Prophylaxis of bacterial meningitis

Longer-duration uses of tetracyclines and penicillins in U.S. food-producing animals: Indications and microbiologic effects

We review and analyze regulatory categories for longer duration of use (defined as ≥ 7 day) tetracyclines (TCs) and penicillins (PNs) approved for U.S. livestock and poultry, together with scientific studies, surveillance programs and risk assessments pertaining to antimicrobial resistance. Indications listed on a government database were grouped into three broad categories according to the terminology used to describe their use: disease control (C), treatment (T) and growth improvement (G). Consistent with mostly therapeutic uses, the majority (86%) of listed indications had C and/or T terms. Several studies showed interruption of early disease stages in animals and modulation of intestinal microflora. Longer-duration exposures are consistent with bacteriostatic modes of action, where adequate exposure time as well as concentration is needed for sufficient antimicrobial activity. Other effects identified included reduced animal pathogen prevalence, toxin formation, inflammation, environmental impacts, improved animal health, reproductive measures, nutrient utilization, and others. Several animal studies have shown a limited, dose-proportionate, selective increase in resistance prevalence among commensal animal bacteria following longer-duration exposures. Pathogen surveillance programs showed overall stable or declining resistance trends among sentinel bacteria. Quantitative, microbiologically detailed resistance risk assessments indicate small probabilities of human treatment failure due to resistance under current conditions. Evaluations of longer-duration uses of TCs, PNs, and other antimicrobial classes used in food-producing animals should consider mechanisms of activity, known individual- and population-level health and waste reduction effects in addition to resistance risks.

Safety and preliminary immunogenicity of MenC/P64k, a meningococcal serogroup C conjugate vaccine with a new recombinant carrier

This study reports the preliminary assessment of the safety and immunogenicity of the first serogroup C conjugate vaccine candidate that includes meningococcal P64k recombinant protein as the carrier (MenC/P64k). Twenty volunteers were recruited for a double-blind, randomized, controlled phase I clinical trial, receiving a single dose of MenC/P64k (study group) and a single dose of the commercial polysaccharide vaccine AC (control group). Only mild reactions were observed. No statistical differences were detected between the antipolysaccharide C IgG responses of both groups as well as between bactericidal serum titre (P > 0.05). The MenC/P64k vaccine was found to have a good safety profile, to be well tolerated and immunogenic.

Risk factors for mortality in Paraguayan children with pneumococcal bacterial meningitis

BACKGROUND

Over the last decade Streptococcus pneumoniae has emerged as the most common bacterial pathogen for meningitis in all age groups, beyond the neonatal period.

OBJECTIVE

To determine the epidemiological and clinical characteristics; and risk factors for mortality of pneumoccocal meningitis in children in a developing transitional country.

MATERIALS AND METHODS

A retrospective study that included patients<15 years of age admitted at the Instituto de Medicina Tropical of Paraguay, from January 1990 until December 2003 with the diagnosis of bacterial meningitis caused by S. pneumoniae. Clinical and laboratory data were collected and analysed in order to identify risk factors associated with morbidity and mortality outcomes of this infection.

RESULTS

Seventy-two patients (between the ages of 35 days and 14 years) were identified. Forty-two per cent of patients had seizures prior to or at the time of admission, 36% were admitted in a comatose state, and 19% with shock. Mortality was 33% (24/72), and 18% of the survivors (11/60) developed severe sequelae. Upon admission, the following variables were strongly correlated with mortality: age<12 months (P=0.007), the presence of seizures (P=0.0001) or development of seizures 48 h after admission (P=0.01), a cerebrospinal fluid (CSF) glucose level of <10 mg/dl (P=0.01), CSF albumin>200 mg/dl (P=0.0003), an absolute blood neutrophil count<2000/mm3 (P=0.006) and a haemoglobin value of <9 g/dl (P=0.0001).

CONCLUSIONS

This study confirms the high morbidity and mortality associated with S. pneumoniae meningitis in Paraguay. Certain clinical parameters and laboratory findings in blood and CSF at the time of admission could be used as predictors for mortality or severe sequelae among survivors.

