SUMMARYOne hundred and fourteen cases of pneumococcal meningitis were identified by prospective laboratory based surveillance during 1990-3 in the North East Thames Region. Higher rates of disease were seen in Asians (2' 1 / 100000) than Caucasians (0 8/ 100000) (P = 0 002). The incidence of meningitis was higher in children than adults, while mortality rates were highest in adults over the age of 60 (48 %). In 72 cases, both blood and CSF were culture positive. Serotyping of 65 isolates collected identified 22 serotypes (and one non-typable) causing disease, the most common being serotype 6 (13 cases) and serotype 14 (11 cases). Overall, 90% of serotype antigens identified were represented in the 23 valent vaccine. Ribotyping of 62 isolates identified 35 different patterns, of which 26 were single types. Different ribotypes were found among isolates of the same serotypes, with the exception of serotype 14, where 9 of 11 isolates had the same ribotype pattern. Four percent of isolates had reduced susceptibility to penicillin, but no high level penicillin resistance was found.

Objective-To describe the epidemiology of primary bacterial meningitis in the North East Thames region over a three year period before and during the introduction of the vaccine for Haemophilus influenzae type b.Design-Analysis of information on cases of primary bacterial meningitis identified by microbiology laboratories in the region, with collection of case data by questionnaire. Main outcome measures-Annual incidence rates for types of meningitis according to age and ethnic group.

Summary. Strains of Haemophilus injluenzae type b were collected as part of an epidemiological study of bacterial meningitis in the North East Thames Region (NETR) of England. Subclones of H. injluenzae were identified by outer-membrane protein typing and multilocus enzyme electrophoresis. These were compared with subclones of H. injuenzae type b isolated from elsewhere in the UK. The subclone ET 12.5/OMP 3L was identified in 68 YO of isolates from cases of meningitis from the NETR. In the isolates from elsewhere in the UK, this subclone was identified in 79 O/ O of sterile-site isolates and 91 O/ O of isolates from non-sterile sites. This subclone predominated in patients of different ages and from different ethnic groups, which suggests that non-Caucasians are infected with the subclone predominating locally. Since ET 12.5/OMP 3L subclone is the most abundant strain isolated in virtually all other Western European countries, these results provide additional evidence that the genetic diversity in the H. influenzae type b population in Europe is relatively restricted.