Serogroup W135 Research Articles

Meningococcal meningitis in Chile between 1990 and 2019

To summarize the available evidence on the epidemiological profile of acute bacterial meningitis due to Neisseria meningitidis in Chile, analyzing the incidence between 1990 and 2019. A systematized review of primary articles was carried out following the Cochrane Collaboration standards. The information sources were PubMed, Scielo, and LILACS. Publications on acute bacterial meningitis due to Neisseria meningitidis were included, with a descriptive design, and in English and Spanish. Studies on the effectiveness of vaccines and diagnostic techniques were excluded. Between 1990 and 2019, the evidence collected focuses exclusively on the year 2012. Of the 133 cases of invasive meningococcal disease (IMD) reported that year, 42 cases presented with meningitis. Of the IMD cases caused by serogroup W135 strains, 21.7% of the cases presented with meningitis (13 cases), compared with the "Non-W135" strains, in which it was 67.4% (29 cases). Lethality due to IMD was higher in patients affected by serogroup W135 (26.7%), compared with patients affected by serogroup "Non-W135" (13.9%). The year 2012 shows a change in the prevalent serogroup from serogroup B to W, with a decrease in cases of meningitis and an increase in cases of meningo- coccemia and the lethality of IMD.

Humoral and cellular immune responses induced by serogroup W135 meningococcal conjugate and polysaccharide vaccines

Investigating the mechanisms by which W135 meningococcal conjugate (PSW135-TT) activates adaptive immune responses in mice can provide a comprehensive understanding of the immune mechanisms of bacterial polysaccharide conjugate vaccines. We compared B-cell and T-cell immune responses immunized with W135 meningococcal capsular polysaccharides (PSW135), tetanus toxoid (TT) and PSW135-TT in mice. The results showed that PSW135-TT could induce higher PSW135-specific and TT-specific IgG antibodies with a significant enhancement after two doses. All serum antibodies immunized with PSW135- TT had strong bactericidal activity, whereas none of the serum antibodies immunized with PSW135 had bactericidal activity. Besides, IgM and IgG antibodies immunized with PSW135-TT after two doses were positively correlated with the titer of bactericidal antibodies. We also found Th cells favored Th2 humoral immune responses in PSW135-TT, PSW135, and TT-immunized mice, especially peripheral blood lymphocytes. Furthermore, PSW135-TT and TT could effectively activate bone marrow derived dendritic cells (BMDCs) and promote BMDCs to highly express major histocompatibility complex Ⅱ (MHCⅡ), CD86 and CD40 molecules in mice, whereas PSW135 couldn’t. These data verified the typical characteristics of PSW135-TT and TT as T cell dependent antigen (TD-Ag) and PSW135 as T cell independent antigen (TI-Ag), which will be very helpful for further exploration of the immune mechanism of polysaccharide-protein conjugate vaccines and improvement of the quality of bacterial polysaccharide conjugate vaccines in future.

Investigation on the carriage prevalence of Neisseria meningitidis in healthy population in Jiangsu Province in 2019 and 2020

In order to investigate carriage status and serum groups distribution of Neisseria meningitidis(Nm) among healthy population in Jiangsu Province, four counties were selected as monitoring sites by random sampling method for cross-sectional study. Throat swab specimens were collected from four monitoring sites in October to November 2019 and November to December 2020 for bacterial culture and Real-time PCR detection. Chi-square test was used to compare the positive rate of Neisseria meningitidis, and multiple logistic regression model was used to analyze the influencing factors of Neisseria meningitidis carrier rate. The results showed that among 1 512 samples, 57 strains of Nm were isolated, and the carrier rate was 3.77%. Serogroup B was the dominant group (36.84%), followed by un-known serogroups (33.33%), serogroup C was the third (17.54%), serogroup W135 and serogroup A were 7.02% and 5.26%, respectively. The carriage rate (8.60%) of 15-20 years old was significantly higher than others (1.77%-3.74%)(Pearson χ2=18.211, P<0.05). Region, age and immunization history were risk factors for Neisseria meningitidis carrier rate. In summary, the Nm carrier rate of healthy population in Jiangsu Province is relatively low, which indicates that the epidemic cases will continue to be sporadic in the future. However, the prevention and control of meningococcal epidemics on campus should be strengthened, and the monitoring of neisseria meningitidis group B should be maintained as it has become the dominant epidemic strain.

