocytogenes and group D streptococcus, cannot be underestimated in meningitis.

Bacterial agents causing meningitis during 2013-2014 in Turkey: A multi-center hospital-based prospective surveillance study

This is an observational epidemiological study to describe causes of bacterial meningitis among persons between 1 month and 18 y of age who are hospitalized with suspected bacterial meningitis in 7 Turkish regions. covering 32% of the entire population of Turkey. We present here the results from 2013 and 2014. A clinical case with meningitis was defined according to followings: any sign of meningitis including fever, vomiting, headache, and meningeal irritation in children above one year of age and fever without any documented source, impaired consciousness, prostration and seizures in those < 1 y of age. Single tube multiplex PCR assay was performed for the simultaneous identification of bacterial agents. The specific gene targets were ctrA, bex, and ply for N. meningitidis, Hib, and S. pneumoniae, respectively. PCR positive samples were recorded as laboratory-confirmed acute bacterial meningitis. A total of 665 children were hospitalized for suspected acute meningitis. The annual incidences of acute laboratory-confirmed bacterial meningitis were 0.3 cases / 100,000 population in 2013 and 0.9 cases/100,000 in 2014. Of the 94 diagnosed cases of bacterial meningitis by PCR, 85 (90.4%) were meningococcal and 9 (9.6%) were pneumococcal. Hib was not detected in any of the patients. Among meningococcal meningitis, cases of serogroup Y, A, B and W-135 were 2.4% (n = 2), 3.5% (n = 3), 32.9% (n = 28), and 42.4% (n = 36). No serogroup C was detected among meningococcal cases. Successful vaccination policies for protection from bacterial meningitis are dependent on accurate determination of the etiology of bacterial meningitis. Additionally, the epidemiology of meningococcal disease is dynamic and close monitoring of serogroup distribution is comprehensively needed to assess the benefit of adding meningococcal vaccines to the routine immunization program.

Genomic resolution of an aggressive, widespread, diverse and expanding meningococcal serogroup B, C and W lineage

OBJECTIVES

Neisseria meningitidis is a leading cause of meningitis and septicaemia. The hyperinvasive ST-11 clonal complex (cc11) caused serogroup C (MenC) outbreaks in the US military in the 1960s and UK universities in the 1990s, a global Hajj-associated serogroup W (MenW) outbreak in 2000-2001, and subsequent MenW epidemics in sub-Saharan Africa. More recently, endemic MenW disease has expanded in South Africa, South America and the UK, and MenC cases have been reported among European and North American men who have sex with men (MSM). Routine typing schemes poorly resolve cc11 so we established the population structure at genomic resolution.

METHODS

Representatives of these episodes and other geo-temporally diverse cc11 meningococci (n = 750) were compared across 1546 core genes and visualised on phylogenetic networks.

RESULTS

MenW isolates were confined to a distal portion of one of two main lineages with MenB and MenC isolates interspersed elsewhere. An expanding South American/UK MenW strain was distinct from the 'Hajj outbreak' strain and a closely related endemic South African strain. Recent MenC isolates from MSM in France and the UK were closely related but distinct.

CONCLUSIONS

High resolution 'genomic' multilocus sequence typing is necessary to resolve and monitor the spread of diverse cc11 lineages globally.

Meningitis caused by Neisseria Meningitidis, Hemophilus Influenzae Type B and Streptococcus Pneumoniae during 2005-2012 in Turkey. A multicenter prospective surveillance study

Successful vaccination policies for protection from bacterial meningitis are dependent on determination of the etiology of bacterial meningitis. Cerebrospinal fluid (CSF) samples were obtained prospectively from children from 1 month to ≤18 years of age hospitalized with suspected meningitis, in order to determine the etiology of meningitis in Turkey. DNA evidence of Neisseria meningitidis (N. meningitidis), Streptococcus pneumoniae (S. pneumoniae), and Hemophilus influenzae type b (Hib) was detected using multiplex polymerase chain reaction (PCR). In total, 1452 CSF samples were evaluated and bacterial etiology was determined in 645 (44.4%) cases between 2005 and 2012; N. meningitidis was detected in 333 (51.6%), S. pneumoniae in 195 (30.2%), and Hib in 117 (18.1%) of the PCR positive samples. Of the 333 N. meningitidis positive samples 127 (38.1%) were identified as serogroup W-135, 87 (26.1%) serogroup B, 28 (8.4%) serogroup A and 3 (0.9%) serogroup Y; 88 (26.4%) were non-groupable. As vaccines against the most frequent bacterial isolates in this study are available and licensed, these results highlight the need for broad based protection against meningococcal disease in Turkey.

