Abstract
Background: The clinical diagnosis of meningococcal disease (MCD) can be difficult. Non-culture methods like the previous ELISA meningococcal PCR improved case confirmation rates, but were not ideal. A Taqman meningococcal PCR, using DNA extracted from serum (S-Taqman), which has an improved sensitivity compared to the ELISA method in vitro, was introduced into clinical practice in July 1997. A new whole blood DNA extraction method for Taqman (WB-Taqman) was introduced in September 1999.
Aims: To determine the degree of improvement in the confirmation rate in clinically diagnosed MCD, following the introduction of WB-Taqman.
Methods: A total of 192 patients (WB-Taqman) with possible or probable MCD, including those admitted to our paediatric intensive care unit, were studied. Admission EDTA samples obtained were sent for bacterial DNA detection at the Meningococcal Reference Unit (MRU), Manchester. These patients were compared to 319 patients with possible and probable MCD, seen at the same hospital prior to the introduction of WB-Taqman.
Results: Following the introduction of WB-Taqman, 82 of the 95 probable cases (88%) had a positive meningococcal PCR result. This gives a diagnostic sensitivity and specificity for WB-Taqman of 87% and 100% respectively. Following WB-Taqman all blood culture positive patients were also PCR positive. Confirmation of cases by PCR rose from 47% (S-Taqman, n = 166) to 88% (WB-Taqman). When all confirmatory tests were included, case confirmation increased from 72% (S-Taqman) to 94% (WB-Taqman).
Conclusion: The sensitivity of PCR in confirming clinical MCD has improved significantly with this new method. The gold standard for confirming cases of MCD is now the WB-Taqman PCR.
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Selected References
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- Carrol E. D., Thomson A. P., Shears P., Gray S. J., Kaczmarski E. B., Hart C. A. Performance characteristics of the polymerase chain reaction assay to confirm clinical meningococcal disease. Arch Dis Child. 2000 Sep;83(3):271–273. doi: 10.1136/adc.83.3.271. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cartwright K. A., Stuart J. M., Jones D. M., Noah N. D. The Stonehouse survey: nasopharyngeal carriage of meningococci and Neisseria lactamica. Epidemiol Infect. 1987 Dec;99(3):591–601. doi: 10.1017/s0950268800066449. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Corless C. E., Guiver M., Borrow R., Edwards-Jones V., Fox A. J., Kaczmarski E. B. Simultaneous detection of Neisseria meningitidis, Haemophilus influenzae, and Streptococcus pneumoniae in suspected cases of meningitis and septicemia using real-time PCR. J Clin Microbiol. 2001 Apr;39(4):1553–1558. doi: 10.1128/JCM.39.4.1553-1558.2001. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Guiver M., Borrow R., Marsh J., Gray S. J., Kaczmarski E. B., Howells D., Boseley P., Fox A. J. Evaluation of the Applied Biosystems automated Taqman polymerase chain reaction system for the detection of meningococcal DNA. FEMS Immunol Med Microbiol. 2000 Jun;28(2):173–179. doi: 10.1111/j.1574-695X.2000.tb01473.x. [DOI] [PubMed] [Google Scholar]
- Marzouk O., Thomson A. P., Sills J. A., Hart C. A., Harris F. Features and outcome in meningococcal disease presenting with maculopapular rash. Arch Dis Child. 1991 Apr;66(4):485–487. doi: 10.1136/adc.66.4.485. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sim R. J., Harrison M. M., Moxon E. R., Tang C. M. Underestimation of meningococci in tonsillar tissue by nasopharyngeal swabbing. Lancet. 2000 Nov 11;356(9242):1653–1654. doi: 10.1016/s0140-6736(00)03162-7. [DOI] [PubMed] [Google Scholar]