Effect of smoking on meningococcal carriage

Carriage of Neisseria meningitidis Among Umrah Pilgrims: Circulating Serogroups and Antibiotic Resistance

Background

Meningococcal disease and outbreaks are a risk during mass gatherings such as the Umrah religious pilgrimage to the Kingdom of Saudi Arabia (KSA). We aimed to investigate the carriage of Neisseria meningitidis among the 2019 Umrah pilgrims and determine the circulating serogroups and their antibiotic susceptibility profiles.

Methods

We conducted a cross-sectional study among adult Umrah pilgrims from 17th to 29th April 2019 in Mecca city, KSA. A questionnaire was administered to each participant, and an oropharyngeal swab was obtained. Microbiological techniques were used to isolate, identify and serogroup N. meningitidis from the swabs. E-tests were used to determine the susceptibility of the isolates to nine antibiotics.

Results

The study enrolled 616 pilgrims from 17 countries with a mean age of 53.8 years (±13.1, range = 19–91) and a male-to-female ratio of 1.1:1. Nearly 39% of the respondents had no formal education, 32.5% declared having an underlying health condition and 17.2% were current or past smokers. During their Umrah stay, most pilgrims reported sharing accommodation (98.5%) and never using a face mask (98.5%). Also, 34.6% reported suffering from influenza-like symptoms and 11.8% used antibiotics. N. meningitidis was isolated from three pilgrims (carriage rate of 0.49%), two were serogroup A and one was serogroup B. Antibiotic susceptibility results were available for one isolate (serogroup B) which showed resistance to ciprofloxacin and decreased susceptibility to trimethoprim-sulfamethoxazole.

Conclusion

Carriage of N. meningitidis among Umrah pilgrims was low. However, invasive serogroups were identified, including an isolate resistant to ciprofloxacin used for chemoprophylaxis. Meningococcal disease preventive measures for Umrah should be regularly reviewed and updated accordingly to reduce the risk of the disease and future pilgrimage-associated outbreaks.

Risk factors for carriage of meningococcus in third-level students in Ireland: an unsupervised machine learning approach

The aim of this study was to examine the risk factors for pharyngeal carriage of meningococci in third-level students using an unsupervised machine learning approach. Data were gathered as part of meningococcal prevalence studies conducted by the Irish Meningitis and Sepsis Reference Laboratory (IMSRL). Pharyngeal swab cultures for meningococcal carriage were taken from each student once they had completed a single-page anonymous questionnaire addressing basic demographics, social behaviors, living arrangements, vaccination, and antibiotic history. Data were analyzed using multiple correspondence analysis through a machine learning approach.In total, 16,285 students who had a pharyngeal throat swab taken returned a fully completed questionnaire. Overall, meningococcal carriage rate was 20.6%, and the carriage of MenW was 1.9% (n = 323). Young Irish adults aged under 20 years and immunized with the meningococcal C vaccine had a higher MenW colonization rate (n = 171/1260, 13.5%) compared with non-Irish adults aged 20 years or older without the MenC vaccine (n = 5/81, 6%, chi-square = 3.6, p = .05). Unsupervised machine learning provides a useful technique to explore meningococcal carriage risk factors. The issue is very complex, and asked risk factors only explain a small proportion of the carriage. This technique could be used on other conditions to explore reasons for carriage.

Cumulative annual coverage of meningococcal B vaccination in Australian general practice for three at-risk groups, 2014 to 2019

Neisseria meningitidis serogroup B (MenB) is the most common cause of meningococcal disease in adolescents and young adults. In Australia, MenB vaccination has been available through private prescription since 2014 and has been recommended for at-risk groups including adolescents, young adults who smoke and people medically at risk. For each of these at-risk groups, we estimated cumulative annual coverage of MenB vaccination between 2014 and 2019. We also evaluated factors associated with vaccination coverage in 2019. Our analyses used electronic health records in the national MedicineInsight database for people regularly attending general practices. Cumulative vaccination coverage increased among the at-risk groups between 2014 and 2019: from 0.09% to 1.65% for adolescents, from 0.01% to 0.15% for young adults who smoke, and from 0.35% to 12.09% for people medically at risk. However, vaccination coverage in 2019 remained very low across these groups. Data sparsity prevented the evaluation of factors associated with vaccination coverage for smokers. We observed variation in the relative risk of being vaccinated by age, sex, socioeconomic and clinical factors for adolescents and people medically at risk. Still, the absolute magnitude of coverage was low across all subgroups examined, and indicates a need for strategies to increase vaccination uptake among at-risk groups irrespective of patient and practice characteristics. Our study provides baseline data for monitoring menB vaccination uptake among recommended groups in light of limited national data, especially for medically at-risk groups.

Oropharyngeal meningococcal carriage in children and adolescents, a single center study in Buenos Aires, Argentina

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 Nm carriage. Group 2: 808 children 10–17 yrs, 76 Nm were isolated; overall carriage 9.4%. Genogroup distribution: B 19.7%, C 5.3%, W 7.9%, Y 9.2%, Z 5.3%, other groups 7.9% and cnl 44.7%. Independent predictors of carriage: attending pubs/night clubs and passive smoking (adjusted OR: 0.55, 95%CI = 0.32–0.93; p = 0.025).

Conclusions

Overall carriage was higher in 10–17 yrs. The isolates presenting the cnl locus were prevalent in both age groups and genogroup B was the second most frequent.

Tobacco smoking and meningococcal disease in adolescents and young adults: a systematic review and meta-analysis

OBJECTIVES

Systematically review the evidence on the association between active and passive tobacco smoking and invasive meningococcal disease (IMD) in adolescents and young adults aged 15-to-24-years.

METHODS

Electronic searches were conducted in Ovid MEDLINE, EMBASE, and Web of Science to June 2020. Reference lists were hand-searched. Two independent reviewers screened articles for eligibility. Risk of bias was assessed using an adapted Risk of Bias in Non-Randomised Studies - of Interventions tool. Meta-analyses were conducted using random-effects models.

RESULTS

Of 312 records identified, 13 studies were included. Five studies provided data on the association between active smoking and IMD in the target age group; pooled odds ratio (OR): 1.45 (95% CI: 0.93-2.26). The overall OR, including eight studies with a wider participant age range, was 1.45 (95% CI: 1.12-1.88). For passive smoking, the equivalent ORs were 1.56 (95% CI: 1.09-2.25) and 1.30 (95% CI: 1.06-1.59) respectively. All studies were at high risk of bias.

CONCLUSIONS

Active and passive smoking may be associated with IMD in adolescents and young adults. Since active smoking has also been linked to meningococcal carriage, and passive smoking to IMD in young children, smoking cessation should be encouraged to reduce transmission and IMD risk in all ages.

UKMenCar4: A cross-sectional survey of asymptomatic meningococcal carriage amongst UK adolescents at a period of low invasive meningococcal disease incidence

Carriage of Neisseria meningitidis, the meningococcus, is a prerequisite for invasive meningococcal disease (IMD), a potentially devastating infection that disproportionately afflicts infants and children. Humans are the sole known reservoir for the meningococcus, and it is carried asymptomatically in the nasopharynx of ~10% of the population. Rates of carriage are dependent on age of the host and social and behavioural factors. In the UK, meningococcal carriage has been studied through large, multi-centre carriage surveys of adolescents in 1999, 2000, and 2001, demonstrating carriage can be affected by immunisation with the capsular group C meningococcal conjugate vaccine, inducing population immunity against carriage. Fifteen years after these surveys were carried out, invasive meningococcal disease incidence had declined from a peak in 1999.  The UKMenCar4 study was conducted in 2014/15 to investigate rates of carriage amongst the adolescent population during a period of low disease incidence. The protocols and methodology used to perform UKMenCar4, a large carriage survey, are described here.