Genetic diversity of Neisseria meningitidis serogroup C ST-4821 in China based on multiple-locus variable number tandem repeat analysis

Neisseria meningitidis sequence type (ST)-4821 was first reported in China in 2003, and a new hyper-virulent lineage has been designated as the ST-4821 complex. A large number of N. meningitidis ST-4821 strains have been identified in China since 2003; however, the microevolution characteristics of this complex are unclear. Different combinations of variable number of tandem repeats (VNTR) loci were used in multiple-locus VNTR analysis (MLVA) to analyze 118 N. meningitidis serogroup C ST-4821 strains isolated from seventeen provinces between 2003 and 2012. Additionally, MLVA with five VNTR loci was performed due to its high discriminatory power. One hundred and eighteen isolates were found to comprise 112 subtypes based on MLVA, and 16 outbreak-associated strains were clustered into one group. These data indicate a high level of diversity for N. meningitidis ST-4821 due to microevolution in the last decade. In addition, the results revealed high similarity between isolates from the same geographic origins, which is helpful when monitoring the spread of N. meningitidis serogroup C ST-4821 and will provide valuable information for the control and prevention of bacterial meningitis in China.

Spread of Neisseria meningitidis serogroup W clone, China

During February 2011–June 2012, invasive infection with Neisseria meningitidis serogroup W was identified in 11 persons in southeastern China. All isolates tested had matching or near-matching pulsed-field gel electrophoresis patterns and belonged to multilocus sequence type 11. The epidemiologic investigation suggested recent transmission of this clonal complex in southeastern China.

Characterization of Neisseria meningitidis isolates from Egypt using multilocus sequence typing

To characterize Neisseria meningitidis isolates collected from cerebrospinal fluid of meningitis cases in Egypt (1998-2003) as part of surveillance studies, 67 isolates were serogrouped, tested for antibiotic sensitivity and analyzed using multilocus sequence typing (MLST). Results show that isolates expressing serogroup B (50.7%) and serogroup A (34.3%) antigens were predominant in Egypt during the surveillance period, possibly due to suppression of other serogroups by meningococcal vaccines in current use. Intermediate resistance to penicillin was observed in 71% of the isolates, suggesting a need for physicians to shift to third-generation cephalosporins during the empirical treatment of infection. Recurrent lineages of N. meningitidis in Egypt appear to originate from Europe and other Middle Eastern countries. Of 19 sequence types detected, five were unique to Africa and 10 were not observed previously in the MLST database. The information obtained illustrates the changing dynamics of meningitis after vaccine introduction in Egypt.

Distribution of serogroups and sequence types in disease-associated and carrier strains of Neisseria meningitidis isolated in China between 2003 and 2008

Given the unpredictability of Neisseria meningitidis outbreaks and the increased prevalence of serogroup C strains following the introduction of serogroup A-based vaccines, we conducted an analysis of serogroups and sequence types (STs) in disease-associated and carrier N. meningitidis isolates that have emerged in China since 2003. We used multilocus sequence-typing techniques to investigate 371 N. meningitidis strains isolated from patients with meningitis and healthy carriers. Two lineages were identified in serogroup A and C isolates, genotyped as the ST5 complex and ST4821 complex, respectively. Both clonal complexes were found throughout China, although ST4821 was more concentrated in the eastern region of the country. The ST5 complex has been persistent in China since the late 1980s and has since spread across the entire country. Isolates belonging to the ST4821 complex have been a dominant lineage since 2003.

Critical appraisal of a quadrivalent CRM(197) conjugate vaccine against meningococcal serogroups A, C W-135 and Y (Menveo) in the context of treatment and prevention of invasive disease

Worldwide, invasive meningococcal disease affects about 500,000 people annually. Case fatality in developed countries averages 10%, and higher rates are reported in less prosperous regions. According to the World Health Organization, the most important pathogenic serogroups are A, B, C, W-135, X, and Y. Clinical features of invasive meningococcal disease make diagnosis and management difficult. Antibiotic measures are recommended for prophylaxis after exposure and for treatment of invasive meningococcal disease cases; however, resistant strains may be emerging. Vaccines are generally regarded as the best preventative measure for invasive meningococcal disease. Polysaccharide vaccines against serogroups A, C, W-135, and Y using protein conjugation technology have clear advantages over older plain polysaccharide formulations without a protein component. The first quadrivalent meningococcal conjugate vaccine (MenACWY-D) was licensed in the US in 2005. More recently, MenACWY-CRM (Menveo^®) was licensed in Europe, the US, the Middle East, and Latin America. MenACWY-CRM uses cross-reactive material 197, a nontoxic mutant of diphtheria toxin, as the carrier protein. MenACWY-CRM offers robust immunogenicity in all age groups, with a tolerability profile similar to that of a plain polysaccharide vaccine. Given its potential for protecting persons from infancy to old age, MenACWY-CRM offers the opportunity to protect broad populations against invasive meningococcal disease. The most optimal strategy for use of the vaccine has to be assessed country by country on the basis of local epidemiology, individual health care systems, and need.

