First isolation of Cryptococcus neoformans var. gattii from a native jungle tree in the Brazilian Amazon rainforest.
TL;DR: The presence of this variety in a virgin environment without either anthropic action or introduced vegetation is discussed with regard to the common knowledge of Cr.
Abstract: Cryptococcus neoformans var. gattii was isolated for the first time from decaying wood in a hollow of a native jungle tree Guettarda acreana, in a wild area of an Amazon rainforest island, in Brazil. The presence of this variety in a virgin environment without either anthropic action or introduced vegetation is discussed with regard to the common knowledge of Cr. neoformans ecology.
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TL;DR: MALDI-TOF mass spectrometry readily distinguishes the newly recognized species, which differ in aspects of pathogenicity, prevalence for patient groups, as well as biochemical and physiological aspects, such as susceptibility to antifungals.
543 citations
TL;DR: Application of recent insights into the life cycle of C. neoformans and its different ways of engaging in sexual reproduction under laboratory conditions has just begun to affect research on the ecology and epidemiology of this human pathogenic fungus.
Abstract: Cryptococcus neoformans is a major cause of fungal meningoencephalitis in immunocompromised patients. Despite recent advances in the genetics and molecular biology of C. neoformans, and improved techniques for molecular epidemiology, aspects of the ecology, population structure, and mode of reproduction of this environmental pathogen remain to be established. Application of recent insights into the life cycle of C. neoformans and its different ways of engaging in sexual reproduction under laboratory conditions has just begun to affect research on the ecology and epidemiology of this human pathogenic fungus. The melding of these disparate disciplines should yield rich dividends in our understanding of the evolution of microbial pathogens, providing insights relevant to diagnosis, treatment, and prevention.
392 citations
TL;DR: Preliminary evidence suggests that C. gattii VGII causes severe lung disease and death without dissemination, whereas C. neoformans disseminates readily to the central nervous system (CNS) and causes death from meningoencephalitis.
Abstract: Understanding of the taxonomy and phylogeny of Cryptococcus gattii has been advanced by modern molecular techniques. C. gattii probably diverged from Cryptococcus neoformans between 16 million and 160 million years ago, depending on the dating methods applied, and maintains diversity by recombining in nature. South America is the likely source of the virulent C. gattii VGII molecular types that have emerged in North America. C. gattii shares major virulence determinants with C. neoformans, although genomic and transcriptomic studies revealed that despite similar genomes, the VGIIa and VGIIb subtypes employ very different transcriptional circuits and manifest differences in virulence phenotypes. Preliminary evidence suggests that C. gattii VGII causes severe lung disease and death without dissemination, whereas C. neoformans disseminates readily to the central nervous system (CNS) and causes death from meningoencephalitis. Overall, currently available data indicate that the C. gattii VGI, VGII, and VGIII molecular types more commonly affect nonimmunocompromised hosts, in contrast to VGIV. New, rapid, cheap diagnostic tests and imaging modalities are assisting early diagnosis and enabling better outcomes of cerebral cryptococcosis. Complications of CNS infection include increased intracranial pressure, severe neurological sequelae, and development of immune reconstitution syndrome, although the mortality rate is low. C. gattii VGII isolates may exhibit higher fluconazole MICs than other genotypes. Optimal therapeutic regimens are yet to be determined; in most cases, initial therapy with amphotericin B and 5-flucytosine is recommended.
298 citations
09 Jan 2013
TL;DR: All the information available in the literature concerning the isolation of the two Cryptococcus species has been collected and analyzed on the basis of their geographical origin, source of isolation, level of identification, species, and molecular type.
Abstract: Cryptococcosis is a fungal disease affecting more than one million people per year worldwide. The main etiological agents of cryptococcosis are the two sibling species Cryptococcus neoformans and Cryptococcus gattii that present numerous differences in geographical distribution, ecological niches, epidemiology, pathobiology, clinical presentation and molecular characters. Genotyping of the two Cryptococcus species at subspecies level supplies relevant information to understand how this fungus has spread worldwide, the nature of its population structure, and how it evolved to be a deadly pathogen. At present, nine major molecular types have been recognized: VNI, VNII, VNB, VNIII, and VNIV among C. neoformans isolates, and VGI, VGII, VGIII, and VGIV among C. gattii isolates. In this paper all the information available in the literature concerning the isolation of the two Cryptococcus species has been collected and analyzed on the basis of their geographical origin, source of isolation, level of identification, species, and molecular type. A detailed analysis of the geographical distribution of the major molecular types in each continent has been described and represented on thematic maps. This study represents a useful tool to start new epidemiological surveys on the basis of the present knowledge.
257 citations
TL;DR: Few among the millions of fungal species fulfill four basic conditions necessary to infect humans: high temperature tolerance, ability to invade the human host, lysis and absorption of human tissue, and resistance to the human immune system.