Meningococcal pneumonia, a case report

Background: Traditionally, Neisseria meningitidis posed significant morbidity and mortality causing epidemics or sporadic cases of meningitis or septicemia with moribund complications if untreated early. However, it has been observed rarely causing community-acquired pneumonia, without any central nervous system complications. Case Description: A 64 year old gentleman, with underlying diabetes mellitus presented with 1 week history of non-productive cough, fever and lethargy. There was no neck stiffness or headache and the immediate family members denied any altered sensorium or behavioral changes. He was well prior to admission and no recent travelling or Hajj pilgrimage. He was febrile at 38.3 C and fine bibasal crepitations noted on auscultation. Chest radiograph revealed bilateral perihilar haziness. Blood culture grew Neisseria meningitidis, identified by Vitek-2 NH and API NH systems. The antimicrobial susceptibility test showed that the isolate was susceptible to ceftriaxone, meropenem. Penicillin was intermediate with MIC of 0.094 μg/ml. The isolate was also sent to Institute of Medical Research (IMR), Kuala Lumpur which has confirmed the isolate as Neisseria meningitidis serogroup W135. The patient was treated with IV ceftriaxone for 1 week and kept in isolation room with contact precaution advised. Close contacts and laboratory personnel were offered post-exposure prophylaxis for those who had been exposed. He was subsequently discharged well. Discussion: Neisseria meningitidis is frequently associated with meningitis and meningococcal disease with severe debilitating complications. It is a fastidious gram negative diplococci, which is found in humans, as the only reservoir. It is transmissible by droplets from the nasopharynx of colonized persons. This organism commonly causes meningococcemia and acute meningitis. However, meningococcal pneumonia was being infrequently reported, partly due to low clinical suspicion and uncertainty to establish diagnosis of pneumonia. Many cases were initially misidentified hence the need for high clinical suspicion and precise laboratory identifications in suspected cases. Conclusion: Here, we reported a case of primary meningococcal pneumonia. The patient did not succumb to any neurological complications and was discharged well after one week of ceftriaxone. Thus, Neisseria meningitidis should be considered as an aetiological agent of community-accquired pneumonia especially in the elderly.

Epidemiology and antibiotic resistance profile of bacterial meningitis in Morocco from 2015 to 2018.

Over a 4-year study period from 2015 to 2018, altogether 183 isolates of bacterial meningitis were collected from 12 hospitals covering the entire Moroccan territory. Neisseria meningitidis represented 58.5%, Streptococcus pneumoniae 35.5%, and Haemophilus influenzae type b 6%. H. influenzae type b mainly affected 5-year-olds and unvaccinated adults. N. meningitidis serogroup B represented 90.7% followed by serogroup W135 with 6.5%. Decreased susceptibility to penicillin G (DSPG) for all isolates accounted for 15.7%, with 11.6% being resistant to penicillin G (PG) and 4.1% decreased susceptibility. Cumulative results of all strains showed 2.7% decreased susceptibility to amoxicillin and 3.3% resistant, 2.2% of isolates were resistant to third-generation cephalosporin and 2.2% were decreased susceptible, 5.5% were resistant to chloramphenicol and 2.7% were resistant to rifampin. The frequency of DSPG observed in our study is more common in S. pneumoniae than in N. meningitidis (P < 0.05). These isolates have been found to be highly susceptible to antibiotics used for treatment and prophylaxis chemotherapy and the observed resistance remains rare. The impact of introduction of conjugate vaccines against H. influenzae type b and S. pneumoniae (PCVs) is an advantage in reducing meningitis cases due to these two species.

Artritis por meningococo. Revisión de un caso

N. Meningitidis serogroup (A, B, C), are main causers of disease. Serogroup W-135 incidence is lower nowadays and, although it is increasing, is such an uncommon infection in adults. We report a case of a monoarthritis knee due to Neisseria meningitidis (W- 135) in an inmunocompetent 50 year- old male.

Outbreaks of meningococcal meningitis in non-African countries over the last 50 years: a systematic review.

