Improved methods of detection of meningococcal DNA from oropharyngeal swabs from cases and contacts of meningococcal disease.

In the UK the increasing use of pre-admission parenteral antibiotic therapy in meningococcal disease has lessened the value of routine cultures as a tool to confirm diagnosis, and laboratory confirmation of invasive meningococcal infection is achieved increasingly by non-culture, nucleic acid amplification methods. The purpose of this study was to evaluate a DNA extraction and meningococcal-specific DNA amplification methodology for detection of meningococci from oropharyngeal swabs. One hundred and six swabs from suspected or confirmed cases of meningococcal disease, and 94 swabs from contacts of meningococcal disease cases were examined. Of laboratory-confirmed cases, 38/65 (58.5%) yielded a positive oropharyngeal swab PCR result and 5/24 (20.8%) swabs from suspected but laboratory-unconfirmed cases were PCR positive. No significant differences in PCR positivity rates were found between the types of swab transport systems utilized, but transport time to the testing laboratory was found to affect PCR positivity (P < 0.05). Application of meningococcus-specific PCR to oropharyngeal swabs, in addition to routine culture of swabs, can provide valuable epidemiological information as well as case confirmation for contact management. PCR amplification of meningococcal PCR from oropharyngeal swabs will also increase the ascertainment in swabbing surveys carried out as part of meningococcal disease outbreak investigation and management.