Bacterial meningitis in children and adolescents: an observational study based on the national surveillance system

Background

Bacterial meningitis is a group of life threatening infections that mostly affect children and adolescents, and may be the cause of severe neurological sequelae. Cuba has implemented massive vaccination programmes against both Neisseria meningitidis (serogroup C in 1979 and B in 1987), and Haemophilus influenzae type b (1999), two of the main causal pathogens. We described and discussed some epidemiological aspects of the current status of bacterial meningitis to learn from the Cuban experience.

Methods

A nationwide observational study on children and adolescents from 1 to 18 years old was carried out from 1998 to 2003, estimating the incidence and case-fatality rate by age group and causal pathogens, as well as the seasonality and frequency of overcrowded dormitories. The association between disease and attendance to day care centres or boarding schools was estimated by using relative risk (Chi-squared test and Fisher Exact Test).

Results

The overall number of cases was 1023; the incidence ranged from 3.4 to 8.5 per 100 000 population, with the higher figures in children 1–5 years old (16.8 per 100 000 population). Streptococcus pneumoniae, Haemophilus influenzae type b and Neisseria meningitidis serogroup B were the main identified agents. The average case-fatality rate was 10.5% and the most lethal agents were Streptococcus pneumoniae (27%) and Haemophilus influenzae type b (10.7%). Overall percentage of cases who slept in overcrowded dormitories was 15%, reaching 30.6% in adolescents. Seasonality was only evident among meningococcal meningitis cases between September–October. The attendance to boarding high school showed an association with disease only in 1998 and 1999 (RR = 2.1; p > 0.05).

Conclusion

The highest incidence of bacterial meningitis was observed among children from 1–5 years old. Pneumococcus was both the leading causal and the most lethal agent. Sleeping in overcrowded dormitories was more frequent among adolescents. No strong association was observed between the bacterial meningitis and attendance to day care centres or boarding schools. The incidence of bacterial meningitis in Cuba is declining after massive vaccination programmes against Neisseria meningitidis serogroup B and C and Haemophilus influenzae type b through a national immunisation program.

Bacterial meningitis in children

This review comprises aspects of the epidemiology, microbiology, pathophysiology, clinical manifestations, diagnosis, management, prognosis, and prevention of bacterial meningitis, with emphasis on the paediatric population. The beginning of this millennium has witnessed the virtual disappearance of Haemophilus invasive disease in some countries, emergence of pneumococcal strains that are resistant to multiple antibiotics, isolation of pneumococci with tolerance to vancomycin, outbreaks and clusters of meningococcal meningitis in several geographical areas, and intense research in development of effective conjugate pneumococcal and meningococcal vaccines. Bacterial meningitis has become an uncommon disease in the developed world. Unfortunately, because of limited economic resources and poor living conditions, many developing countries are still affected by the devastating consequences of this life-threatening systemic infection. Basic and clinical research is needed to discover new antimicrobial and anti-inflammatory agents to improve outcome from disease. Novel strategies are needed to distribute and implement effective vaccines worldwide to prevent bacterial meningitis.

Meningococcal vaccines: a progress report

Neisseria meningitidis causes a wide range of human disease and remains a common cause of septicaemia and meningitis. Meningococcal serogroups A, B, C and Y cause the majority of cases of invasive disease in the US and throughout the world, with epidemics usually caused by serogroups A and C. Most patients with meningococcaemia, with or without meningitis, respond to standard antimicrobial therapy with either penicillin or ampicillin, but the recent emergence of meningococcal strains that are intermediately resistant to penicillin may alter these recommendations in the future. Given the devastating nature of meningococcal disease and emergence of these resistant strains, prevention (specifically through vaccination) remains the best approach to control this serious infection. A polysaccharide meningococcal vaccine is efficacious against disease caused by serogroups A, C, Y and W135, but is not effective in infants and children aged <2 years, and the duration of efficacy decreases markedly during the first 3 years after a single dose of the vaccine. Conjugate meningococcal vaccines have been developed to address these concerns. Initial studies with the meningococcal C conjugate vaccine have shown that the vaccine is safe and immunogenic and provides a T cell-dependent antigen that can be boosted by further doses of vaccine, or following exposure to the homologous organism or cross-reacting antigens. The UK recently implemented routine vaccination with the meningococcal C conjugate vaccine to all infants, and to all persons aged >1 year in a catch-up programme to immunise all school-aged children and young adults up to 20 years of age. Early postlicensure data indicate that this vaccine has shown significant efficacy in reduction of invasive meningococcal disease in these age groups. The full impact of vaccination will be determined once all age groups are immunised.

