Characterization of Carriage Isolates of Neisseria meningitides in the Adolescents and Young Adults Population of Bogota (Colombia) (original) (raw)
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Prevalence of meningococcal carriage in children and adolescents aged 10–19 years in Chile in 2013
Journal of Infection and Public Health, 2016
In 2011, Chile experienced an increase in the number of cases of IMD caused by Neisseria meningitidis group W. This epidemiological scenario prompted authorities to implement prevention strategies. As part of these strategies, the Institute of Public Heath of Chile conducted a cross-sectional study to determine the prevalence of pharyngeal carriage of N. meningitidis in a representative sample of healthy children and adolescents aged 10-19 years. The identification of presumptive N. meningitidis strains was performed by testing carbohydrate utilization in the National Reference Laboratory at the ISP. Association of meningococcal carriage with risk factors was analyzed by calculating the Odds Ratio. Selected variables were included in a logistic model for risk analyses. The prevalence of carriage of N. meningitidis was 6.5% (CI: 5.7-7.3%). Older age (carriers: 14.2 ± 0.29 vs. non-carriers: 13.8 ± 0.08 years old; p = 0.009), cohabitation with children (carriers: 0.9 ± 0.13 vs. non-carriers: 0.7 ± 0.03; p = 0.028), number of smoking cohabitants (carriers: 0.55 ± 0.13 vs. non-carriers: 0.44 ± 0.03) and frequent attendance to crowded social venues (carriers: 49% vs.
The Pediatric infectious disease journal, 2015
In 2010, introduction of the meningococcal C conjugate vaccine in Brazil for children < 2 years providing an immediate reduction in the incidence rates of disease among the age groups targeted for the vaccine, but no impact was observed in unvaccinated age groups. Knowledge about meningococcal carriage is crucial for improving our understanding of the disease epidemiology, as well as for designing effective vaccination programs. Taking in account the very limited published data currently available describing meningococcal carriage in Brazil, we performed a study to evaluate the prevalence of N. meningitidis carriage among adolescent students. A cross-sectional study was conducted in 2012 to assess the prevalence of meningococcal carriage among a representative sample of 1,208 students 11-19 years of age in Campinas, Brazil. Genotypic and phenotypic characterization of isolated carriage strains and the effect of potential risk factors for carriage were also analyzed. The overall c...
Journal of Clinical Microbiology, 2014
Neisseria meningitidis is an obligate human commensal that commonly colonizes the oropharyngeal mucosa. Carriage is age dependent and very common in young adults. The relationships between carriage and invasive disease are not completely understood. In this work, we performed a longitudinal carrier study in adolescents and young adults (173 subjects). Overall, 32 subjects (18.5%) had results that were positive for meningococcal carriage in at least one visit (average monthly carriage rate, 12.1%). Only five subjects tested positive at all four visits. All meningococcal isolates were characterized by molecular and serological techniques. Multilocus sequence typing, PorA typing, and sequencing of the 4CMenB vaccine antigens were used to assess strain diversity. The majority of positive subjects were colonized by capsule null (34.4%) and capsular group B strains (28.1%), accounting for 23.5% and 29.4% of the total number of isolates, respectively. The fHbp and nhba genes were present in all isolates, while the nadA gene was present in 5% of the isolates. The genetic variability of the 4CMenB vaccine antigens in this collection was relatively high compared with that of other disease-causing strain panels. Indications about the persistence of the carriage state were limited to the time span of the study. All strains isolated from the same subject were identical or cumulated minor changes over time. The expression levels and antigenicities of the 4CMenB vaccine antigens in each strain were analyzed by the meningococcal antigen typing system (MATS), which revealed that expression can change over time in the same individual. Future analysis of antigen variability and expression in carrier strains after the introduction of the MenB vaccine will allow for a definition of its impact on nasopharyngeal/oropharyngeal carriage.
Prevalence of Neisseria meningitidis carriers in the school population of Catalonia, Spain
Epidemiology and Infection, 2001
The aim of this study was to determine the prevalence of healthy Neisseria meningitidis pharyngeal carriers in a representative sample of the Catalonian school population, as well as its associated factors. The sample was divided into age groups: [les ]5, 6–7 and 13–14 years old. Parents were given a questionnaire to collect information on sociodemographic and epidemiological variables. Oropharyngeal swabs were collected with a cotton-tipped swab in an Amies transport medium and cultured on Thayer Martin plates at 35 °C in 5% CO2. The isolates were serogrouped and sero/subtyped. Of the 1406 children studied, 75 (5·34%) meningococcal carriers were detected: 63 B (4·5%), 9 non groupable (0·7%), 2 29E (0·1%) and 1X (0·07%). No serogroup C meningococci were found in this study, probably due to the high A+C vaccination coverage of up to 68·9% in children 6–7 years old. Bivariate analysis identified six statistically significant risk factors for meningococcal carriage: increasing age, rec...
