1887

Abstract

A case of disseminated cryptococcosis caused by var. is presented in a male diabetic who had AIDS. The diagnosis was based upon the isolation and identification of the aetiological agent from a lymph-node biopsy, cerebrospinal fluid and sputum. The isolate formed spherical, encapsulated yeast cells, produced cherry-brown colonies on niger-seed agar, grew on canavanine-glycine-bromothymol blue (CGB) medium, changing its colour from greenish yellow to blue, and hydrolysed urea weakly in the presence of 100 μM EDTA. The strain was unable to assimilate -proline and, serologically, it was untypable. The identity of the isolate as var. , serotype A, possessing a mating-type allele Aα, was confirmed by crossing with standard laboratory test strains and by performing PCR with the mating-type α allele-specific primer of the gene and with serotype (A and D)- and mating type (a and α)-specific primers of the gene. To the best of our knowledge, this is the first report of disseminated cryptococcosis in an AIDS patient caused by a canavanine-resistant strain of var. , serotype A, possessing mating type allele Aα; the strain is probably a hybrid. The report suggests that, in the absence of a clear-cut serotyping result, a positive CGB reaction alone is not sufficient for intervarietal discrimination and additional confirmatory evidence is required.

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2003-03-01
2019-10-20
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