The effect of subcapsular meningococcal B + C vaccine on the prognosis of patients with meningococcal disease

The effectiveness of the meningococcal Cuban vaccine (VaMengoc B + C) was examined in terms of the prognosis of patients who develop disease. All cases in the vaccinee age category admitted to the Meningococcal Disease Reference Centre, Rio de Janeiro between August 1990 and December 1993 were enrolled. Vaccine effectiveness (VE) was estimated from the relationship 1-OR, where the OR (odds ratio) was the exponential of the logistic regression coefficient for the association between death from meningococcal disease and previous vaccination. The case fatality rate for vaccinees was 6.1% and that for non-vaccinees was 10.6% (relative risk 0.58; 95% confidence interval [CI] 0.33-1.01). An overall protective effect of the vaccine against a fatal outcome was identified (VE 53%; 95% CI 12-75%) controlling for sex, age at time of immunization, elapsed time since vaccination and time between onset of disease and hospital admission. This study suggests that, for some people, even if the vaccine does not protect against the development of disease it may have a beneficial effect in terms of preventing a fatal outcome. This protective effect needs to be further investigated in a prospective cohort study specifically designed to evaluate the new generation of meningococcal vaccines.

New therapies and vaccines for bacterial meningitis

Acute bacterial meningitis remains an important cause of morbidity and mortality worldwide. There have recently been major advances in the prevention of the major causes of bacterial meningitis following improvements in vaccinology. The success of immunisation against Haemophilus influenzae type b infection is being mirrored with serogroup C conjugated meningococcal vaccine and pneumococcal conjugate vaccine. However, there remain major challenges, notably, serogroup B meningococcal infection and shifts in epidemiology caused by vaccine introduction. In addition, much of the world's population is unvaccinated. Therefore, improvements in management of acute bacterial meningitis are vital. In this review we attempt to summarise important advances in both prevention and treatment of acute bacterial meningitis.

Aspectos clínicos e laboratoriais de meningite piogênica em lactentes

OBJETIVO: descrever as características clínicas e laboratoriais da meningite piogênica em lactentes. MÉTODO: informações obtidas a partir do acompanhamento prospectivo dos lactentes com meningite piogênica, admitidos no Hospital Couto Maia no período de março a dezembro de 1997, foram inseridas em um banco de dados e analisadas com auxílio de programas estatísticos. RESULTADOS: meningite piogênica foi mais prevalente em lactentes com idade entre 6 meses e 1 ano, sendo o agente etiológico mais freqüente o Haemophilus influenzae. A letalidade global foi de 25,9% e, entre os sobreviventes, 39,3% deixaram o hospital apresentando alguma anormalidade compatível com envolvimento encefálico ao exame neurológico. CONCLUSÃO: meningite piogênica em lactentes se constitui em enfermidade com taxa de letalidade elevada, sendo, na maioria dos casos, passível de prevenção. Consideramos de grande relevância a adoção de medidas profiláticas de saúde visando redução da incidência desta enfermidade.

Meningococcal disease and travel

Invasive meningococcal disease, in both endemic and epidemic forms, is the cause of significant morbidity and mortality worldwide. Despite all advances in therapy, the fatality rate of meningococcal meningitis remains unacceptably high, between 5% and 10%, and a similar proportion suffers long-term neurological sequalae. Prevention of this rapidly fatal disease is of paramount importance. The use of the available internationally licensed meningococcal vaccines would be indicated for individuals with medical conditions that increase the risk of the disease and for travelers to high-risk countries. In the last 2 years, there has been a shift in the epidemic pattern of meningococcal disease during the Hajj (pilgrimage) season, with predominance of Neisseria meningitidis serogroup W135. Recent changes have been made in the policy issued by the Saudi Ministry of Health (Riyadh, Saudi Arabia), which requires visitors from all over the world arriving for purposes of umra and Hajj to show evidence of vaccination against meningitis with the quadrivalent meningococcal vaccine.