Diagnosis of invasive pneumococcal infection by PCR amplification of Streptococcus pneumoniae genomic fragments in blood: a multi-centre comparative study

The increasing interest in the prevention of pneumococcal disease by immunisation necessitates improved organism-specific surveillance. This is particularly the case with regard to the contribution of Streptococcus pneumoniae infection to community-acquired pneumonia where blood cultures are often negative and sputum culture results ambiguous. Examination by PCR of blood samples taken at hospital admission offers one possibility for such improvement. The sensitivity, specificity and convenience of three pneumolysin gene PCR assays were compared in a large study, using EDTA blood from 175 patients (95 with proven pneumococcal bacteraemia, 80 with bacteraemia due to other organisms). The assays used were a PCR-enzyme immunoassay, a hybridisation probe assay run on the Roche LightCycler and a hydrolysis probe (TaqMan) assay run on an ABI 7700. Overall samples from only 57% of patients with bacteraemic pneumococcal infection yielded a positive result in at least one assay. Individual sensitivities ranged from 45% (TaqMan/ABI) through 35% (PCR-EIA) to 21% (Hybridisation/LightCycler). Specificity (PCR negative in the 80 control patients) ranged from 97-100%. The TaqMan/ABI assay was run in two centres and concordance between results was 91.4%, discrepancies being associated with very weakly positive samples. Overall, the TaqMan/ABI was the most sensitive and convenient assay; however, this method does not appear to offer any significant improvement over conventional blood cultures and is unlikely to be sufficiently sensitive to confirm a pneumococcal aetiology for non-bacteraemic pneumococcal pneumonia. For the present, therefore, blood culture is the preferred option.

Primary care workshops can reduce and rationalize antibiotic prescribing

We describe a controlled study comparing the effects on primary care prescribing in west Gloucestershire, UK, where antibiotic workshops were offered, with those in east Gloucestershire, where microbiology tutorials were given. The year-on-year changes in quantity and costs of antibiotics dispensed following general practice prescriptions were measured. There was no significant difference in the number of antibiotic items prescribed across the county, but the number of prescriptions for broad-spectrum agents (quinolones, cephalosporins and co-amoxiclav) declined by 15.4% in west Gloucestershire, compared with a 6.5% increase in east Gloucestershire (P: = 0.002). Use of narrow-spectrum antibiotics (penicillin V, trimethoprim and nitrofurantoin), whose use was encouraged, did not change in west Gloucestershire practices, but decreased by 12% in east Gloucestershire practices (P: = 0.003). There was increased use of clarithromycin and azithromycin in both groups of practices. Antibiotic workshops held in the primary care setting can rationalize antibiotic prescribing. This can reduce prescribing costs and selection pressure by broad-spectrum antimicrobial agents and, perhaps, go some way to reducing the development of resistance.

Induction of immunological memory in UK infants by a meningococcal A/C conjugate vaccine

The induction of immunological memory to serogroup A and C polysaccharides in UK infants immunized with three doses of a meningococcal A/C oligosaccharide CRM197 conjugate vaccine was investigated. Forty UK infants vaccinated previously with three doses of a meningococcal A/C oligosaccharide-CRM197 conjugate vaccine at 2, 3 and 4 months of age, were revaccinated at a mean age of 145.6 weeks with either a 10 or 50 microg dose of licensed meningococcal A/C polysaccharide vaccine. Serogroup-specific antibody and serum bactericidal antibody (SBA) responses were measured by enzyme-linked immunosorbent assay and serum bactericidal assays, respectively. Following challenge, anti-serogroup A and C polysaccharide antibody levels rose from pre-booster geometric mean concentrations (GMC) of 3.1 and 2.1 microg/ml respectively to 19.6 and 21.0 microg/ml 1 month post-booster. Serum bactericidal antibody geometric mean titres (GMTs) for serogroups A and C increased 156- and 113-fold from 2.1 and 7.1 pre-booster respectively to 327.4 and 800.7 post-booster. A serogroup A control group of 45 children received a 10 microg dose of licensed meningococcal A/C polysaccharide vaccine (with no prior history of serogroup A vaccination) had serogroup A SBA GMTs of 2.3 pre-vaccination rising to 8 post-vaccination with corresponding GMCs of 0.8 and 10.8 microg/ml. These rises in SBA following serogroup A/C conjugate vaccination are indicative of immunological priming.