BackgroundMeningococcal disease is caused by the bacteria Neisseria meningitidis, leading to substantial mortality and severe morbidity; with serogroups A, B, C, W135, X and Y most significant in causing disease. An outbreak is defined as multiple cases of the same serogroup occurring in a population over a short time-period. A systematic review was performed to gain insight into outbreaks of meningococcal disease and to describe the temporal pattern over the last 50 years in non-African countries.MethodsPubMed and EMBASE were searched for English-language publications on outbreaks of meningococcal disease in non-African countries between January 1966 and July 2017, with an additional grey literature search. Articles and reports were considered eligible if they reported confirmed meningococcal outbreak cases, included the region, number of cases, and the start and end dates of the outbreak. Data on outbreaks was stratified by geographical region in accordance with the World Health Organization (WHO) regional classification, and case-fatality rates (CFRs) were calculated.ResultsOf the identified publications, 3067 were screened and 73 included, reporting data from 83 outbreaks. The majority of outbreaks were identified in the regions of the Americas (41/83 outbreaks), followed by the European region (30/83 outbreaks). In each of the Western Pacific, Eastern Mediterranean, and South-East Asian regions there were <10 outbreaks reported. The predominant serogroup in the majority of outbreaks was serogroup C (61%), followed by serogroup B (29%), serogroup A (5%) and serogroup W135 (4%). Outbreaks showed a peak in the colder months of both the Northern and Southern Hemispheres. Of the 54 outbreaks where CFR was calculable for all outbreak cases, it ranged from 0%-80%.ConclusionsThese data present a retrospective view of the patterns for meningococcal disease outbreaks in non-African countries, and provide valuable data for monitoring future changes in disease epidemiology and informing preventive measures.

Analysis of current epidemiological and clinical characteristics for laboratory confirmed epidemic cerebrospinal meningitis cases in Shandong Province, 2007-2016

Objective: To analyze epidemiological and clinical characteristics of laboratory confirmed epidemic cerebrospinal meningitis cases. Methods: Epidemiological and clinical informations and cerebrospinal fluid (CSF) and blood specimens of AMES (acute meningitis/encephalitis syndrome) cases were collected in the six sentinel hospitals from 2007 to 2016. neisseria meningitides (Nm) species and serogroup identification were detected by the methods of real-time fluorescent quantitative polymerase chain reaction (Real-time PCR) and bacterial culture, and epidemiological and clinical characteristics of laboratory confirmed epidemic cerebrospinal meningitis cases were analyzed. Results: 6 809 AMES cases were reported from 2007 to 2016. Total 4 422 cases were detected, and 90 cases were Nm positive. Through the methods of Real-time PCR, bacterial blood culture and CSF culture, the numbers of Nm positive cases were 90, 2 and 1 respectively. Twenty-two Nm cases were identified from 2007 to 2011 (4 cases were ungrouped), which with the highest incidence in serogroup C cases (17/18), and one cases was ungroupable Nm. Nm laboratory confirmed cases (68 cases) were increased dramatically and mainly occurred in serogroup B cases (43/67, 64.2%) from 2012 to 2016, with serogroup C cases highly decreased (5/67, 7.5%) and ungroupable Nm cases increased (13/67, 19.4%) meanwhile. Serogroup W135 and X cases were first detected at 2012 and 2014, and serogroup A remaining a low level which only detected one case at 2013. The morbidity of epidemic cerebrospinal meningitis was occured in the whole year, and mainly in winter and spring. The ratio of Nm laboratory confirmed cases to AMES cases during November to May (3.5%, 67/1 920) was higher than that during June to October (0.9%, 23/2 502) (χ(2)=34.45, P<0.001). Most Nm cases were children, students and farmers, and account for 30.0% (27/90), 31.1% (28/90), 18.9% (17/90), respectively. The majority of Nm cases were under 20 years old (60/90, 66.67%), and serogroup C cases (17/22, 77.3%) mainly occurred in over 12 years old population, while serogroup B (24/43, 55.8%) and ungroupable (6/14) cases mainly occurred in under 12 years old population. The main clinical symptoms of epidemic cerebrospinal meningitis cases were fever (78/90, 86.7%), headache (59/90, 65.6%) and vomiting (51/90, 56.7%). Misdiagnosis rate of admitting diagnosis was up to 87.8% (79/90) for the reason of atypical features in specific symptoms and blood or CSF positive index. The well-healed ratio in correct diagnosed group (7/11) was higher than that in misdiagnosed group (2.5%, 2/79) (χ(2)=40.61, P<0.001). Conclusion: The clinical symptoms of epidemic cerebrospinal meningitis cases were atypical, and the diagnosed sensitivity and accuracy would be improved by enhanced molecular biology detection. The predominant epidemic serogroup of Nm switched from serogroup C to B, and the key work was surveaylance of serogroup transition.

