Prevalence of Cryptococcus neoformans var. neoformans (Serotype D) and Cryptococcus neoformans var. grubii (Serotype A) Isolates in New York City

Departments of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
Journal of Clinical Microbiology (Impact Factor: 3.99). 06/2000; 38(5):1974-6.
Source: PubMed


Analysis of 40 New York City Cryptococcus neoformans isolates revealed that 39 were typeable, of which 85 and 12.5% were Cryptococcus neoformans var. grubii (serotype A) and Cryptococcus neoformans var. neoformans (serotype D), respectively. The prevalence of serotype D isolates in New York City appears to be significantly higher than indicated by previous studies of North American isolates.

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    • "Innumerable yeast species and filamentous fungi members are present in the same natural niches of Cryptococcus spp. (Steenbergen and Casadevall, 2000). The search for environmental isolates of Cryptococcus is not new, and recovering the cryptococcal colonies is a difficult task. "
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    ABSTRACT: The isolation of Cryptococcosis agents from environmental samples may be difficult due to the presence of groups of fast-growing fungi. We propose a new culture medium based on a modification of Dichloran Rose-Bengal Chloramphenicol Medium (DRBCm) to detect colonies of Cryptococcus neoformans. Our results indicate that DRBCm is superior to the classical Bird Seed Agar in its ability to detect colonies of C. neoformans.
    Full-text · Article · Aug 2015
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    • "C. neoformans var. grubii (Serotype A) is the predominant disease-causing variety worldwide and accounts for about 95% of cryptococcal infections [8,9]. The nuclear genome of C. neoformans var. "
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    ABSTRACT: Cryptococcus neoformans, a basidiomycetous fungus of universal occurrence, is a significant opportunistic human pathogen causing meningitis. Owing to an increase in the number of immunosuppressed individuals along with emergence of drug-resistant strains, C. neoformans is gaining importance as a pathogen. Although, whole genome sequencing of three varieties of C. neoformans has been completed recently, no global proteomic studies have yet been reported. We performed a comprehensive proteomic analysis of C. neoformans var. grubii (Serotype A), which is the most virulent variety, in order to provide protein-level evidence for computationally predicted gene models and to refine the existing annotations. We confirmed the protein-coding potential of 3,674 genes from a total of 6,980 predicted protein-coding genes. We also identified 4 novel genes and corrected 104 predicted gene models. In addition, our studies led to the correction of translational start site, splice junctions and reading frame used for translation in a number of proteins. Finally, we validated a subset of our novel findings by RT-PCR and sequencing. Proteogenomic investigation described here facilitated the validation and refinement of computationally derived gene models in the intron-rich genome of C. neoformans, an important fungal pathogen in humans.
    Full-text · Article · Feb 2014 · Clinical Proteomics
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    • "Up to 12% of infections in New York City may be caused by var. neoformans (Steenbergen and Casadevall 2000). In Europe, clinical var. "
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    ABSTRACT: The availability of the whole-genome sequence from the 2 known varieties of the human pathogenic fungus Cryptococcus neoformans provides an opportunity to study the relative contribution of divergence and introgression during the process of speciation in a genetically tractable organism. At the genomic level, these varieties are nearly completely syntenic, share approximately 85-90% nucleotide identity, and are believed to have diverged approximately 18 MYA. Via a comparative genomic approach, we identified a 14-gene region (approximately 40 kb) that is nearly identical between the 2 varieties that resulted from a nonreciprocal transfer event from var. grubii to var. neoformans approximately 2 MYA. The majority of clinical and environmental var. neoformans strains from around the world contain this sequence obtained from var. grubii. This introgression event likely occurred via an incomplete intervarietal sexual cycle, creating a hybrid intermediate where mobile elements common to both lineages mediated the exchange. The subsequent duplication in laboratory strains of a fragment of this same genomic region supports evolutionary theories that instabilities in subtelomeric regions promote adaptive evolution through gene amplification and subsequent adaptation. Along with a more ancient predicted transfer event in C. neoformans and a recently reported example from Saccharomyces cerevisiae, these data indicate that DNA exchange between closely related sympatric varieties or species may be a recurrent theme in the evolution of fungal species. It further suggests that although evolutionary divergence is the primary force driving speciation, rare introgression events also play a potentially important role.
    Preview · Article · Nov 2006 · Molecular Biology and Evolution
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