PCR diagnosis

Nonculture diagnosis is of increasing importance in maximizing case ascertainment of disease owing to Neisseria meningitidis (1). In the United Kingdom (UK), greater use of pre-admission antibiotics has lead to a steady decline in the total number of cases confirmed by culture, compared to the number reported to the Office for National Statistics (ONS). In addition, since the introduction of serogroup C oligosaccharide-protein conjugate vaccine (2) in the UK and its imminent introduction elsewhere, it is necessary to maximize case ascertainment to determine the true level of disease in the population and establish the impact of vaccination programs. Although serodiagnosis is available for confirmation, results are retrospective and often inconclusive (1). Amplification by polymerase chain reaction (PCR) provides a rapid, highly sensitive, and specific method for detecting meningococcal DNA from clinical samples. A number of assays have been described, some of which provide additional information about serological markers such as serogroup, serotype, and serosubtype (3-10). The introduction of PCR at the UK Public Health Laboratory Service (PHLS) Meningococcal Reference Unit (MRU) has resulted in a dramatic increase in the number of confirmed cases of meningococcal disease (11). In 1998 an additional 56% of cases were confirmed by PCR alone compared to those confirmed by culture only.