Antibiotic Susceptibility Patterns of &amp;lt;i&amp;gt;Neisseria Meningitides&amp;lt;/i&amp;gt; Isolates from Asymptomatic Carriers in Gurage Zone, Southern Ethiopia

Neisseria meningitides represents a pathogen of great public health importance in both developed and developing countries. Resistance to some antimicrobial agents used either for therapy of invasive infections or for prophylaxis of case contacts has long been recognized. However, there is no data in relation with the circulating serotypes and antimicrobial resistance patterns of Neisseria meningitides in Ethiopia. Therefore; the aim of this study was to assess drug susceptibility patterns of Neisseria meningitides from asymptomatic carrier for all age group at Meskan and Mareko Districts, Gurage Zone, in the Southern Nations, Nationalities and Peoples Regional State Ethiopia. A Cross-sectional survey of an age-stratified population in Meskan and Mareko Districts, Gurage Zone, in the Southern Nations, Nationalities and Peoples Regional State in Ethiopia was conducted at AHRI as part of the MenAfricar project. A total of 4110 subjects were screened and from these 187 Neisseria meningitides positive isolates was selected for Antimicrobial susceptibility testing (AST). Antimicrobial susceptibility test was done on stored Neisseria meningitides isolates. The activities of ten antimicrobial agents used for treatment and prophylaxis of meningococcal disease were investigated. The AST was performed for Neisseria meningitides isolates according to the criteria of the CLSI guide line by disk diffusion method. Data were analysed by using SPSS version 20.0 software. From 187 isolates 8(4.28%) were serogroup X, 24(12.83%) were serogroup Y, 1(0.53%) were serogroup W135, and 154(82.35%) were non determinant (ND). Cotrimoxazol resistant were the highest accounting116(62%), Ciprofloxacine resistant were 112(60%), Cefotaxime resistant were 26(14%), Ceftriaxone resistant were 24(13%), Meropenenem resistantwere 21(11%), Minocycline resistant were 15(8%), Rifampine resistant were 149(7%), 10(5%) were resistant to Azithromycine, 7(4%) were resistant to Chloramphenicol and 6(3%) were resistant to Levofloxacin and 102(54.5%) isolates were resistance for more than one drug. So, it has beenconcluded that an antimicrobial susceptibility pattern of Neisseria meningitides among asymptomatic carriers is high and continued surveillance of meningococci for antimicrobial resistance is necessary to monitor early detection of changes in susceptibility patterns that might affect recommendations for chemoprophylaxis and treatment.

Optimization of real-time multiplex polymerase chain reaction for the diagnosis of acute bacterial meningitis and Neisseria meningitidis serogrouping

Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae type B are responsible for about 80-85% of acute bacterial meningitis cases among adults and in our country it is mandatory to report bacterial meningitis cases caused by these agents. In recent years, disease control programs have focused especially on these three pathogens in our country. It is very important to know the causative agent of meningitis for prevention/control measures, choice of treatment regimen, and prediction of the severity and the course of the disease. Rapid diagnosis of meningococcal meningitis is especially vital. In addition, the identification of N.meningitidis serogroups in the community is also important for the decision of the type and combination of vaccine to be administered. The aim of this study was to optimize the real-time multiplex polymerase chain reaction (Rt-multiplex PCR) for the diagnosis of the disease and serogrouping of N.meningitidis in clinical samples in a direct, quick and reliable way. In this study, three Rt-multiplex PCR assays were optimized and standardized for the detection of N.meningitidis, H.influenzae and S.pneumoniae (NHS mix) and for the serogrouping of N.meningitidis (BCY mix and AWX mix) in our laboratory. Sensitivity of the Rt-multiplex PCR method was detected by reference strains and simulation studies. Forty three samples (41 cerebrospinal fluid (CSF), 1 serum and 1 clinical isolate) with the suspicion of acute bacterial meningitis and six nasopharyngeal isolates sent to National Reference Laboratory for Molecular Microbiology between July 2012-May 2014 were included in the present study. All samples were examined with the Rt-multiplex PCR methods. Clinical isolates were studied by both conventional and Rt-multiplex PCR methods. Oxidase, catalase test, Gram stain, API-NH and agglutination tests with specific antisera were performed in the National Respiratory Pathogens Reference Laboratory. The detection limit of the method, which was optimized and standardized in our laboratory was determined as 102 cfu/ml. The CT (threshold cycle) value in this dilution was detected approximately as 35. N.meningitidis was detected in 14 of the 41 CSF samples by the NHS mix. However, only 10 of the positive samples could be typed with BCY mix and AWX mix. Eight (80%) of them were serogroup B, one of each was (10%) serogroup A and serogroup W135, respectively. All the isolates (six nasopharyngeal and one clinical specimen) were identified as N.meningitidis serogroup B by Rt-multiplex PCR and the isolates were also confirmed by conventional methods. The CSF specimens with CT value > 35 could not be typed. We concluded that the Rt-multiplex PCR method is a rapid and reliable test for the direct diagnosis of acute bacterial meningitis due to NHS and serogrouping of N.meningitidis. Rapid diagnosis plays an important role for the treatment and control of the disease, and serogrouping of the agent plays an important role in terms of prevention/control and vaccination policies.

