Serotype, mating type and ploidy of Cryptococcus neoformans strains isolated from patients in Brazil

Abstract

SUMMARYSerotype, mating type and ploidy of 84 strains of Cryptococcus neoformans isolated from 61 AIDS and 23 non-AIDS patients admitted in a tertiary teaching hospital in São Paulo, Brazil were examined. Among 61 strains isolated from AIDS patients, 60 strains were var. grubii (serotype A). Only one strain was var. gattii (serotype B). No var. neoformans (serotype D) was found. Among 23 strains isolated from non-AIDS patients, 15 were var. grubii (serotype A) and the remaining 8 were var. gattii, all of which were serotype B. Seventy-three of the 75 serotype A strains were the heterothallic α type (MATα) and the remaining 2 were untypable (asexual). Most of the MATα strains (69/73) were haploid and the remaining 4 strains were diploid. Similarly, both of the 2 asexual strains among the 75 serotype A strains were haploid. There were no α-mating type (MATa) strains among the 84 isolates. All of the 8 var. gattii strains were serotype B and haploid. Among a total of 84 strains tested, neither serotype AD nor serotype D were found. Neither triploid nor tetraploid were found. These results suggest that the serological, sexual and ploidy characteristics in C. neoformans strains isolated from AIDS patients in São Paulo were rather simple, whereas strains isolated from non-AIDS patients presented serotype A and B with predominance of serotype A.

Genotyping, serotyping and determination of mating-type of Cryptococcus neoformans clinical isolates from São Paulo State, Brazil

“…Mating type α-specific primer was used here and yielded a 101bp MATα fragment in all cases, showing that all C. neoformans isolates were MATα, consistently with a previous study showing that MATα is more frequent than MATa among clinical as well as environmental isolates 12,25,27,42 . Information about the mating-types of C. neoformans strains is important for an understanding of their ecology and virulence.…”

Six monophyletic lineages identified within Cryptococcus neoformans and Cryptococcus gattii by multi-locus sequence typing

“…All four diploid/aneuploid isolates within the C. neoformans cluster belonged to MATa and possessed one allele for each of the six loci analyzed. Other diploid/aneuploid C. neoformans isolates, which posses only one mating-type allele, have been described (Cogliati et al, 2001;Ohkusu et al, 2002;Litvintseva et al, 2003). The presence of only one mating-type allele and the identification of only one allele for all six studied loci suggest that these isolates may have originated from auto-diploidization or same-sex mating.…”

Molecular characterization and evaluation of virulence factors of Cryptococcus laurentii and Cryptococcus neoformans strains isolated from external hospital areas

“…neoformans and C. gattii are heterothallic and have complementary sexual crossing systems, or mating types (MAT ), with a locus with two alleles: MATa and MATa. It is important to know which sexual type is involved, in order to understand the ecology and virulence of this microorganism (Chaturvedi et al 2000;Lengeler et al 2001;Ohkusu et al 2002).…”