UKMenCar4: A cross-sectional survey of asymptomatic meningococcal carriage amongst UK adolescents at a period of low invasive meningococcal disease incidence

Carriage of Neisseria meningitidis, the meningococcus, is a prerequisite for invasive meningococcal disease (IMD), a potentially devastating infection that disproportionately afflicts infants and children. Humans are the sole known reservoir for the meningococcus, and it is carried asymptomatically in the nasopharynx of ~10% of the population. Rates of carriage are dependent on age of the host and social and behavioural factors. In the UK, meningococcal carriage has been studied through large, multi-centre carriage surveys of adolescents in 1999, 2000, and 2001, demonstrating carriage can be affected by immunisation with the capsular group C meningococcal conjugate vaccine, inducing population immunity against carriage. Fifteen years after these surveys were carried out, invasive meningococcal disease incidence had declined from a peak in 1999.  The UKMenCar4 study was conducted in 2014/15 to investigate rates of carriage amongst the adolescent population during a period of low disease incidence. The protocols and methodology used to perform UKMenCar4, a large carriage survey, are described here.

Meningococcal pneumonia: a review

Background

Although Neisseria meningitidis is one of the major causes of meningitis, meningococcal pneumonia is the most common non-neurological organ disease caused by this pathogen.

Methods

We conducted a review of the literature to describe the risk factors, pathogenesis, clinical features, diagnosis, treatment and prevention of meningococcal pneumonia.

Results

Meningococcal pneumonia was first described in 1907 and during the 1918–1919 influenza pandemic large numbers of cases of meningococcal pneumonia occurred in patients following the initial viral infection. A number of publications, mainly case series or case reports, has subsequently appeared in the literature. Meningococcal pneumonia occurs mainly with serogroups Y, W-135 and B. Risk factors for meningococcal pneumonia have not been well characterised, but appear to include older age, smoking, people living in close contact (e.g. military recruits and students at university), preceding viral and bacterial infections, haematological malignancies, chronic respiratory conditions and various other non-communicable and primary and secondary immunodeficiency diseases. Primary meningococcal pneumonia occurs in 5–10% of patients with meningococcal infection and is indistinguishable clinically from pneumonia caused by other common pathogens. Fever, chills and pleuritic chest pain are the most common symptoms, occurring in > 50% of cases. Productive sputum and dyspnoea are less common. Diagnosis of meningococcal pneumonia may be made by the isolation of the organism in sputum, blood, or normally sterile site cultures, but is likely to underestimate the frequency of meningococcal pneumonia. If validated, PCR-based techniques may be of value for diagnosis in the future. While penicillin was the treatment of choice for meningococcal infection, including pneumonia, prior to 1991, a third generation cephalosporin has been more commonly used thereafter, because of concerns of penicillin resistance. Chemoprophylaxis, using one of a number of antibiotics, has been recommended for close contacts of patients with meningococcal meningitis, and similar benefits may be seen in contacts of patients with meningococcal pneumonia. Effective vaccines are available for the prevention of infection with certain meningococcal serogroups, but this field is still evolving.

Conclusion

Meningococcal pneumonia occurs fairly frequently and should be considered as a possible cause of pneumonia, particularly in patients with specific risk factors.

The effect of passive smoking on bacterial colonisation of the upper airways and selected laboratory parameters in children

Exposure to tobacco smoke is associated with a higher risk of respiratory tract diseases. The aim of this study was to determine the influence of passive smoking on selected characteristics of children with adenoid hypertrophy. Sixty-one children with adenoid hypertrophy were enrolled in the prospective study. Differences in bacterial colonisation of middle nasal meatus and nasopharynx and changes in selected laboratory immune and inflammatory markers according to the tobacco smoke exposure were analysed. Exposure to tobacco smoke was associated with significantly higher colonisation of pathogenic bacteria and polymicrobial growth of pathogenic bacteria (≥ 2 bacteria) in middle nasal meatus compared to non-exposed children (P = 0.045, P = 0.032, respectively). Identification of pathogenic bacteria in the middle nasal meatus did not correlate with isolation of pathogenic bacteria in the nasopharynx in either group of children. Parameters of humoral immunity in serum, IgA and IgG, were detected at higher concentrations in children exposed to tobacco smoke (P = 0.047, P = 0.031, respectively). Differences in selected parameters of cellular immunity in peripheral blood according to passive smoking were not observed. Tobacco smoke exposure is related to increased colonisation by pathogenic bacteria in middle nasal meatus and elevation of IgA and IgG in peripheral blood, but does not seem to influence markers of cellular immunity parameters in children with adenoid hypertrophy. Avoidance of passive smoking could be recommended as a universal preventive strategy against microbial colonisation of the upper airways and development of various inflammatory diseases in children, e.g. adenoid hypertrophy.

Location, Location, Location-Commensalism, Damage and Evolution of the Pathogenic Neisseria

The 10 human-restricted Neisseria species all colonize mucosal surfaces, but show a spectrum of pathogenicity. The commensal Neisseria do not normally cause pathology, while the two pathogenic species, Neisseria meningitidis and Neisseria gonorrhoeae, straddle the border between commensalism and pathogenicity. Why the pathogenic Neisseria continue to mediate host damage after thousands of years of co-evolution with their human host, and why the commensal species have not acquired the ability to damage the host, if this capability provides a selective advantage, is not understood. One way the pathogenic species are different from the commensal species is by their ability to induce PMN inflammation, which is dependent on the site of colonization. I discuss how the site of colonization dictates whether copious inflammation occurs with both pathogenic species. I put forth a model that posits that an ancestor of both pathogenic species changed colonization site from the oral cavity to the genital tract of a human or humanoid and had to evolve multiple, new traits - to induce PMN inflammation and avoid adaptive immunity - to allow efficient sexual transmission. This model predicts that PMN inflammation produces the serious sequelae of gonorrhea and increases the probability that N. meningitidis might exit the oral cavity to produce systemic disease. In both cases, the pathology produced by these host-adapted species is an unintended by product of the inflammation but host damage does not provide any selective advantage for these organisms.

Risk factors for acquisition of meningococcal carriage in the African meningitis belt

OBJECTIVE

To investigate potential risk factors for acquisition in seven countries of the meningitis belt.

METHODS

Households were followed up every 2 weeks for 2 months, then monthly for a further 4 months. Pharyngeal swabs were collected from all available household members at each visit and questionnaires completed. Risks of acquisition over the whole study period and for each visit were analysed by a series of logistic regressions.

RESULTS

Over the course of the study, acquisition was higher in: (i) 5-to 14-year olds, as compared with those 30 years or older (OR 3.6, 95% CI 1.4-9.9); (ii) smokers (OR 3.6, 95% CI 0.98-13); and (iii) those exposed to wood smoke at home (OR 2.6 95% CI 1.3-5.6). The risk of acquisition from one visit to the next was higher in those reporting a sore throat during the dry season (OR 3.7, 95% CI 2.0-6.7) and lower in those reporting antibiotic use (OR 0.17, 95% CI 0.03-0.56).

