Bird manure filtrate agar for the formation of the perfect state of Cryptococcus neoformans, Filobasidiella neoformans. A comparative study of the agars prepared from pigeon and canary manure.

An account is given to two pairs of C. neoformans strains on two different bird manure filtrate agars, i.e. pigeon manure filtrate and canary manure filtrate agar. Basidiospore formation was observed in both pairs after 3 d incubation at 26 degrees C on both media. 0.1% biphenyl in pigeon manure filtrate agar showed an inhibitory activity on the formation of the perfect state of the C. neoformans pairs tested. Concentrated pigeon manure filtrate allowed growth of the imperfect, however not of the perfect state of C. neoformans. On canary manure filtrate agar, a brown color effect (BCE) of the colonies of the C. neoformans strains was observed in addition to their formation of the perfect state. Except for a known self-fertile strain no self-fertility could be seen in 40 C. neoformans strains on pigeon manure filtrate agar. Attention is drawn to the risk of laboratory infection when handling the perfect state of C. neoformans.