Effect of sequence variation in meningococcal PorA outer membrane protein on the effectiveness of a hexavalent PorA outer membrane vesicle vaccine

Though meningococcal serogroup C conjugate vaccines have been introduced into the UK infant immunisation schedule, there is currently no vaccine solution for serogroup B disease. PorA outer membrane protein (OMP) is a potential serogroup B vaccine candidate. A hexavalent PorA outer membrane vesicle (OMV) vaccine has been evaluated in phase I and II trials with promising results. This vaccine contains six different PorA OMPs each representing a different serosubtype. However, considerable sequence variation occurs in the variable regions (VRs) encoding these serosubtypes. By using recombinant P1.5,10 PorA variants we have demonstrated that the killing of this particular serosubtype combination was due mainly to the induction of antibody to the VR2 (P1.10) epitope region, and that after three or four doses of vaccine there was a significant reduction in the killing of variants P1.10a (three doses, p<0.0001; four doses, p = 0.003) and P1.10f (three doses, p<0.0001; four doses, p = 0.002), as compared to responses to the P1.10 strain, when the P1.10 serosubtype was used as the immunogen. Since large numbers of serosubtype variants are known to exist, this finding may have implications for the use of PorA as a meningococcal serogroup B vaccine.

Early management of meningococcal disease

Meningococcal disease is increasing in incidence in many countries, and effective vaccines for serogroup B strains will not be available for at least 5 to 10 years. In the interim, it is attention to principles of good clinical practice, particularly in the early management of the disease, that have the potential to reduce by half the current case fatality rate of approximately 10%. As discussed in this article, those principles include increased awareness, understanding of the disease and its early symptoms by parents and healthcare professionals, and careful attention to the patient before admission and during the hospital stay.

Dynamics of carriage of Neisseria meningitidis in a group of military recruits: subtype stability and specificity of the immune response following colonization

Meningococcal carriage and the immune response to colonization were studied in a group of military recruits undergoing basic training. Subtyping by determination of the class 1 protein sequence clearly differentiated between strains and demonstrated the dynamics of carriage and transmission. Expression of class 1 protein by each strain remained stable during prolonged carriage by different subjects. Following colonization, a marked increase in serum bactericidal response occurred, which was specific for the subtype of the acquired strain and was associated with an increase in reactivity by Western blot to the homologous class 1 protein. Subjects colonized by multiple strains showed evidence of a specific immune response to the class 1 protein of each strain acquired. The subtype specificity of the bactericidal response to meningococci and the stability of expression of the class 1 protein have important implications for the design of vaccines for prevention of serogroup B meningococcal disease.

Invasive pneumococcal infection in South and West England

Variation in the incidence of invasive pneumococcal disease across South and West England, in 1995, was measured through a survey of microbiology laboratories. A 100% response rate was achieved. The incidence by laboratory varied between 5.2 and 20.4 per 100,000 catchment population (P < 0.001). Adjusting for pneumococcal vaccine uptake rate in over 65 year olds, hospital admission rates, blood culture system used and for the age and sex structure of the population, did not account for this variation. When blood culture sampling rates were included in a logistic regression model, the variation between laboratories was much less and of lower statistical significance (P = 0.019). Higher rates of blood culture sampling were associated with a higher incidence of invasive pneumococcal disease. Consistently high sampling should be encouraged because a higher diagnostic rate should result in more selective prescribing of antibiotics, and secondly because improved ascertainment of severe pneumococcal infections is a prerequisite for the evaluation of new pneumococcal conjugate vaccines.

Successful control of Clostridium difficile infection in an elderly care unit through use of a restrictive antibiotic policy

Toxin-producing Clostridium difficile is the commonest bacterial cause of nosocomial diarrhoea and is a well recognized cause of hospital outbreaks in elderly care units. High C. difficile disease rates have been associated with the use of broad-spectrum antibiotics, especially cephalosporins. An outbreak of C. difficile infection in the elderly care unit at Gloucestershire Royal NHS Trust continued despite increased ward cleaning and strict implementation of infection control measures. A restrictive antibiotic policy that would maintain colonization resistance in the gastrointestinal tract was introduced throughout this unit. Patients admitted with suspected infection were prescribed intravenous (i.v.) benzylpenicillin 1.2-1.8 g every 6 h to cover streptococcal infections and i.v. trimethoprim 200 mg twice daily to cover urinary tract pathogens and Haemophilus influenzae. If the patient had septic shock a single iv dose of gentamicin was given (120-180 mg) to cover more resistant gram-negative bacilli. The following were monitored before and after the policy change. The number of cases of C. difficile toxin-positive diarrhoea; cefuroxime and total antibiotic use on the elderly care wards; patient mortality rates; and length of hospital stay: two hundred and fifty-two and 234 patients respectively with a discharge diagnosis of infection were admitted before and after the antibiotic policy change. Mortality rates and length of hospital stay were unchanged. Cefuroxime prescribing and total antibiotic prescribing costs fell by 5150 pounds sterling and 8622 pounds sterling respectively in the 7 month period after the change. Thirty-seven cases of C. difficile diarrhoea occurred in the period before and 16 in the period after the policy change. The incidence of C. difficile diarrhoea and of cefuroxime use has remained low since then. The use of narrow-spectrum antibiotics for hospital treatment of community-acquired infections in the elderly should be encouraged. Outbreaks of C. difficile diarrhoea should be managed with the combined approach of infection control and strict antibiotic policies.