CONCLUSIONS

Acquisition of meningococcal carriage peaked in school age children. Recent symptoms of sore throat during the dry season, but not during the rainy season, were associated with a higher risk of acquisition. Upper respiratory tract infections may be an important driver of epidemics in the meningitis belt.

Meningococcal Carriage Evaluation in Response to a Serogroup B Meningococcal Disease Outbreak and Mass Vaccination Campaign at a College-Rhode Island, 2015-2016

Background

Serogroup B meningococcal disease caused 7 US university outbreaks during 2013-2016. Neisseria meningitidis can be transmitted via asymptomatic nasopharyngeal carriage. MenB-FHbp (factor H binding protein), a serogroup B meningococcal (MenB) vaccine, was used to control a college outbreak. We investigated MenB-FHbp impact on meningococcal carriage.

Methods

Four cross-sectional surveys were conducted in conjunction with MenB-FHbp vaccination campaigns. Questionnaires and oropharyngeal swabs were collected from students. Specimens were evaluated using culture, slide agglutination, real-time polymerase chain reaction (rt-PCR), and whole genome sequencing. Adjusted prevalence ratios (aPRs) were calculated using generalized estimating equations.

Results

During each survey, 20%-24% of participants carried any meningococcal bacteria and 4% carried serogroup B by rt-PCR. The outbreak strain (ST-9069) was not detected during the initial survey; 1 student carried ST-9069 in the second and third surveys. No carriage reduction was observed over time or with more MenB-FHbp doses. In total, 615 students participated in multiple surveys: 71% remained noncarriers, 8% cleared carriage, 15% remained carriers, and 7% acquired carriage. Ten students acquired serogroup B carriage: 3 after 1 MenB-FHbp dose, 4 after 2 doses, and 3 after 3 doses. Smoking (aPR, 1.3; 95% confidence interval [CI], 1.1-1.5) and male sex (aPR, 1.3; 95% CI, 1.1-1.5) were associated with increased meningococcal carriage.

Conclusions

Carriage prevalence on campus remained stable, suggesting MenB-FHbp does not rapidly reduce meningococcal carriage or prevent serogroup B carriage acquisition. This reinforces the need for high vaccination coverage to protect vaccinated individuals and chemoprophylaxis for close contacts during outbreaks.

Risk factors for community-acquired bacterial meningitis

BACKGROUND

Bacterial meningitis is a significant burden of disease and mortality in all age groups worldwide despite the development of effective conjugated vaccines. The pathogenesis of bacterial meningitis is based on complex and incompletely understood host-pathogen interactions. Some of these are pathogen-specific, while some are shared between different bacteria.

METHODS

We searched the database PubMed to identify host risk factors for bacterial meningitis caused by the pathogens Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae type b, because they are three most common causative bacteria beyond the neonatal period.

RESULTS

We describe a number of risk factors; including socioeconomic factors, age, genetic variation of the host and underlying medical conditions associated with increased susceptibility to invasive bacterial infections in both children and adults.

CONCLUSIONS

As conjugated vaccines are available for these infections, it is of utmost importance to identify high risk patients to be able to prevent invasive disease.

Meningococcal Carriage in Military Recruits and University Students during the Pre MenB Vaccination Era in Greece (2014-2015)

Purpose

The aim of the study was to estimate the meningococcal carriage rate and to identify the genotypic characteristics of the strains isolated from healthy military recruits and university students in order to provide data that might increase our understanding on the epidemiology of meningococcus and obtain information which helps to evaluate the potential effects on control programs such as vaccination.,

Methods

A total of 1420 oropharyngeal single swab samples were collected from military recruits and university students on voluntary basis, aged 18–26 years. New York City Medium was used for culture and the suspected N. meningitidis colonies were identified by Gram stain, oxidase and rapid carbohydrate utilization tests. Further characterisation was carried out by molecular methods (multiplex PCR, MLST, WGS).

Results

The overall carriage rate was of 12.7%; 15% and 10.4% for recruits and university students respectively. MenB (39.4%) was the most prevalent followed by MenY (12.8%) and MenW (4.4%). Among the initial 76 Non Groupable (NG) isolates, Whole Genome Sequence Analysis (WGS) revealed that 8.3% belonged to MenE, 3.3% to MenX and 1.1% to MenZ, while, 53 strains (29.4%) were finally identified as capsule null. Genetic diversity was found among the MenB isolates, with 41/44 cc and 35 cc predominating.

Conclusion

Meningococcal carriage rate in both groups was lower compared to our previous studies (25% and 18% respectively) with predominance of MenB isolates. These findings, help to further our understanding on the epidemiology of meningococcal disease in Greece. Although the prevalence of carriage seems to have declined compared to our earlier studies, the predominant MenB clonal complexes (including 41/44cc and 35cc) are associated with invasive meningococcal disease.

Meningococcal Carriage among Adolescents after Mass Meningococcal C Conjugate Vaccination Campaigns in Salvador, Brazil

Neisseria meningitidis is a commensal bacterium of the human nasopharynx. In rare cases, it penetrates the mucosa, entering the blood stream and causing various forms of disease. Meningococcal conjugate vaccines can prevent invasive disease not only by direct effect in vaccinated individuals but also by herd protection, preventing acquisition of carriage, which interrupts transmission and leads to protection of unvaccinated persons. In 2010 in Salvador, Brazil, an outbreak of group C meningococcal disease led to a mass meningococcal serogroup C conjugate vaccination drive, targeting those <5 and 10–24 years of age. The present study aimed to estimate the prevalence of and identify factors associated with N. meningitidis carriage among adolescents from Salvador, Brazil, in the post-vaccination period. In spring 2014, we performed a cross-sectional study involving 1,200 public school students aged 11–19 years old. Oropharyngeal swabs were collected to identify N. meningitidis. Of the 59 colonized participants, 36 (61.0%) carried non-groupable N. meningitidis, while genogroup B (11.9%), Y (8.5%), E (6.8%), Z (5.1%), C (3.4%), and W (3.4%) were also detected. The overall prevalence of N. meningitidis carriage was 4.9% (95% confidence interval [CI], 3.6–6.1%); the prevalence of N. meningitidis genogroup C was 0.17% (95% CI, 0.0–0.40%). There was no difference by age. Factors associated with carriage were having only one, shared, bedroom in the household (PR, 2.02; 95% CI, 0.99–4.12, p = 0.05); the mother being the only smoker in the home (PR, 2.48; 95% CI, 1.16–5.29; p = 0.01); and going to pubs/parties more than 5 times/month (PR, 2.61; 95% CI, 1.38–4.92; p = 0.02). Our findings show that the N. meningitidis carriage rate in adolescents from Salvador, Bahia, is low and is potentially influenced by the low prevalence of N. meningitidis genogroup C. However, continued surveillance is important to identify changes in the dynamics of N. meningitidis, including the emergence of diseases due to a non-C serogroup.

Variations in Neisseria meningitidis carriage by socioeconomic status: a cross-sectional study

BACKGROUND

Deprivation is associated with an increased risk of invasive Neisseria meningitidis disease, but little is known about the relationship between deprivation and asymptomatic carriage of N. meningitidis. This analysis was conducted to examine the relationship between meningococcal carriage and deprivation.

METHODS

As part of a rapid meningococcal carriage prevalence study conducted in West Cumbria to investigate an apparent cluster of invasive meningococcal disease, data were collected on lifestyle and social factors, including area-level indicators of socioeconomic status, to identify factors associated with meningococcal carriage.