Objective. To carry out a pilot study to discover the frequency of colonization in healthy children under five years old and teenagers, as well as the distribution of the different N. meningitidis serogroups isolated from nasopharyngeal samples collected from the population under study. Material and Methods. The population included youth between 15 and 19 years old living in social rehabilitation centers (SRC) and university teenagers (UT) as well as children under the age of five attending day care centers (DCC) in Mexico City. Nasopharyngeal exudates were processed using standard microbiological techniques in order to identify Nm, the serogroup, type and subtype of these isolates. Results. A total of 2 310 samples (774 SRC, 800 UT and 736 DCC) were taken. Total prevalence of Nm was 1.6 per cent. In teenagers living in SRC the prevalence was 2.9%. The most frequent serogroups were Y (29.7%), C (24.3%) and B (10.8%). Conclusions. The prevalence of carriers in the study environment was significant (1.6%) and similar to countries in which the invasive illness is much more frequent.
Epidemiology and Infection, 2001
We analysed a strain collection representative of the overall Neisseria meningitidis population circulating in an open community (46 000 inhabitants, Spain) during an endemic period (30 isolates from patients and 191 from throat cultures of healthy individuals) by both phenotypic and molecular techniques. Almost all patient isolates were assigned to three hyper-virulent lineages (ET-5 complex, ET-37 complex and cluster A4) by both multilocus enzyme electrophoresis (MEE) and pulsed-field gel electrophoresis (PFGE). In contrast, MEE and PFGE assigned 20 % and 15 % respectively of carrier isolates to the hyper-virulent clones (4 % for both methods together). There was also a higher correlation between PFGE and phenotypes associated with virulent clones. These notable differences between the two molecular methods were further observed in more than half the carrier isolates, suggesting that the associations between these strains were distorted by recombination events. However, almost one-third of total endemic strains from symptom-free carriers and almost all patient strains belonged to clones defined by MEE and PFGE, with no known epidemiological connection. These data indicate low transmission and a weak clonal structure for N. meningitidis.
Genetic Analysis of Meningococci Carried by Children and Young Adults
The Journal of Infectious Diseases, 2005
Background. Neisseria meningitidis is a diverse commensal bacterium that occasionally causes severe invasive disease. The relationship between meningococcal genotype and capsular polysaccharide, the principal virulence factor and vaccine component, was investigated in carried meningococci isolated from 8000 children and young adults in Bavaria, Germany. Methods. Of the 830 meningococci isolated (carriage rate, 10.4%) by microbiological techniques, 822 were characterized by serogrouping, multilocus sequence typing, and genetic analysis of the capsule region. Statistical and population genetic analyses were applied to these data. Results. The rapid increase in carriage rates with age of carrier, the low prevalence of hyperinvasive meningococci, and the relative prevalence of the 4 disease-associated serogroups were consistent with earlier observations. There was no genetic structuring of the meningococcal population by age of carrier or sampling location; however, there was significant geographic structuring of the meningococci isolated in civil, but not military, institutions. The rate of capsule gene expression did not vary with age of carrier or meningococcal genotype, except for serogroup C, for which increased expression was associated with ST-11 (formerly ET-37) complex meningococci. Conclusions. Serogroup C capsule expression during carriage may contribute to the invasive character of ST-11 complex meningococci and to the high efficacy of meningococcal serogroup C conjugate polysaccharide vaccine.
PLOS ONE, 2021
Background Neisseria meningitidis (Nm) pharyngeal carriage is a necessary condition for invasive disease. We present the first carriage study in children in Buenos Aires, Argentina, considering 2017 as a transition year. Aims: to assess the rate of Nm carriage, to determine genogroup, clonal complex and outer membrane protein distribution, to determine carriage risk factors by age. Methods Cross-sectional study including children 1–17 yrs, at Ricardo Gutiérrez Children’s Hospital in Buenos Aires 2017. Oro-pharyngeal swabs were taken and cultured within a short time after collection. Genogroup was determined by PCR and clonal complex by MLST. Categorical variables were analyzed. Results A total of 1,751 children were included. Group 1: 943 children 1–9 yrs, 38 Nm were isolated; overall carriage 4.0%. Genogroup distribution: B 26.3%, W 5.3%, Y 2.6%, Z 5.3%, other groups 7.9% and capsule null (cnl) 52.6%. Participating in extracurricular activities was the only independent predictor of...