Management of clusters of meningococcal disease. PHIS Meningococcus Working Group and Public Health Medicine Environmental Group

Guidance on the management of clustered cases of meningococcal disease has been revised following a review of the clusters that occurred in England and Wales between 1 April 1995 and 31 March 1996. Public health action is indicated for confirmed and probable cases but not in response to possible cases. The importance of microbiological confirmation is re-emphasised. Intervention is recommended for defined target groups when two or more confirmed or probable cases occur in a preschool group or school within a four week period. We present a framework to assist in the management of clusters of invasive serogroup C infections in larger and less defined communities.

Hepatitis B markers in Gloucestershire firemen

Occupational exposure to blood and body fluids and the prevalence of serological markers of hepatitis B virus (HBV) infection were studied in Gloucestershire firemen to assess the occupational risk of HBV infection. A high compliance was achieved (472/503, 94 per cent). Cumulative occupational exposure to blood or body fluids rose progressively to 68 per cent after 24 years' service. No sera were positive for hepatitis B surface antigen (HBsAg). Six sera were positive for hepatitis B surface antibody (anti-HBs) and were tested for hepatitis B core antibody (anti-HBc). The four subjects who were positive for anti-HBs alone had all received HBV vaccine. Two sera contained both anti-HBs and anti-HBc. Therefore, 2/472 firemen (0.42 per cent) showed evidence of previous HBV infection, a similar proportion to that found in a recent study in UK blood donors (0.49 per cent). Despite considerable exposure to blood and body fluids, an occupational risk of hepatitis B infection was not found in Gloucestershire firemen.

Phylogenetic and epidemiological analysis of Neisseria meningitidis using DNA probes

The genetic relationships between various serotypes and serogroups of meningococcal strains were investigated by restriction fragment-length polymorphism (RFLP) analysis using a number of random DNA probes and a probe containing a truncated copy of the meningococcal insertion sequence IS1106. The data were used to estimate genetic distance between all pairs of strains and to construct phylogenetic trees for meningococcal strains. B15:P1.16R strains isolated from cases of systemic meningococcal disease in two health districts with a high incidence of disease were clonal in contrast to similar strains from cases occurring in other parts of the UK. Strains from these areas, which contain a similar genomic deletion, were found to be derived from two distinct lineages within the B15:P1.16R phylogenetic group. RFLP data demonstrated that present serological typing systems for the meningococcus do not necessarily reflect true genetic relationships.

The lipooligosaccharide immunotype as a virulence determinant in Neisseria meningitidis

We have studied the antigenic (immunotype) and physical characteristics of the lipooligosaccharide (LOS) of epidemiologically related Neisseria meningitidis case (36) and carrier (76) isolates associated with a virulent clone of meningococci (ET-5 complex). LOS immunotypes were determined by dot blotting using immunotype specific monoclonal antibodies and physical characteristics were determined from silver stained SDS-PAGE following proteinase K digestion. The genetic similarity of the different isolates was confirmed by analysis of the restriction fragment length polymorphisms. An association between LOS immunotype expression and invasive disease was found; 97% of case isolates expressed the L3,7,9 immunotype, of which 13% additionally expressed the L1,8,10 determinant. The LOS immunotypes of carrier strains were much more heterogeneous. The predominant immunotype was L1,8,10 (70%) and only 24% expressed L3,7,9 alone. Genotypically related case isolates from Norway (6) and Austria (18) expressed the L3,7,9 immunotype with similar frequency to the U.K. isolates. The combination of LOS immunotype and capsule expression appears to be related to the virulence of these meningococcal strains.