RESULTS

In a multivariable log binomial regression model adjusted for age, lower socioeconomic status was significantly associated with higher prevalence of meningococcal carriage. A 1-unit increase in Index of Multiple Deprivation (2010) score was associated with a 1.7% increase in meningococcal carriage prevalence (95% confidence interval 0.3-3.0%). Age was the only significant predictor of carriage of Neisseria lactamica.

CONCLUSIONS

Living in a deprived area is associated with increased carriage of Group B meningococcus. Deprivation is an important factor to consider in the evaluation of the effectiveness and cost-effectiveness of the introduction of new meningococcal B vaccines and the development and implementation of immunization policies. Further work is required to understand whether deprivation has an effect on meningococcal carriage through other factors such as smoking.

Meningococcal carriage among Georgia and Maryland high school students

BACKGROUND

Meningococcal disease incidence in the United States is at an all-time low. In a previous study of Georgia high school students, meningococcal carriage prevalence was 7%. The purpose of this study was to measure the impact of a meningococcal conjugate vaccine on serogroup Y meningococcal carriage and to define the dynamics of carriage in high school students.

METHODS

This was a prospective cohort study at 8 high schools, 4 each in Maryland and Georgia, during a school year. Students at participating schools received quadrivalent meningococcal conjugate vaccine that uses diphtheria toxoid as the protein carrier (MCV4-DT). In each state, 2 high schools were randomly assigned for MCV4-DT receipt by students at the beginning of the study, and 2 were randomly assigned for MCV4-DT receipt at the end. Oropharyngeal swab cultures for meningococcal carriage were performed 3 times during the school year.

RESULTS

Among 3311 students, the prevalence of meningococcal carriage was 3.21%-4.01%. Phenotypically nongroupable strains accounted for 88% of carriage isolates. There were only 5 observed acquisitions of serogroup Y strains during the study; therefore, the impact of MCV4-DT on meningococcal carriage could not be determined.

CONCLUSIONS

Meningococcal carriage rates in US high school students were lower than expected, and the vast majority of strains did not express capsule. These findings may help explain the historically low incidence of meningococcal disease in the United States.

Climate, demographic factors and geographical variations in the incidence of invasive meningococcal disease in Italy

We investigated the effect of climatic, demographic factors and intra-country geographical variations on the incidence of invasive meningococcal disease (IMD) in Italy. For this purpose, incidence rates of IMD cases reported in Italy between 1994 and 2012 were calculated, and a cluster analysis was performed. A geographical gradient was determined, with lower incidence rates in central and southern Italy, compared to the northern parts, where most clusters were observed. IMD rates were higher in medium-sized towns than in villages. Adults were at lower risk of IMD than children aged ⩽4 years. IMD incidence tended to decrease with increasing monthly mean temperatures (incidence rate ratio 0·94, 95% confidence interval 0·90-0·99). In conclusion, geographical variations in IMD incidence were found, where age and temperature were associated with disease occurrence. Whether geographical variations should be considered in national intervention plans is still a matter for discussion.

Association between population prevalence of smoking and incidence of meningococcal disease in Norway, Sweden, Denmark and the Netherlands between 1975 and 2009: a population-based time series analysis

OBJECTIVE

To investigate the relationship between the prevalence of smoking in the population and incidence of invasive meningococcal disease (IMD) among children under 5 years of age.

DESIGN

Retrospective, longitudinal, observational study. Poisson regression controlled for confounding factors.

SETTING

Norway, Sweden, Denmark and the Netherlands between 1975 and 2009.

POPULATION

Total population of approximately 35 million people in these four countries.

DATA SOURCES

Data were collected from the Ministries of Health, National Statistics Bureaus and other relevant national institutes.

RESULTS

In Norway, there was a significant positive relationship between the annual prevalence of daily smokers among individuals aged 25-49 years and the incidence of IMD in children under 5 years of age, unadjusted (RR=1.04-1.06, 95% CI 1.02 to 1.07, p<0.001) and after adjustment for time of year (quarter), incidence of influenza-like illness and household crowding (RR=1.05-1.07, 95% CI 1.03 to 1.09, p<0.001). Depending on age group, the risk of IMD increased by 5.2-6.9% per 1% increase in smoking prevalence among individuals aged 25-49 years in adjusted analyses. Using limited datasets from the three other countries, unadjusted analysis showed positive associations between IMD in children related to older smokers in Sweden and the Netherlands and negative associations related to younger smokers in Sweden. However, there were no demonstrable associations between incidence of IMD and prevalence of smoking, after adjustment for the same confounding variables.

CONCLUSIONS

The reduced incidence of IMD in Norway between 1975 and 2009 may partly be explained by the reduced prevalence of smoking during this period. High-quality surveillance data are required to confirm this in other countries. Strong efforts to reduce smoking in the whole population including targeted campaigns to reduce smoking among adults may have a role to play in the prevention of IMD in children.

Second hand smoke exposure and the risk of invasive meningococcal disease in children: systematic review and meta-analysis

Background

Invasive meningococcal disease remains an important cause of serious morbidity and mortality in children and young people. There is a growing body of literature to suggest that exposure to passive smoke may play a role in the development of the disease, therefore we have performed a systematic review to provide a comprehensive estimate of the magnitude of this effect for smoking by any household member, by individual family members, and of maternal smoking before and after birth.

Methods

Four databases (Medline, Embase, PsychINFO and CAB Abstracts database) were searched to identify studies (to June 2012) and reference lists scanned for further studies. Titles, abstracts and full texts were checked for eligibility independently by two authors. Quality of included studies was assessed using the Newcastle-Ottawa Scale. Pooled odds ratios (OR) with 95% confidence intervals (CI) were estimated using random effect models, with heterogeneity quantified using I².

Results

We identified 18 studies which assessed the effects of SHS on the risk of invasive meningococcal disease in children. SHS in the home doubled the risk of invasive meningococcal disease (OR 2.18, 95% CI 1.63 to 2.92, I² = 72%), with some evidence of an exposure-response gradient. The strongest effect was seen in children under 5 years (OR 2.48, 95% CI 1.51 to 4.09, I² = 47%). Maternal smoking significantly increased the risk of invasive meningococcal disease by 3 times during pregnancy (OR 2.93, 95% CI 1.52-5.66) and by 2 times after birth (OR 2.26, 95% CI 1.54-3.31).

Conclusions

SHS exposure, and particularly passive foetal exposure to maternal smoking during pregnancy, significantly increases the risk of childhood invasive meningococcal disease. It is likely that an extra 630 cases of invasive meningococcal disease annually in children under 16 are directly attributable to SHS exposure in UK homes.

