[Distribution, serovar affiliation and epidemiologic behavior of Cryptococcus neoformans isolates from ornamental...

Investigations of faeces samples from breeding stocks of companion birds in the federal state of Thuringia revealed a high contamination rate of companion birds with Cryptococcus (Cr.) neoformans var. neoformans. The prevalence of Cr. neoformans var. neoformans correlated with the spectrum of bird species present in the respective breeding units. The causes for that are not clear at the moment. Sensitivity of Cr. neoformans var. neoformans towards alkaline agents was not confirmed and was ruled out as a reason for different tenacity of the yeast in various bird breedings. Differentiation of varieties within Cr. neoformans was possible on the basis of proline assimilation, determination of canavanine resistance, EDTA urease test, as well as Cr. neoformans var. neoformans factor sera and PCR fingerprinting. Serological differentiation of serovars and PCR fingerprinting resulted in subdivision of Cr. neoformans var. neoformans isolates into two groups, which corresponded to serovars A and D. A prevalence of serovar A isolates was found in investigated bird breeding stocks. This also corresponded to the distribution of Cr. neoformans var. neoformans described in literature in humans with cryptococcosis in Germany. Consequently, serovar A or D infections of patients may be connected with their contacts to Cr. neoformans-excreting companion birds.