An outbreak of hepatitis A in Gloucester, UK

During an outbreak of hepatitis A that occurred in Gloucester, UK between September 1989 and January 1991, 162 clinical cases were identified through notifications and laboratory reports, a monthly attack rate of 1.05 per 10,000 residents. The highest attack rate was seen in 5-14-year-olds. There were significant correlations between hepatitis A attack rates in the electoral wards of Gloucester and with the Jarman UPA 8 scores for the wards and with overcrowding, unemployment, under 5-year-olds and ethnic minority. The use of human normal immune globulin prophylaxis (HNIG) for household contacts was unsuccessful in ending the outbreak, partly because only one third of cases reported a household contact with recent hepatitis A. Our experience does not support the use of HNIG in stopping community-wide outbreaks of hepatitis A. Two public health campaigns were mounted during the outbreak; both were followed by a fall in the number of cases. Greater priority should be given to the implementation and evaluation of public health campaigns in future community-wide outbreaks of hepatitis A.

Salivary antibody testing in a school outbreak of hepatitis A

During a community-wide outbreak of hepatitis A in Gloucester, UK there was a high attack rate in children attending two city primary schools and a pre-school centre sharing the same site. In September 1990, saliva specimens were collected from 478 (85%) of the 562 children. The prevalence of antibody to hepatitis A virus (anti-HAV), as determined by saliva testing, was 29.6%; highest prevalences were seen in 5-6-year-olds and in children from that area of the city at the centre of the community-wide outbreak. The proportion of immune children with a history of clinical hepatitis varied with age from 1 in 42.7 of under-5-year-olds to 1 in 4.7 of 8-10-year-olds. Six children who received prophylaxis with human normal immune globulin (HNIG) because they were household contacts of cases subsequently became infected. Since there was evidence of transmission outside the school environment it is unlikely that a policy of universal prophylaxis within the schools would have stopped the outbreak. Mass prophylaxis in school outbreaks is only likely to be effective if most transmission is occurring at school and if the target population can be clearly defined. Salivary antibody testing is a simple, practical and acceptable procedure in young children. Salivary antibody surveys in conjunction with vaccination against hepatitis A should provide a cost-effective method for control of future outbreaks.

Identification and characterization of a novel insertion sequence, IS1106, downstream of the porA gene in B15 Neisseria meningitidis

Examination of Neisseria meningitidis strains associated with endemic meningococcal disease demonstrated differences in the number of copies of a repetitive sequence. Characterization of a copy of this repetitive sequence present in B15 strains has revealed the presence of a novel insertion sequence (IS1106) located within a complex repetitive region downstream of the gene for the major surface antigen (porA). IS1106 has a length of 1137 bp and is flanked by 36bp inverted repeats. Two open reading frames (ORF1 and ORF2) are present in opposite strands in codon-codon register with ORF2 entirely located within ORF1. The predicted protein from ORF1 demonstrates homology with the 5A protein of IS5 (Kroger and Hobom, 1982). Strains from two independent outbreaks of B15 meningococcal disease in the UK were found to contain the same genomic deletion removing a copy of IS1106 downstream of the porA gene.

Influenza A and meningococcal disease

There are several anecdotal accounts of the association between outbreaks of influenza and meningococcal disease. The exceptional increase in the number of cases of meningococcal infection 2 weeks after an influenza A outbreak in England and Wales during November and December, 1989, provided an opportunity to investigate the relation between the two events. Patients with meningococcal disease in December, 1989, were more likely than age-matched controls to show serological evidence of recent influenza A infection (odds ratio 3.9, 95% Cl 1.2-13.9). The most likely explanation for the association is immune suppression induced by influenza A, though a lowering of mucosal resistance to meningococcal invasion may also be a factor. Public health authorities should be aware of the association and should be prepared to alert medical practitioners and the public to the increased risk of meningococcal disease when influenza A outbreaks occur.

An outbreak of Legionnaires' disease in Gloucester

Fourteen people living in or near the city of Gloucester fell ill with Legionnaires' disease caused by Legionella pneumophila serogroup (SG) 1 between 27 August and 27 October 1986. Another patient had fallen ill on 30 May. Nine of the 15 were diagnosed retrospectively during a case finding exercise. There were three deaths. Three cases of Pontiac fever were also diagnosed. The source was probably one or more wet cooling towers. Nineteen premises in the city with such towers were identified, and three just outside Gluocester. Samples from 11 of the 22 premises grew Legionella spp.; from nine of these L. pneumophila SG 1 (Pontiac) was isolated. The efficacy of regular addition of biocide in addition to hypochlorite added at the time of disinfection in inhibiting the growth of Legionella spp. was demonstrated. A survey of patients' movements during their likely incubation period showed that there was no single building that all patients had visited, but there were two areas of the city which nearly all had visited or passed through by car. A case-control study demonstrated an association with one of these areas. Cooling towers near both areas may have been sources but the evidence is insufficient to incriminate any single one. The unexpected finding of L. pneumophila SG 1 (Pontiac) in nine towers supports the hypothesis that there may have been multiple sources. Cooling towers may have been contaminated by mains water or by drift from other towers.