Passive smoking, invasive meningococcal disease and preventive measures: a commentary

Active smoking is a recognized risk factor of various infectious diseases. In a systematic review published in BMC Public Health, Murray et al. demonstrated that exposure to passive smoking significantly increased the risk of meningococcal disease among children. Their review especially highlights that the risk remains high even if the exposure occurs during pregnancy or after birth, although the authors could not disentangle the independent effects of smoking during pregnancy from those in the postnatal period. How passive smoking increases the risk of childhood meningococcal disease is not precisely known. Both exposure to 'smoke', or 'smokers' (who are highly susceptible to pharyngeal carriage of meningococci) are postulated mechanisms, but unfortunately very few studies have examined the risk of exposure by considering these two variables separately, and this therefore remains a research priority. Quitting may well be the mainstay of preventing tobacco-related hazards but the available global data suggest that most smokers are reluctant to quit. Among other interventions, immunizing children with a meningococcal conjugate vaccine could, theoretically, reduce the risk of meningococcal disease among children and their smoker household contacts through herd immunity. See related article http://www.biomedcentral.com/1471-2458/12/1062

Carriage rates and serogroups of Neisseria meningitidis among freshmen in a University dormitory in Korea

PURPOSE

Neisseria meningitidis is a leading cause of bacterial meningitis in young adults. University students, especially those living in dormitories, have been known to be at increased risk of meningococcal disease. We performed a longitudinal study to determine the carriage rates of N. meningitidis and the changes thereof.

MATERIALS AND METHODS

We recruited Inha University freshmen who were, at that time, admitted to a student dormitory. A pharyngeal swab was taken from all participant who were also asked to complete a questionnaire. This was repeated four weeks later.

RESULTS

A total of 136 students were enrolled at the first culture. After four weeks, 128 students were enrolled, including 106 re-participants. The overall carriage rates changed from 11.8% to 14.1%. In analysis of the 106 re-participants, "visiting to pubs" was associated with carriage of N. meningitis for both the first (p=0.047) and second cultures (p=0.026). Serogroup C was found to be the most frequent serogroup (5 isolates), while 3 isolates were found from serogroup B. The most prevalent PorA types were P1.22,14-6 (4 isolates) and P1.19,15 (3 isolates). The DNA sequences of PorA VR2 were changed in 2 students during prolonged carriage.

CONCLUSION

The meningococcal carriage rate among first year university students who resided in a dormitory did not significantly increase over 4-week interval between cultures, which is markedly different from those reported in Western studies. Close social contact appeared to be related with carriage. Our data also revealed diversity in PorA types, suggesting the possibility of rapid mutation of the PorA gene during the 4-week interval.

Smoking and the outcome of infection

Smoking has substantial local and systemic adverse effects on the immune system, respiratory tract and skin and soft tissues. Smokers are at increased risk of invasive pneumococcal disease, pneumonia, periodontitis, surgical infections, tuberculosis, influenza and meningococcal disease. The results of several studies indicate that smokers with periodontitis or tuberculosis suffer more severe disease. Data on the impact of smoking on sepsis and pneumonia are controversial and limited, and systematic data regarding the outcome of the majority of infections in smokers are scarce. Abundant data indicate that children exposed to environmental tobacco smoke (ETS) suffer from more severe infections. However, information regarding the effects of ETS on the outcome of infections in adults is limited. Various aspects of the relation between smoking and the outcome of bacterial infection (e.g. potential dose-dependent effects and the interactions between smoking and other environmental factors that may affect the course of infectious diseases) remain to be established.

Pneumococcal carriage is more common in asthmatic than in non-asthmatic young men

INTRODUCTION

  The aim was to investigate the prevalence of oropharyngeal carriage of Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Neisseria meningitidis and beta-haemolytic streptococci among asthmatic and non-asthmatic young Finnish men and to identify putative risk factors.

OBJECTIVES

  A total of 224 asthmatics and 668 non-asthmatic men (mean age 19.6 years) from two intakes of conscripts to the Kainuu Brigade, Finland in July 2004 and January 2005 were enrolled upon entering military service.

METHODS

  Oropharyngeal specimens were examined for bacteria by routine culture methods. All the participants filled in questionnaires concerning risk factors for asthma and respiratory infections.

RESULTS

  S. pneumoniae (48 cases, 5.4%), Group A streptococci (16, 1.8%), H. influenzae (45, 5.0%), M. catarrhalis (24, 2.7%) and N. meningitidis (20, 2.2%) were isolated from the 892 participants. Ten putative risk factors for oropharyngeal colonization (asthma, atopy, allergic rhinitis, smoking, current use of asthma medication, history of adeno/tonsillectomy, level of highly sensitive C-reactive protein, peak expiratory flow, results of a 12-min running test and body mass index) were evaluated. The only significant risk factor for S. pneumoniae carriage was asthma (OR, 2.04; 95% CI 1.12 to 3.72).

CONCLUSIONS

  Pneumococcal carriage is more common in asthmatic than in non-asthmatic young men.

Association of secondhand smoke exposure with pediatric invasive bacterial disease and bacterial carriage: a systematic review and meta-analysis

BACKGROUND

A number of epidemiologic studies have observed an association between secondhand smoke (SHS) exposure and pediatric invasive bacterial disease (IBD) but the evidence has not been systematically reviewed. We carried out a systematic review and meta-analysis of SHS exposure and two outcomes, IBD and pharyngeal carriage of bacteria, for Neisseria meningitidis (N. meningitidis), Haemophilus influenzae type B (Hib), and Streptococcus pneumoniae (S. pneumoniae).

METHODS AND FINDINGS

Two independent reviewers searched Medline, EMBASE, and selected other databases, and screened articles for inclusion and exclusion criteria. We identified 30 case-control studies on SHS and IBD, and 12 cross-sectional studies on SHS and bacterial carriage. Weighted summary odd ratios (ORs) were calculated for each outcome and for studies with specific design and quality characteristics. Tests for heterogeneity and publication bias were performed. Compared with those unexposed to SHS, summary OR for SHS exposure was 2.02 (95% confidence interval [CI] 1.52-2.69) for invasive meningococcal disease, 1.21 (95% CI 0.69-2.14) for invasive pneumococcal disease, and 1.22 (95% CI 0.93-1.62) for invasive Hib disease. For pharyngeal carriage, summary OR was 1.68 (95% CI, 1.19-2.36) for N. meningitidis, 1.66 (95% CI 1.33-2.07) for S. pneumoniae, and 0.96 (95% CI 0.48-1.95) for Hib. The association between SHS exposure and invasive meningococcal and Hib diseases was consistent regardless of outcome definitions, age groups, study designs, and publication year. The effect estimates were larger in studies among children younger than 6 years of age for all three IBDs, and in studies with the more rigorous laboratory-confirmed diagnosis for invasive meningococcal disease (summary OR 3.24; 95% CI 1.72-6.13).

CONCLUSIONS

When considered together with evidence from direct smoking and biological mechanisms, our systematic review and meta-analysis indicates that SHS exposure may be associated with invasive meningococcal disease. The epidemiologic evidence is currently insufficient to show an association between SHS and invasive Hib disease or pneumococcal disease. Because the burden of IBD is highest in developing countries where SHS is increasing, there is a need for high-quality studies to confirm these results, and for interventions to reduce exposure of children to SHS.

