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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: 4.23). 06/2000; 38(5):1974-6.
Source: PubMed

ABSTRACT 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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    • "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.
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    • "It was associated with longer hospital stays, significant sequelae, and prolonged therapy, and necessitated additional antifungal treatment (2.4 gm vs. 1.4 gm), compared with those infected with the (n) variety (Mitchell et al., 1995; Speed and Dunt, 1995). The (gr) variety recently was distinguished as a separate strain from the (n) variety based on biochemical properties, and it usually infects patients with AIDS or other immunocompromised states (Steenbergen & Casadevall, 2000). The (g) variety spreads primarily through exposure to several varieties of tropical plants and the bark and leaves of gum trees. "
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    ABSTRACT: Meningitis, when caused by the fungal mycoses Cryptococcus neoformans, is normally seen in immuno-compromised hosts. However, immunocompetent patients are also susceptible to cryptococcal meningitis (CM). In patients with an intact immune system, CM usually presents with the typical signs and symptoms of meningitis: fever, stiff neck, and headache. Major implications for the primary and advanced practice nursing plans of care for CM patients include a thorough history and physical exam, early diagnosis and treatment, and an individualized plan of care focused on minimizing sequelae and side effects of treatment and maximizing functional recovery.
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    • "Furthermore, it has been recently reported that the prevalence of C.n. var. neoformans (serotype D) is signi¢cantly higher than previously perceived [1]. In contrast , the distribution of human cryptococcosis due to C.n. var. "
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    ABSTRACT: Sequences of the internal transcribed spacer (ITS) region including the 5.8S rRNA gene delineated seven genotypes within the three varieties of Cryptococcus neoformans via specific combinations of eight nucleotide differences located at positions 10, 11, 15, 19, 108 (ITS1), 221 (5.8S), 298 and 346 (ITS2). The ITS types correlated to polymerase chain reaction fingerprint/random amplification of polymorphic DNA (RAPD) molecular types: with ITS type 1 (ATACTAGC)=C. neoformans var. grubii, molecular types VNI+VNII and the serotype A allele of the AD hybrid, VNIIIA; ITS type 2 (ATATAGGC)=the serotype D allele of the AD hybrid, VNIIIB, and C. neoformans var. neoformans, VNIV; and ITS type 3 (GCGCTGGC) and ITS type 7 (ACGCTGGC)=VGI=RAPD type III, ITS type 4 (ACACTGAC)=VGII=RAPD type II, ITS type 5: (ACACTGGG)=VGIII=RAPD type I, ITS type 6 (ACACTGGC)=VGIV=RAPD type IV, all corresponding to C. neoformans var. gattii. Cloned sequences from serotype AD revealed that the hybrid serotype is diploid at the ITS1-5.8S-ITS2 locus carrying the ITS type 1 (ATACTAGC) and the ITS type 2 (ATATAGGC) alleles. ITS sequencing is a useful technique for genotyping the three C. neoformans varieties and for subtyping within C. neoformans var. gattii.
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