Abstract: Few among the millions of fungal species fulfill four basic conditions necessary to infect humans: high temperature tolerance, ability to invade the human host, lysis and absorption of human tissue, and resistance to the human immune system. In previously healthy individuals, invasive fungal disease is rare because animals' sophisticated immune systems evolved in constant response to fungal challenges. In contrast, fungal diseases occur frequently in immunocompromised patients. Paradoxically, successes of modern medicine have put increasing numbers of patients at risk for invasive fungal infections. Uncontrolled HIV infection additionally makes millions vulnerable to lethal fungal diseases. A concerted scientific and social effort is needed to meet these challenges.
240 citations
Cites background from "First isolation of Cryptococcus neo..."
...…1990; Fortes et al. 2001; Kidd et al. 2003); although it was first found on Eucalyptus trees and believed to follow their worldwide distribution (Ellis and Pfeiffer 1990), its isolation from the midst of pristine Amazon rainforest revises the interpretation of its origin (Fortes et al. 2001)....
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...…and more recently in temperate regions, particularly from sites of wood decay and insect consumption of vegetable matter (Ellis and Pfeiffer 1990; Fortes et al. 2001; Kidd et al. 2003); although it was first found on Eucalyptus trees and believed to follow their worldwide distribution (Ellis and…...
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References
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TL;DR: A simple new agar medium containing L-canavanine, glycine, and bromthymol blue was found to give a clearer and more accurate distinction between serotype A or D and serotype B or C (C. neoformans var. gattii) than creatinine-dextrose-bromthyl blue or glycine-cycloheximide-phenol red media.
Abstract: A simple new agar medium containing L-canavanine, glycine, and bromthymol blue was found to give a clearer and more accurate distinction between serotype A or D (Cryptococcus neoformans var. neoformans) and serotype B or C (C. neoformans var. gattii) than creatinine-dextrose-bromthymol blue or glycine-cycloheximide-phenol red media. Among 143 isolates of serotype A or D and 70 isolates of serotype B or C, the new medium correlated completely with the serotype, whereas nearly 11% of these isolates gave discrepant reactions with creatinine-dextrose-bromthymol blue and glycine-cycloheximide-phenol red media.
525 citations
TL;DR: Findings may provided an explanation for the high incidence of infections caused by C. neoformans var.
Abstract: Environmental isolations have established that Cryptococcus neoformans var. gattii appears to have a specific ecological association with Eucalyptus camaldulensis. So far, we have isolated C. neoformans var. gattii on 35 separate occasions, all from samples associated with E. camaldulensis. The global distribution of E. camaldulensis appears to correspond to the epidemiologic distribution of cryptococcosis caused by C. neoformans var. gattii. No other environmental source for the fungus has yet been detected, and no other eucalypt has the distribution pattern corresponding to reported cases caused by this fungus. These findings may provided an explanation for the high incidence of infections caused by C. neoformans var. gattii in Australian aborigines living in the Northern Territory and for its low worldwide incidence in acquired immunodeficiency syndrome patients.
525 citations
TL;DR: C. neoformans and C. gattii were found sharing the same natural biotope, thus establishing a possible link between them in their life cycle in nature and suggesting the primary natural niche for the species.
Abstract: To study hollows of living trees as natural habitats of Cryptococcus neoformans in an endemic area of cryptococcosis in the northeastern region of Brazil, samples of decaying wood were collected inside 32 hollows of living trees and plated on niger seed agar. Identification of C. neoformans was based upon morphological and physiological tests. Canavanine-glycine-bromothymol medium was used to screen the varieties and Crypto Check Iatron Kit to serotype the isolates. A total of 123 C. neoformans colonies were recovered from samples of six (18.5%) out of 32 hollow trees. C. neoformans var. neoformans and C. neoformans var. gattii were found occurring alone (pink shower tree, fig tree and pottery tree) or sharing the same hollow (pink shower tree). Long lasting positivity (19-36 months) and significant number of cfu of C. neoformans per gram of decaying wood (0.15-21.7 x 10(3) cfu g(-1)) inside hollows of pink shower tree, fig tree and pottery tree were observed, indicating colonization of these habitats by the fungus. For the first time, C. n. var. neoformans and C. n. var. gattii were found sharing the same natural biotope, thus establishing a possible link between them in their life cycle in nature and suggesting the primary natural niche for the species.
188 citations
TL;DR: As an extension of the previously established association between Cryptococcus neoformans var.
Abstract: As an extension of the previously established association between Cryptococcus neoformans var. gattii and Eucalyptus camaldulensis (River red gum) we have now found a similar relationship between C. neoformans var. gattii and the closely related Eucalyptus tereticornis (Forest red gum). The global distribution of E. tereticornis is similar to that of E. camaldulensis.
183 citations
TL;DR: C. neoformans was repeatedly isolated from decaying wood forming hollows in living trees growing in urban areas of Rio de Janeiro, Brazil, finding a new natural habitat for C. neoforms that is not associated with specific trees.
Abstract: Cryptococcus neoformans var. neoformans was repeatedly isolated from decaying wood forming hollows in living trees growing in urban areas of Rio de Janeiro, Brazil. A new natural habitat for C. neoformans var. neoformans has been found that is not associated with specific trees.
166 citations