Structural basis for solute transport, nucleotide regulation, and immunological recognition of Neisseria meningitidis PorB

PorB is the second most prevalent outer membrane protein in Neisseria meningitidis. PorB is required for neisserial pathogenesis and can elicit a Toll-like receptor mediated host immune response. Here, the x-ray crystal structure of PorB has been determined to 2.3 A resolution. Structural analysis and cocrystallization studies identify three putative solute translocation pathways through the channel pore: One pathway transports anions nonselectively, one transports cations nonselectively, and one facilitates the specific uptake of sugars. During infection, PorB likely binds host mitochondrial ATP, and cocrystallization with the ATP analog AMP-PNP suggests that binding of nucleotides regulates these translocation pathways both by partial occlusion of the pore and by restricting the motion of a putative voltage gating loop. PorB is located on the surface of N. meningitidis and can be recognized by receptors of the host innate immune system. Features of PorB suggest that Toll-like receptor mediated recognition outer membrane proteins may be initiated with a nonspecific electrostatic attraction.

Expression, purification and preliminary X-ray analysis of the Neisseria meningitidis outer membrane protein PorB

The Neisseria meningitidis outer membrane protein PorB was expressed in Escherichia coli and purified from inclusion bodies by denaturation in urea followed by refolding in buffered LDAO on a size-exclusion column. PorB has been crystallized in three different crystal forms: C222, R32 and P6(3). The C222 crystal form may contain either one or two PorB monomers in the asymmetric unit, while both the R32 and P6(3) crystal forms contained one PorB monomer in the asymmetric unit. Of the three, the P6(3) crystal form had the best diffraction quality, yielding data extending to 2.3 A resolution.

A prospective study of etiology of childhood acute bacterial meningitis, Turkey

Vaccines to prevent bacterial meningitis in this region must provide reliable protection against serogroup W-135.

Determination of the etiology of bacterial meningitis and estimating cost of disease are important in guiding vaccination policies. To determine the incidence and etiology of meningitis in Turkey, cerebrospinal fluid (CSF) samples were obtained prospectively from children (1 month–17 years of age) with a clinical diagnosis of acute bacterial meningitis. Multiplex PCR was used to detect DNA evidence of Streptococcus pneumoniae, Haemophilus influenzae type b (Hib), and Neisseria meningitidis. In total, 408 CSF samples were collected, and bacterial etiology was determined in 243 cases; N. meningitidis was detected in 56.5%, S. pneumoniae in 22.5%, and Hib in 20.5% of the PCR-positive samples. Among N. meningitidis–positive CSF samples, 42.7%, 31.1%, 2.2%, and 0.7% belonged to serogroups W-135, B, Y, and A, respectively. This study highlights the emergence of serogroup W-135 disease in Turkey and concludes that vaccines to prevent meningococcal disease in this region must provide reliable protection against this serogroup.

Age-specific seroprevalence of serogroup C meningococcal serum bactericidal antibody activity and serogroup A, C, W135 and Y-specific IgG concentrations in the Turkish population during 2005

Like many other developing countries; there is no accurate information about the antibody levels against Neisseria meningitidis in Turkey. We collected serum samples from four health centers located in different geographic regions and stratified according to age in order to obtain a baseline seroprevalence of protective antibodies to meningococcal serogroup C and provide data on seroprevalence of IgG antibodies to serogroups A, C, W135 and Y. Sera were tested for serum bactericidal antibodies (SBA) to serogroup C meningococci using rabbit serum as the complement source and by a bead based assay for serogroup A, C, W135 and Y-specific IgG. It was observed that 30% and 12% of individuals within the study population had SBA titers of > or =8 and > or =128, respectively. Overall; at least 70% of the population are susceptible (SBA titer <8) to meningococcal serogroup C disease. The rate of susceptibility was highest in infants aged 7-12 months and young children (1-4 years). Regardless of age, for serogroup A, C, W135 and Y, 60.5%, 27.2%, 12.3% and 19.2% of subjects, respectively, had serogroup-specific IgG concentrations > or =2 microg/mL. These data highlight that a large proportion of the Turkish population are susceptible to serogroups C, W135 and Y and should be considered, along with serogroup-specific disease incidence data, in future decisions on possible meningococcal vaccination programmes.