Smoking status interacts with the association between mannose-binding lectin serum levels and gene polymorphism and the carriage of oropharyngeal bacteria

Mannose-binding lectin (MBL) role in the carriage of oropharyngeal bacteria is not known. We investigated the association of smoking, MBL2 polymorphisms, and MBL concentrations with oropharyngeal carriage of respiratory bacteria in young men. Oropharyngeal specimens, MBL concentrations, and MBL2 gene polymorphisms were measured in 124 asthmatic and 394 nonasthmatic Finnish military recruits. The carriage rates of S. pneumoniae (p = 0.002), N. meningitidis (p = 0.005), and beta-hemolytic streptococci (p < 0.001) throughout the military service were significantly higher among smokers than in nonsmokers. An MBL level below the median proved to be a significant risk factor for the carriage of N. meningitidis (odds ratio [OR] = 1.9; 95% confidence interval [CI] 1.0-3.6) and beta-hemolytic streptococci (OR = 2.0; 95% CI 1.2-3.2) in the nonsmokers and a borderline significant risk factor for the carriage of S. pneumoniae (OR = 1.5; 95% CI 0.9-2.6), whereas low MBL levels producing MBL2 haplotypes (LXA/LXA, LXA/O, HYA/O, LYA/O, O/O) seemed to be associated with the carriage of N. meningitidis (OR = 1.8; 95% CI 1.0-3.4) and S. pneumoniae (OR = 1.6; 95% CI 0.9-2.7). Thus, MBL deficiency may predispose nonsmokers to oropharyngeal carriage of these bacteria. We hypothesize that the major factor contributing to elevated bacterial carriage in smokers might be increased bacterial adherence to epithelial cells, which obscures the effect of MBL.

Tobacco use increases susceptibility to bacterial infection

Active smokers and those exposed to secondhand smoke are at increased risk of bacterial infection. Tobacco smoke exposure increases susceptibility to respiratory tract infections, including tuberculosis, pneumonia and Legionnaires disease; bacterial vaginosis and sexually transmitted diseases, such as chlamydia and gonorrhoea; Helicobacter pylori infection; periodontitis; meningitis; otitis media; and post-surgical and nosocomial infections. Tobacco smoke compromises the anti-bacterial function of leukocytes, including neutrophils, monocytes, T cells and B cells, providing a mechanistic explanation for increased infection risk. Further epidemiological, clinical and mechanistic research into this important area is warranted.

Modifiable risk factors for invasive meningococcal disease during an Edmonton, Alberta outbreak, 1999-2002

BACKGROUND

An outbreak of invasive meningococcal disease (IMD) in metro Edmonton, Alberta, Canada between December 1999 and June 2002 resulted in 84 laboratory-confirmed cases. Most cases were infected with Neisseria meningitidis serogroup C, and the highest age-specific incidence was observed in the 15-19 year age group.

METHODS

A case-control study was conducted to identify modifiable IMD risk factors among outbreak cases. Two controls were matched to each case on age and sex, and were recruited through random-digit dialing. A questionnaire was telephone-administered to 132 study participants (44 cases, 88 controls). Conditional logistic regression was utilized to calculate risk measures.

RESULTS

Multivariate analysis revealed three statistically significant risk factors: bar patronage (OR 35.2; 95% CI: 2.64-468), "rave" attendance (OR 12.8; 95% CI: 1.47-111) and maternal smoking (OR 8.88; 95% CI: 1.67-47.4). Humidifier use in the home was protective (OR 0.07; 95% CI: 0.009-0.64).

CONCLUSION

While the precision of risk estimates was low in the multivariate model, this study has identified rave attendance as an emergent IMD risk factor.

Environmental tobacco smoke exposure and respiratory morbidity in children

Environmental tobacco smoke (ETS) contains carcinogenic and toxic agents. Smoking might have a more serious effect on children than adults. We aimed to examine the effects of passive smoking on pulmonary function and respiratory health in children and to assess the concordance between parental self-reported smoking habits and urinary cotinine levels in their children. This cross-sectional study was conducted in the winter with the participation of 131 children (9-12 yr old). The procedure for each subject consisted of administration of a questionnaire to the parents, and collection of a urine sample and measurement of lung function in each child. Cotinine level excreted into urine was analyzed with respect to parental self-reported smoking behavior. Working mothers and mothers with higher level of education tended to smoke more at home (p values, respectively, .002 and .005). There was a statistical difference between the urinary cotinine levels of children when divided into two groups according to their fathers' smoking behavior at home (p = .0001). No statistically significant difference was determined in the mean episodes of respiratory infections treated during the last 12 mo among the groups formed according to daily number of cigarettes smoked by the parents at home (1: not exposed; 2: < 5 cigarettes; 3: 5-10 cigarettes; 4: > 10 cigarettes), or among the groups formed according to urinary cotinine levels (1: < 10 ng/ml; 2: > or =10 ng/ml). No significant difference was demonstrated in any of the respiratory function parameters investigated between the groups considered. The reliability of the declarations of the parents in the estimation of ETS exposure of children was low. Children are unable to remove themselves from ETS exposure. It is better to reduce the percentage of parents who smoke rather than to isolate smokers or increase ventilation.

The development of an evidence-based toolkit to prevent meningococcal disease in college students

This article describes an innovative, evidence-based approach to community healthcare: the creation of toolkits to address health problems. The exemplar used is the development of an evidence-based meningococcal disease prevention toolkit, with action plans for dissemination, implementation, and evaluation, to be used by healthcare providers in developing comprehensive programs on college campuses. Qualitative research methods were used to develop the content. Formative and summative evaluations were conducted. Anticipated outcomes of such toolkits when implemented as designed are provision of evidence-based healthcare, improved health status of individuals, populations, and communities, fewer hospitalizations, and reduction of healthcare costs.

Lessons from meningococcal carriage studies

Neisseria meningitidis, an obligate commensal of humans, normally colonizes the mucosa of the upper respiratory tract without affecting the host, a phenomenon known as carriage. In Europe, as much as 35% of young adults are carriers at a given time. Recent studies using molecular methods for clone identification have demonstrated the extensive genetic diversity of the strains isolated from carriers, in comparison with a limited number of hypervirulent strains associated with invasive disease. Published studies and new data generated through the framework of the EU-MenNet clearly indicated significant differences in pathogenicity between meningococcal clones and in the distribution of multilocus sequence types among isolates from asymptomatic carriers among European countries; simultaneous carriage of more than one meningococcal strain in the throat is rare, but occasionally occurs; and the commensal association of particular clones with a host is a long-term relationship, often lasting several months. Further investigations of the carrier state are warranted to improve our understanding of the epidemiology and pathogenesis of meningococcal disease, as well as to support the introduction and to measure the impact of mass vaccination.

Meningococcal Meningitis Prevention Programs for College Students: A Review of the Literature

BACKGROUND AND PURPOSE

The incidence of meningococcal meningitis in college students is higher than in other populations. College students, especially 1st-year students living in dormitories or residence halls, are among those at highest risk of developing the disease. It is estimated that immunization can prevent up to 83% of cases among adolescents and college students. A review of the literature was undertaken to identify and critique the research-based prevention programs that are focused on college students.

METHOD

An extensive search of the Cochrane Database of systematic reviews, Medline, PubMed, and CINAHL was undertaken. The Journal of American College Health was hand searched, and bibliographies were reviewed for studies not otherwise identified. Four publications met the search criteria. These studies were reviewed and graded for level of evidence.

FINDINGS

One study could not be compared with the other three because of its lack of detail. Of the other three studies, two were descriptive and factors were identified that related to vaccination and nonvaccination in the college student population (both Evidence Grade C). Only one study was described that included an educational intervention, which resulted in increased vaccination rates in a college student population (Evidence Grade B).

CONCLUSIONS AND IMPLICATIONS

The published literature is severely limited in the area of meningococcal meningitis prevention programs in the at-risk college student population. A critical need exists for controlled studies to test the interventions that are most effective in this population as well as broader-based studies to further identify those students at increased risk for the disease as well as for nonvaccination.

