Changing carriage rate of Neisseria meningitidis among university students during the first week of term: cross sectional study

Microbiology

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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