• L Ragunathan, M Ramsay, R Borrow, M Guiver, S Gray, and E B Kaczmarski.
• Meningococcal Reference Unit, Withington Hospital, Manchester, UK.
• J. Infect. 2000 Jan 1;40(1):74-9.

ObjectivesTo describe the epidemiological, clinical and laboratory features of meningococcal meningitis and the effects of antibiotics on laboratory investigations under current clinical practices in England and Wales.MethodsUsing a telephone questionnaire, information was gathered on 103 cases with a clinical diagnosis of meningococcal meningitis. Included were cases with samples submitted to the Public Health Laboratory Service (PHLS), Meningococcal Reference Unit (MRU) over a 5-month period in 1997. Tests included microscopic examination, latex agglutination and culture for Neisseria meningitidis, and at MRU confirmation of identification and characterization of isolates and meningococcal polymerase chain reaction (PCR) analysis on blood and cerebrospinal fluids (CSF).ResultsClinically 45% of the cases had predominantly meningitis and 55% had septicaemia and meningitis. Only 29% of the cases received pre-admission benzylpenicillin, and 66% were given antibiotics within an hour of hospital attendance. Microbiological confirmation was achieved in 97 cases, 46 (44%) by traditional tests and 92 (89%) by PCR assay, including some with both. The blood culture positive rate was 23 (22%), but in predominant meningitis the rate was only 10% (5/46). PCR was the sole method of confirmation in 48 cases. Seventy percent of the plasma samples referred were reactive by PCR assay, but all samples taken more than 24 h after hospital antibiotics were non-reactive. PCR-based techniques increased the overall number of cases with a serogroup identified by 44%. Lumbar punctures were performed in 73 of the cases and microbiological confirmation was achieved in 67 (92%) of these cases, compared to 26/30 without lumbar puncture (LP). Eighty-nine percent of the CSF samples referred were reactive by PCR; 50% of the CSF samples taken more than 24 h after hospital antibiotics were reactive, whilst none were positive by culture or microscopy.ConclusionDue to variable clinical manifestations, early diagnosis and treatment was difficult. Laboratory confirmation has been improved by the introduction of PCR-based techniques. Meningococcal DNA was detected by molecular methods in CSF samples taken up to 72 h after commencement of antibiotics. During this period patients could be stabilized and the chances of complications attendant upon early LP reduced. In addition to providing accurate epidemiological information, confirming the diagnosis may alter the extent and length of follow-up.

35 keywords...

hide…