Nasal carriage rate and antibiotic susceptibility pattern of Neisseria meningitidis in healthy Ethiopian children and adolescents: A cross-sectional study.

BackgroundCommunity nasal meningococcal carriage rates are high across Africa. Meningococcal infections are major causes of morbidity and mortality in the continent; especially among children and adolescents. This study aimed to determine the prevalence of nasal carriage and antibiotic susceptibilities of meningococcal isolates from healthy Ethiopian children and adolescents.MethodA cross-sectional study was conducted in one of the sub-cities of Addis Ababa, Ethiopia. Nasal swabs were collected and processed for identification, serogrouping and testing susceptibilities for three antibiotics using standard microbiological techniques. Data on epidemiologic risk factors were collected using a structured questionnaire and the magnitude of their association with carriage was assessed using bivariate and multivariate analysis.ResultA total of 240 samples were collected (115 from males and 125 from females). The mean age of study participants was 11.1 years. The prevalence of nasal carriage for Neisseria meningitidis was 20.4% (49/240). Carriage was significantly higher among children living under crowded conditions (OR 1.268; 95% CI: 1.186–1.355; p = 0.006). The predominant serogroups were W135–20/49 isolates (40.8%) and C—12/49 isolates (24.5%) and 83.7% of meningococci were sensitive for Ciprofloxacin. In contrast, isolates showed high resistance to Ceftriaxone (69.4%) while only 4.2% were sensitive for Penicillin. Multi-drug resistance was documented for 14.3% of the isolates.ConclusionsMeningococcal carriage rate was found to be high with higher rates associated with children and adolescents living in crowded living conditions. Predominant isolates were of serogroup W135 and C and the isolates showed marked susceptibility to Ciprofloxacin and resistance to Ceftriaxone and Penicillin.

Phenotypic Characterization and Serotypes Identification of CSF isolates in Acute Bacterial Meningitis

Background and Aim: Bacterial meningitis is a fatal disabling disease which needs prompt antibiotic management. As it causes a significant morbidity and mortality throughout the world, every developing country should have accurate information regarding the common etiological agents in bacterial meningitis cases. In the present study, we have serotyped the obtained agents in order to predict the usefulness of existing vaccines against bacterial meningitis. Materials and Methods: Two thousand nineteen cerebrospinal fluid (CSF) samples were obtained prospectively from suspected meningitis from January 2011 to July 2013 out of which 76 cases were approved by cytological, microbiological, molecular, and biochemical analysis as per the standard techniques. The isolated bacteria were serotyped to determine the predominant strain. Results: On the whole, 2019 CSF samples were collected, and bacterial etiology was isolated in 76 cases; S. pneumoniae in 31.5%, N. meningitides in 18.4%, and H. influenza in 10.5% of culture positive samples. Gram stained smears were positive in 63 samples. Among pneumococcal meningitis the most common serotype was 1, (29 %), followed by 19F, (25%), 18F, (8.3%), 6, (16.6%), 14, (12.5%), and 20 (8.3%). Out of the N. meningitidis positive CSF samples, 35.7%, 21.4%, and 35.7%, belonged to serogroups A, C, and W-135, respectively, and one non-groupable isolate were involved as S. pneumoniae meningitis. In the H. influenzae group only serotype b (87.5%), and untypable, 1, (7.5%) cases have been identified. Only 17, (0.8%) soluble antigens were detected from culture negative CSF samples. High protein and low sugar levels associated well with the features of ABM. The mean sugar and protein level in the CSF samples were 22.3 ± 9.8 mg/dl, 85.3 ± 51.29 mg/dl, respectively. Conclusions: The isolation rate of bacteria causing meningitis is 3.8%. Out of the total pneumococcal serotypes three of them were not included in the current vaccine in Ethiopia. Unusual findings and high a proportion of serogroup W-135 meningococci are observed in our study area The role of clinical presentations, routine CSF analysis in the rapid diagnosis of acute bacterial meningitis in cases of negative gram stained smears and a good knowledge of the bacterial epidemiology of meningitis can serve as a guide to start a rapid treatment as early as possible. Recommendation: the result of this study can be used to improve the existing vaccines to cover the detected serotypes and consequently reduce the incidence of bacterial meningitis.