Meningococcal carriage in close contacts of cases

Between 1 October 1986 and 31 March 1987, 55 cases of meningococcal disease were identified in the South-West of England, an attack rate of 1.54 per 100,000 during the study period. Antibiotics used in the treatment of the disease successfully eliminated nasopharyngeal carriage of meningococci in 13 out of 14 cases without use of rifampicin. The overall meningococcal carriage rate in 384 close contacts was 18.2% and the carriage rate of strains indistinguishable from the associated case strain was 11.1%. The carriage rate of indistinguishable strains in household contacts (16.0%) was higher than the carriage rate in contacts living at other addresses (7.0%, P less than 0.05). A 2-day course of rifampicin successfully eradicated meningococci from 46 (98%) of 47 colonized contacts. In one third of cases groupable meningococci were isolated from at least one household contact; 92% of these isolates were of the same serogroup as the associated case strain. When a meningococcus is not isolated from a deep site in a clinical case of meningococcal disease, culture of serogroup A or C strains from nasopharyngeal swabs of the case or of household contacts is an indication that the close contact group should be offered meningococcal A + C vaccine in addition to chemoprophylaxis. The failure in this and other studies to isolate meningococci from any household contact in the majority of cases may be due either to the relative insensitivity of nasopharyngeal swabbing in detecting meningococcal carriage or to the acquisition of meningococci by most index cases from sources outside the household.

Identification of a UK outbreak strain of Neisseria meningitidis with a DNA probe

To investigate the epidemiology of meningococcal disease, a specific DNA probe pUS210 (carrying insert DNA which is repeated in the meningococcal genome) was isolated. The ability of this probe to hydridise with multiple polymorphic fragments in Southern blots was exploited to examine genetic relations within strains. Two geographically distinct foci of prolonged meningococcal disease (Gloucester and Plymouth, UK) are due to a clonal population of virulent strains that are distinct from those found elsewhere in the UK.

Congenital rubella after previous maternal immunity

Two mothers who had asymptomatic rubella infection in pregnancy gave birth to severely affected infants. In both, the presence of preexisting antibody was well documented, although it could not be established whether it was the result of vaccine or natural infection.

Effect of smoking on meningococcal carriage

A case-control study was done to examine whether certain environmental or medical factors were associated with meningococcal carriage. Questionnaires were posted to 138 meningococcal carriers and their controls, and to 52 carriers of Neisseria lactamica and their controls. Carriers were matched to controls by age, sex, and area of residence. The overall response rate was 89%. There were no differences in environmental or medical factors between N lactamica carriers and their controls, nor in household crowding, housing conditions, frequency of physical exercise, or upper respiratory disorders between meningococcal carriers and their controls. Active smoking and the presence of other smokers in the household were independently associated with meningococcal carriage; the risk of carriage increased significantly with heavier smoking.

Blood group, secretor status and susceptibility to bacterial meningitis

Epidemiological evidence is summarized for associations of ABO blood group and secretor status with susceptibility to invasive disease due to capsulate organisms responsible for the majority of bacterial meningitis. Host-parasite interactions that might underly these findings are proposed and evidence to support or refute them provided.

The Stonehouse study: secretor status and carriage of Neisseria species

The genetically determined inability to secrete the water-soluble glycoprotein form of the ABO blood group antigens into saliva and other body fluids is a recognized risk factor for meningococcal disease. During a community-wide investigation of a prolonged outbreak of disease due to a B15:P1.16 sulphonamide-resistant strain of Neisseria meningitidis in Stonehouse, Gloucestershire (the Stonehouse survey), the ABO blood group and secretor status of almost 5000 residents was determined. The proportion of non-secretors in the Stonehouse population was significantly higher than the proportion of non-secretors among blood donors in the South West Region and in England generally. Seven of 13 Stonehouse residents with meningococcal disease who were tested were found to be non-secretors, a high proportion. The outbreak in Stonehouse cannot be explained solely in terms of the increased proportion of non-secretors. There was no clear correlation between the proportions of non-secretors in different areas within the town and the incidence of cases of meningococcal disease. Carriers of meningococci, whether outbreak or other strains, were not more likely to be non-secretors. The reasons why non-secretors are more susceptible to meningococcal disease remain to be determined, but they do not appear to be related to carriage of meningococci.

