Transport of Neisseria meningitidis cultures: Growth-supporting media and freezing as an alternative

The abilities of Transgrow (TG), Thayer-Martin (TM) and New York City (NYC) solid media to maintain the viability of 12 strains of Neisseria meningitidis under various controlled conditions were assessed. The effects of charcoal impregnation of swabs, temperature, and enriched CO₂ atmosphere were examined with holding for up to 21 days. Recovery from samples held at 35°C was, in almost all instances, greater than at 22 or 4°C. A strong requirement for added CO₂ was demonstrated, especially at lower temperatures. No positive effect could be attributed to the use of charcoal-impregnated swabs. NYC and TM media were the best overall, with the former permitting recovery from more than 75% of all samples held on slants for 20 days at 4°C in an atmosphere of 5% CO₂ in air. Freezing, with holding on dry ice, was a useful alternative to the use of growth-supporting media. This latter method eliminated the requirement for an enriched CO₂ atmosphere.