Children exposed to environmental smoking have a higher antibiotic consumption

In order to investigate what factors influence antibiotic prescribing, a questionnaire answered by 8700 parents to 4-year-old children in Malmö between 1999 and 2004 was analyzed. 51.3% of the 4-year-old children had been treated with antibiotics. Exposure to environmental smoking, attending day care centers, employment of parents and parents born in Sweden was found to be statistically significant risk factor for antibiotic prescribing. The association between environmental smoking and antibiotic treatment found in this study could be used in information campaigns which might not only lead to a decreased antibiotic prescribing among the children, but also future positive health effects for their parents.

Social behavior and meningococcal carriage in British teenagers

Understanding predisposing factors for meningococcal carriage may identify targets for public health interventions. Before mass vaccination with meningococcal group C conjugate vaccine began in autumn 1999, we took pharyngeal swabs from ≈14,000 UK teenagers and collected information on potential risk factors. Neisseria meningitidis was cultured from 2,319 (16.7%) of 13,919 swabs. In multivariable analysis, attendance at pubs/clubs, intimate kissing, and cigarette smoking were each independently and strongly associated with increased risk for meningococcal carriage (p<0.001). Carriage in those with none of these risk factors was 7.8%, compared to 32.8% in those with all 3. Passive smoking was also linked to higher risk for carriage, but age, sex, social deprivation, home crowding, or school characteristics had little or no effect. Social behavior, rather than age or sex, can explain the higher frequency of meningococcal carriage among teenagers. A ban on smoking in public places may reduce risk for transmission.

The Contribution of Smoking and Exposure to Tobacco Smoke to Streptococcus pneumoniae and Haemophilus influenzae Carriage in Children and Their Mothers

BACKGROUND

Exposure to tobacco smoke is associated with higher risk of Streptococcus pneumoniae and Haemophilus influenzae infection. The aim of this study was to determine the influence of smoking and exposure to tobacco smoke on S. pneumoniae and H. influenzae carriage rates in children and their mothers.

PATIENTS AND METHODS

We performed a cross-sectional surveillance study of nasopharyngeal and oropharyngeal carriage of S. pneumoniae and H. influenzae in 208 children aged <60 months and their mothers. Smoking exposure and medical history were recorded. Carriage rates for children and their mothers in nasopharyngeal and oropharyngeal specimens were analyzed on the basis of smoking exposure.

RESULTS

The S. pneumoniae carriage rate was higher among children exposed to smoking than among nonexposed children (76% vs. 60%; P=.016). Exposed children more frequently carried S. pneumoniae serotypes included in the conjugate 7-valent vaccine, compared with nonexposed children (49% vs. 30% of all S. pneumoniae-positive nasopharyngeal cultures; P=.02). Carriage rates of S. pneumoniae were higher among mothers who smoked than among mothers exposed to smoking and among nonexposed mothers (32%, 15%, and 12%, respectively; P=.03). There were no differences in H. influenzae carriage rates between children and mothers from smoking and nonsmoking families.

CONCLUSIONS

Exposure to tobacco smoke increased S. pneumoniae carriage rates in general and for carriage of serotypes included in the conjugate 7-valent vaccine in particular in children. Smoking mothers had a higher S. pneumoniae carriage rate than did nonsmoking mothers. Smoking or exposure to smoking did not increase H. influenzae carriage rates in children and mothers.

Risk and protective factors for meningococcal disease in adolescents: matched cohort study

OBJECTIVE

To examine biological and social risk factors for meningococcal disease in adolescents.

DESIGN

Prospective, population based, matched cohort study with controls matched for age and sex in 1:1 matching. Controls were sought from the general practitioner.

SETTING

Six contiguous regions of England, which represent some 65% of the country's population.

PARTICIPANTS

15-19 year olds with meningococcal disease recruited at hospital admission in six regions (representing 65% of the population of England) from January 1999 to June 2000, and their matched controls.

METHODS

Blood samples and pernasal and throat swabs were taken from case patients at admission to hospital and from cases and matched controls at interview. Data on potential risk factors were gathered by confidential interview. Data were analysed by using univariate and multivariate conditional logistic regression.

RESULTS

144 case control pairs were recruited (74 male (51%); median age 17.6). 114 cases (79%) were confirmed microbiologically. Significant independent risk factors for meningococcal disease were history of preceding illness (matched odds ratio 2.9, 95% confidence interval 1.4 to 5.9), intimate kissing with multiple partners (3.7, 1.7 to 8.1), being a university student (3.4, 1.2 to 10) and preterm birth (3.7, 1.0 to 13.5). Religious observance (0.09, 0.02 to 0.6) and meningococcal vaccination (0.12, 0.04 to 0.4) were associated with protection.

CONCLUSIONS

Activities and events increasing risk for meningococcal disease in adolescence are different from in childhood. Students are at higher risk. Altering personal behaviours could moderate the risk. However, the development of further effective meningococcal vaccines remains a key public health priority.

Is it exposure to cigarette smoke or to smokers which increases the risk of meningococcal disease in teenagers?

BACKGROUND

Passive smoking appears to increase the risk of meningococcal disease (MD) in adolescents. Whether this effect is attributable to exposure to cigarette smoke or contact with smokers is unknown.

METHODS

We conducted a prospective population-based case-control study with age, sex matched-controls in 1:1 matching. Participants were 15-19 year old with MD recruited at hospital admission in six regions (65% of the population of England) from January 1999 through June 2000, and their matched controls. Data on potential risk factors were gathered by confidential interview, including seven passive smoking variables. Factor analysis was performed to assess the dimensionality of the passive smoking exposure variables. The data were analysed with univariate and multivariate conditional logistic regression.

RESULTS

144 case-control pairs were recruited (51% male; median age 17.6). Factor analysis identified two independent factors representing passive smoking (P < 0.01), one associated with 'exposure to smoke', the other with 'smoker contact'. Only smoker contact was a significant risk factor for MD (OR = 1.8; 95% CI 1.0-3.3; P = 0.05). In multivariate analysis this factor was still associated with MD independently of potential confounders such as active smoker status and household crowding.

CONCLUSION

Contact with smokers is associated with increased risk of MD in adolescents. This is more likely to be due to higher carriage rates in smokers than to exposure to smoke and emphasizes the importance of public health measures to stop smoking. In epidemiological studies that assess risk from passive smoking, exposure to smoke should be differentiated where possible from contact with smokers.

Risk factors for invasive meningococcal disease in southern Queensland, 2000-2001

AIM

The aim of this paper is to describe the risk factors for invasive meningococcal disease (IMD) in southern Queensland.

METHODS

A case control study during the calendar years 2000-2001 was undertaken.

RESULTS

Eighty-four laboratory-confirmed cases of IMD were notified. Four patients died and were excluded from the present study. Sixty-two (78%) eligible cases and 79 controls selected from the same age group and medical practice as cases, were interviewed. Univariate analysis found that IMD was associated with sharing bedrooms with two or more people (odds ratio (OR) 4.3; 95% confidence interval (CI) 1.2-17.0, P = 0.01), any exposure to tobacco smoke (smoker or passive exposure; OR 2.3; 95% CI 1.1-4.8, P = 0.02), passive exposure to tobacco smoke (OR 2.4; 95% CI 1.0-5.6, P = 0.03) and recent upper respiratory tract infection (OR 1.9, 95% CI 0.9-4.1, P = 0.06). Children who were breast-fed were less likely to develop IMD (OR 0.3; 95% CI 0.1-1.1, P = 0.04). Attendance at a childcare centre was not associated with an increased risk of IMD. In multivariate analysis, IMD was associated with children under 6 years of age who shared a bedroom with two or more people (OR 7.4; 95% CI 1.5-36.1, P = 0.01) or who had a primary carer who smoked (OR 9.1; 95% CI 2.1-39.9, P = 0.003).