Salmon as a food-poisoning vehicle--two successive Salmonella outbreaks

Gastroenteritis due to Salmonella montevideo occurred amongst guests attending two social functions held within 24 h, food for both having been provided by the same catering firm. Salmon was the most likely vehicle of infection in each case, although cross-contamination of other foods occurred. There were no deaths; four patients were admitted to hospital, one of whom underwent appendicectomy. A review of salmon-associated food-poisoning outbreaks suggests that fresh salmon is an infrequent cause of food poisoning in the United Kingdom. The two outbreaks described here resulted from a failure of simple kitchen hygiene measures at a time of high ambient temperatures. Some current cooking instructions for salmon are inadequate.

An outbreak of meningococcal disease in Stonehouse: planning and execution of a large-scale survey

In November 1986 a large-scale survey was undertaken in the Gloucestershire town of Stonehouse during an outbreak of meningococcal disease due to group B type 15 subtype P1.16 sulphonamide-resistant strains. There were 15 cases in Stonehouse residents during the 4 years from April 1983, an annual attack rate of 56.5 per 100,000. Four secondary cases occurred despite rifampicin prophylaxis. The objectives of this community survey were to investigate patterns of meningococcal carriage, transmission and immunity and to determine the proportion of non-secretors of blood group antigens in the Stonehouse population and amongst meningococcal carriers. A total of 6237 subjects participated including 75% of the 6635 Stonehouse residents. Over 97% of the participants provided all three of the requested specimens-nasopharyngeal swabs, saliva and blood samples. The co-operation between the many organizations involved in the detailed preliminary planning was instrumental in the success of the survey; in particular the value of effective collaboration between Departments of Community Medicine and Microbiology and of the Public Health Laboratory Service network of laboratories in undertaking investigations of this size and type was clearly demonstrated.

The Stonehouse survey: nasopharyngeal carriage of meningococci and Neisseria lactamica

A total of 6234 nasopharyngeal swabs was collected during a survey of the population of Stonehouse, Gloucestershire in November 1986 as part of an investigation into an outbreak of meningococcal disease. The overall meningococcal carriage rate was 10.9%. The carriage rate rose with age from 2.1% in the 0- to 4-year-olds to a peak of 24.5% in the 15- to 19-year-olds, and thereafter declined steadily with age. Male carriers outnumbered female carriers of meningococci by 3:2. Group B (or non-groupable) type 15 sulphonamide-resistant strains which had caused the outbreak were isolated from 1.4% of subjects. The age distribution of carriers of these strains was similar to that of other meningococci apart from an additional peak in the 5-9-year age group and a more rapid decline in carriage with increasing age. Variations in the carriage rates of the outbreak strain were seen in children attending different schools and in the residents of different areas of the town. The low carriage rate of these strains in a community during a prolonged outbreak supports the hypothesis that these organisms are less transmissible but more virulent than other strains of pathogenic meningococci. Carriage of Neisseria lactamica, which is thought to be important in the development of meningococcal immunity, was most frequent in children under the age of 5 years and was six times commoner in this age group than carriage of Neisseria meningitidis. In older children and adults female carriers of N. lactamica increasingly outnumbered males in contrast to the male preponderance observed with meningococcal carriage.

Meningococcal meningitis

Meningococci continue to cause outbreaks of disease throughout the world. The UK is currently experiencing an upsurge due to organisms of groups B and C. There is substantial under-reporting of meningococcal disease, only meningitis currently being notifiable. All significant meningococcal strains should be typed by a reference laboratory. New approaches to vaccine development permit cautious optimism for the future.

An outbreak of meningococcal disease in Gloucestershire

Between October, 1981, and March, 1986, there were 65 cases of meningococcal infection, about five times the expected number, in Gloucester Health District. The cases, mainly in teenagers and young adults, were clustered in the Stroud district and in the southern part of Gloucester City, and most were caused by a sulphonamide-resistant group B type 15 meningococcus. 2 patients died. Only 57% of meningitis cases were formally notified. 7 (11%) patients had septicaemia without meningitis, not a notifiable disease. All meningococcal disease should be made notifiable and meningococci should be serotyped routinely so that the epidemiology of the disease can be monitored before the introduction of suitable vaccines.