Meningococcal disease during the Hajj and Umrah mass gatherings.

The Hajj and Umrah religious mass gatherings hosted by the Kingdom of Saudi Arabia can facilitate the transmission of infectious diseases. The pilgrimages have been associated with a number of local and international outbreaks of meningococcal disease. These include serogroup A disease outbreaks in 1987 and throughout the 1990s and two international serogroup W135 outbreaks in 2000 and 2001. The implementation of strict preventative measures including mandatory quadrivalent meningococcal vaccination and antibiotic chemoprophylaxis for pilgrims from the African meningitis belt has prevented pilgrimage-associated meningococcal outbreaks since 2001. However, the fluid epidemiology of the disease and the possibility of outbreaks caused by serogroups not covered by the vaccine or emerging hyper-virulent strains, mean that the disease remains a serious public health threat during these events. Continuous surveillance of carriage state and the epidemiology of the disease in the Kingdom and globally and the introduction of preventative measures that provide broad and long-lasting immunity and impact carriage are warranted.

Meningococcal Disease in Korea: an Epidemiologic Study of the Underestimated Infectious Disease.

Meningococcal Disease in Korea: an Epidemiologic Study of the Underestimated Infectious Disease.

The Course of Generalized Meningococcal Infection Caused by Meningococcus Serogroup W135

The article describes the features of the course of generalized meningococcal infection caused by W135 serogroup meningococcus in children of various age groups. Taking into account the load of the disease course, especially in children of older age, vaccination by tetravalent (A, C, W, Y) conjugated vaccine is recommended not only for children of early age but also adolescents.

Trends and variations in the epidemiology of meningococcal disease in Kuwait 1987-2013.

The introduction of Haemophilus influenzae type b (Hib) conjugate vaccine and conjugate pneumococcal vaccine into routine childhood vaccination in Kuwait has resulted in the emergence of Neisseria meningitidis as the leading cause of invasive bacterial infection in children. Currently, a quadrivalent ACYW-135 meningococcal polysaccharide vaccine is administered as part of routine childhood vaccination in Kuwait at the age of 2 years. Conjugate meningococcal vaccines have been shown to be more effective in preventing meningococcal infection in young children. The objective of this study was to describe the epidemiology of meningococcal disease (MD) in Kuwait and evaluate the need for conjugate vaccine in routine childhood immunization. We have reviewed the MD surveillance data from the communicable disease unit, Ministry of Health, Kuwait during the period from 1987 to 2013. The analysis included microbiologically confirmed cases of N. meningitidis in the blood and cerebrospinal fluid. There were 293 cases of confirmed MD during the study period. Two hundred and four cases (70%) were in children ≤ 14 years of age. The mean incidence rate was 0.5/100,000 persons. The dominant serogroups were W-135 and B, accounting for 80 cases (32%) each. Serogroup B accounted for 69/204 (34%) of all cases in children ≤ 14 years and serogroup A accounted for 36/89 40% of all adult cases. There were three outbreaks: 1987 (caused by serogroup A), 1989 (caused by serogroup W-135) and 2002 (caused by serogroup B). The mean case fatality rate was 13.5%. In conclusion, despite childhood routine vaccination with ACYW-135 polysaccharide vaccine, infants and young children remain at high risk for MD, which supports the introduction of conjugate meningococcal vaccine to the routine childhood vaccination schedule.

