Pharyngeal swabs were taken using cotton swabs and plated immediately onto a selective medium; GC agar (Oxoid) containing vancomycin, colistin, nystatin, and trimethoprim (VCNT selective supplement SR91, Oxoid). The plates were then incubated at 37(C in air with 5% carbon dioxide and examined at 24 and 48 hours. Colonies suggestive of Neisseria spp were tested by the Gonocheck (EY Labs, San Mateo, CA) system according to the manufacturer’s instructions. All colonies reacting as meningococci were sent to the Meningococcal Reference Unit (Manchester Public Health Laboratory) for confirmation, serogrouping, serotyping, and serosubtyping.[1][2][3][4] Any isolate failing to serogroup was further tested for (-glutamyl aminopeptidase activity to confirm its identity as N meningitidis and for lactose fermenting activity by ortho-nitro-phenyl-glucosamine to identify strains of the closely related commensal organism N lactamica.
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Frasch CE, Zollinger WB, Poolman JT. Serotype antigens of Neisseria meningitidis and a proposed scheme for designation of serotypes. Rev Infect Dis 1985;7:504-9.
Wedege E, Hoiby EA, Rosenqvist E, Froholm LO. Serotyping and serosubtyping of Neisseria meningitidis isolates by co-agglutination, dot-blotting and ELISA. J Med Microbiol 1990;31:195-201.
Abdillahi H, Poolman JT. Neisseria meningitidis group B serosubtyping using monoclonal antibodies in whole cell ELISA. Microb Pathogen 1988;4:27-32.