DISCUSSION

This is the second Australian study that identifies links between risk of IMD and exposure to cigarette smoke. The risk of IMD in young children could be further reduced if primary caregivers did not smoke. This information may contribute a new perspective to antismoking campaigns.

An unusual case of chronic meningitis

BACKGROUND

Chronic meningitis is defined as symptoms and signs of meningeal inflammation and persisting cerebrospinal fluid abnormalities such as elevated protein level and pleocytosis for at least one month.

CASE PRESENTATION

A 62-year-old woman, of unremarkable past medical history, was admitted to hospital for investigation of a four-week history of vomiting, malaise an associated hyponatraemia. She had a low-grade pyrexia with normal inflammatory markers. A CT brain was unremarkable and a contrast MRI brain revealed sub-acute infarction of the right frontal cortex but with no evidence of meningeal enhancement. Due to increasing confusion and patient clinical deterioration a lumbar puncture was performed at 17 days post admission. This revealed gram-negative coccobacilli in the CSF, which was identified as Neisseria meningitidis group B. The patient made a dramatic recovery with high-dose intravenous ceftriaxone antibiotic therapy for meningococcal meningitis.

CONCLUSIONS

1) Chronic bacterial meningitis may present highly atypically, particularly in the older adult. 2) There may be an absent or reduced febrile response, without a rise in inflammatory markers, despite a very unwell patient. 3) Early lumbar puncture is to be encouraged as it is essential to confirm the diagnosis.4) Despite a delayed diagnosis appropriate antibiotic therapy can still lead to a good outcome.

Neisseria meningitidis: an overview of the carriage state

During periods of endemic disease, about 10 % of the general population harbour Neisseria meningitidis in the nasopharynx. Since N. meningitidis is a strict human pathogen and most patients have not been in contact with other cases, asymptomatic carriers are presumably the major source of the pathogenic strains. Most carrier isolates are shown to lack capsule production. The capsule deficient state of meningococcal strains in the nasopharynx may aid evasion of the human immune defence and hence be selected to survive nasopharyngeal colonization. Carriage itself can be an immunizing process resulting in systemic protective antibody responses. Frequent nasopharyngeal colonization with related bacteria like Neisseria lactamica improves natural immunity to meningococci by the formation of cross-reacting antibodies. While most meningococcal strains recovered from patients belong to a limited number of clonal groups worldwide, strains isolated from carriers comprise numerous genotypes, with only a small proportion of the strains representing invasive clones. During the carriage state, co-colonization with other pathogenic and non-pathogenic bacteria may lead to genetic exchange, which may result in the emergence of new meningococcal clones. The high diversity of meningococcal carrier strains, compared with hypervirulent strains, supports the idea that transmissibility, not invasion, is essential in the life cycle of N. meningitidis.

Carriage of Neisseria meningitidis by Greek children: risk factors and strain characteristics

Oropharyngeal swabs were cultured from 554 children aged 2-19 years attending nurseries, primary schools and secondary schools in the central Athens area. A questionnaire was completed to identify risk factors for carriage. Susceptibility to antimicrobial agents was determined by Etest. The genetic relatedness of the strains was examined by pulsed-field gel electrophoresis (PFGE), and isolate serogrouping was performed by slide agglutination. Twenty-two (4%) children were carriers of Neisseria meningitidis; seven isolates belonged to serogroup C, and five to serogroup B. One isolate was resistant to co-trimoxazole, and five showed intermediate resistance to penicillin. DNA analysis of 16 isolates revealed six distinct PFGE patterns. Clusters with indistinguishable PFGE patterns were noted in the same school. More than one serogroup was included in the same clonal group. On multivariate logistic regression analysis, only age > 12 years remained independently associated with the carrier state (odds ratio, 7.96; 95% CI, 2.24-28.33; p < 0.001). Overall, the N. meningitidis carriage rate among Greek schoolchildren increased with age, and the predominant serogroups in the Athens region were groups C and B. These findings may have important implications for future immunisation strategies with conjugate vaccines.

Meningococcal immunology

There is a major need for an effective vaccine against serogroup B disease. The long-term efficacy of the serogroups A, C, Y and W135 conjugate vaccines and the need for booster vaccines has to be determined, as does the effect of changing epidemiology in the United States and worldwide. Control of serogroup A disease in sub-Saharan Africa is a major challenge.

Asymtomatic carriage of Neisseria meningitidis and Neisseria lactamica in relation to Streptococcus pneumoniae and Haemophilus influenzae colonization in healthy children: apropos of 1400 children sampled

Meningococcal disease is one of the most important causes of morbidity and mortality among children in many parts of the world. Main reservoir of carriage and site of meningococcal dissemination appears to be the upper respiratory tract. Colonization of Neisseria meningitidis and lactamica and factors affecting this carriage were determined in a group of healthy children aged 0-10 years. Meningococcus and N. lactamica carriage were detected in 17 (1.23%) and 245 (17.7%) of 1382 subjects, respectively. Number (%) of serogroups for meningococci was 1 (6), 5 (29), 0 (0), 1 (6), 1 (6), and 9 (53) for A, B, C, D, W135, and Y, respectively. Having more than three household members, elementary school attendance, pharyngeal carriage of Streptococcus pneumoniae and Haemophilus influenzae were associated with carriage of meningococci, whereas age less than 24-month was associated with carriage of N. lactamica. There was a reverse carriage rate between N. meningitidis and N. lactamica by age which may suggest a possible protective role of N. lactamica against meningococcal colonization among pre-school children.

Carriers of Neisseria meningitidis in household contacts of meningococcal disease cases in Catalonia (Spain)

A population-based study was carried out in Catalonia (Spain) from May 1998 to April 1999 to determine the prevalence of Neisseria meningitidis strains in meningococcal disease (MD) cases and their contacts, as well as the prevalence of meningococci in close contacts of patients with MD, and risk factors for its carriage. A total of 364 close contacts of 87 patients with MD were studied. Throat samples were collected by hospital staff before rifampicin chemoprophylaxis was begun. For each contact, a questionnaire was completed for sociodemographic and epidemiological data. A total of 61 contacts (an overall prevalence of 16.8%) were carriers of meningococcal strains (40 B, 10 C, 1 Z and 10 non-groupable isolates). This prevalence is two to three times higher than in the general population (5-10%). In 33/61 microbiologically confirmed cases (54%) and in 9/26 probable cases (35%), contacts carrying N. meningitidis were found. In 22/33 confirmed cases with carrier contacts, it was possible to study the phenotype of the carrier and patient strains (sero-group, serotype and serosubtype). In 14 cases (64%), both strains were identical, in four cases, only a minor change was observed, in three cases, some strain (from the case or from his contact) was non-serotypable and non-serosubtypable, and in one case, both isolates were completely different. Bivariate analysis identified five statistically significant risk factors for meningococcal carriage: age (5-9 years old), meningococcal A+C vaccination, severe household overcrowding, social class and heavy active smoking (>20 cigarettes a day). Multivariate analysis revealed that of these five variables, only heavy active smoking remained statistically significant when the other factors were controlled.