Prevalence of meningococcal meningitis in China from 2005 to 2010

BackgroundWe aimed to estimate the prevalence and epidemiologic characteristics of meningococcal meningitis (MM) in mainland China (excluding Taiwan, Hong Kong, and Macau) and to provide reference data for controlling the outbreak and prevalence of MM. MethodsData from the National Notifiable Diseases Registry System and the MM case information reporting system from 2005 to 2010 as well as data from the MM Surveillance System were used. ResultsThe morbidity of MM for the whole country was, on average, 0.09 cases per 100,000 (range 0.02 [2010]–0.18 [2005] cases per 100,000) from 2005 to 2010, the incidence rate was highest in the Xinjiang autonomous region (average 0.56 cases per 100,000), and the majority of cases came from Anhui province (average 0.32 cases per 100,000). Morbidity was highest in children under 1 year old (average 0.60 cases per 100,000). The proportion of laboratory-confirmed cases of serogroups A, B, and C were 37.2, 11.5 and 42.7, respectively, from 2005 to 2010. ConclusionsThe incidence level declined year-to-year in mainland China. Children and students are the most at risk groups. The proportion of serogroup C cases has increased year-to-year, and new cases of serogroup W135 have been found. Controlling the epidemic of serogroup C and preventing outbreaks of serogroup B and W135 represent major future challenges.

Meningitis caused by Neisseria Meningitidis, Hemophilus Influenzae Type B and Streptococcus Pneumoniae during 2005–2012 in Turkey

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.

Enhanced surveillance of invasive meningococcal disease in Canada, 2006-2011.

The purpose of this report is to describe the epidemiology of invasive meningococcal disease (IMD) in Canada from 2006 to 2011. Data from the Enhanced Invasive Meningococcal Disease Surveillance System and national population estimates were selected for descriptive and inferential analyses. The geographic, demographic, seasonal and subtype distributions as well as clinical characteristics of the IMD cases were examined. Incidence and mortality rates were calculated per 100,000 population per year; 95% confidence intervals (CI) were calculated for rate comparison. The direct method was used for age standardization. Proportions were compared using the chi-squared test at a p<0.05 significance level. During the study period, the mean incidence rates of IMD were 0.58 (total), 0.33 (serogroup B), 0.07 (serogroup C), 0.03 (serogroup W-135) and 0.10 (serogroup Y). The median age for serogroups B, C, W-135 and Y was 16, 43, 38 and 47 years respectively. The mean age-specific incidence rates among infants under 1 year of age (7.35, CI: 5.38-9.32) and children from 1 to 4 years of age (1.89, CI: 1.54-2.24) were significantly higher than those in any other age group. The mean case fatality ratio was 8.1% (range 4.3%-14.3%). The average number of cases that occurred per month was significantly higher (p<0.0001) in winter (18 cases) than in summer (12 cases). IMD is still endemic in Canada. Although individuals at any age can be affected, infants under 1 year of age are at the greatest risk, followed by children aged 1-4 years and individuals aged 15-19 years. Following the implementation of routine childhood immunization programs with monovalent meningococcal C conjugate vaccines (MenC) in all provinces and territories (beginning in 2007), the incidence of serogroup C has decreased significantly over the study period and is now at an all-time low. Serogroup B is the leading cause of IMD, and diseases of serogroup W-135 and Y have stabilized at relatively lower incidence rates. With the addition of immunization programs using quadrivalent conjugate meningococcal vaccines (MCV4), we would expect further reductions in the incidence of meningococcal infection in Canada.

Crystallographic analysis of Neisseria meningitidis PorB extracellular loops potentially implicated in TLR2 recognition.

Among all Neisseriae species, Neisseria meningitidis and Neisseria gonorrhoeae are the only human pathogens, causative agents of bacterial meningitis and gonorrhoea, respectively. PorB, a pan-Neisseriae trimeric porin that mediates diffusive transport of essential molecules across the bacterial outer membrane, is also known to activate host innate immunity via Toll-like receptor 2 (TLR2)-mediated signaling. The molecular mechanism of PorB binding to TLR2 is not known, but it has been hypothesized that electrostatic interactions contribute to ligand/receptor binding. Strain-specific sequence variability in the surface-exposed loops of PorB which are potentially implicated in TLR2 binding, may explain the difference in TLR2-mediated cell activation in vitro by PorB homologs from the commensal Neisseriae lactamica and the pathogen N. meningitidis. Here, we report a comparative structural analysis of PorB from N. meningitidis serogroup B strain 8765 (63% sequence homology with PorB from N. meningitidis serogroup W135) and a mutant in which amino acid substitutions in the extracellular loop 7 lead to significantly reduced TLR2-dependent activity in vitro. We observe that this mutation both alters the loop conformation and causes dramatic changes of electrostatic surface charge, both of which may affect TLR2 recognition and signaling.