Isolation of Cryptococcus neoformans from hollows of living trees in the city of Alfenas, MG, Brazil

Immunology of Cryptococcal Infections: Developing a Rational Approach to Patient Therapy

Cryptococcal meningoencephalitis is responsible for upwards of 15% of HIV-related deaths worldwide and is currently the most common cause of non-viral meningitis in the US, affecting both previously healthy and people with immune suppression caused by cancer chemotherapy, transplantation, and biologic therapies. Despite a continued 30-50% attributable mortality, recommended therapeutic strategies have remained largely unchanged since the 1950s. Recent murine models and human studies examining the role of the immune system in both susceptibility to the infection as well as host damage have begun to influence patient care decisions. The Damage Framework Response, originally proposed in 1999, was recently used to discuss dichotomous etiologies of host damage in cryptococcal disease. These include patients suffering microbiological damage with low host immunity (especially those immunosuppressed with HIV) and those having low (live) microbiological burden but high immune-mediated damage (HIV-related immune reconstitution syndrome and non-HIV-related postinfectious inflammatory response syndrome). Cryptococcal disease in previously healthy hosts, albeit rare, has been known for a long time. Immunophenotyping and dendritic cell-T cell signaling studies on cerebral spinal fluid of these rare patients reveal immune capacity for recognition and T-cell activation pathways including increased levels of HLA-DR and CD56. However, despite effective T-cell signals, brain biopsy and autopsy specimens demonstrated an M2 alternative macrophage polarization and poor phagocytosis of fungal cells. These studies expand the paradigm for cryptococcal disease susceptibility to include a prominent role for immune-mediated damage and suggest a need for careful individual consideration of immune activation during therapy of cryptococcal disease in diverse hosts.

First isolation of Cryptococcus neoformans genotype VNI MAT-alpha from wood inside hollow trunks of Hymenaea courbaril

Cryptococcal infection is transmitted by the inhalation of Cryptococcus spp. propagules. Information about the Cryptococcus species inhabiting plants might be clinically relevant due to the epidemiological role of these habitats as possible sources of human infection. The aim of this study was to increase the knowledge about the environmental occurrence of cryptococcosis agents. Hollow tree vegetal debris of nine plant species was sampled quarterly over a 12-month period. Melanized colonies were screened for Cryptococcus neoformans and C. gattii by biochemical tests, followed by URA5-RFLP molecular analysis, M13 fingerprinting assays, and mating-typing with the specific a and α primers. The susceptibility to fluconazole of all of the confirmed species colonies was determined using the AFST-EUCAST broth dilution method. We found that the typical Brazilian flora tree Hymenaea courbaril yielded a high cryptococcal burden (median, 10(2) CFU/g) during the summer, autumn and winter seasons. C. neoformans VNI molecular type MAT alpha was identified in all of the samples. The fingerprinting analyses showed great molecular variability with no correlation with the susceptibility profile to fluconazole (MIC range 4 to ≥64 mg/l). To our knowledge, this study is the first describing the association between C. neoformans and Hymenaea courbaril. These observations extend the known geographic distribution of and substantiate a new urban environmental niche for C. neoformans and also emphasize the genetic diversity of the environmental C. neoformans VNI molecular type isolates.

Cryptococcus: isolamento ambiental e caracterização bioquímica

O gênero Cryptococcus caracteriza-se por ser uma levedura responsável por infecção sistêmica, causada pelas espécies Cryptococcus neoformans e Cryptococcus gattii. O fungo é encontrado em substratos de origem animal e vegetal, e a infecção ocorre com a inalação de basidiósporos ou leveduras desidratadas infectantes presentes no ambiente. O presente trabalho teve por objetivo pesquisar a existência de microfocos de Cryptococcussp.em amostras ambientais da cidade de Araçatuba, São Paulo, com a finalidade de minimizar os riscos de contaminação do homem e dos animais, buscando o conhecimento da ecoepidemiologia do Cryptococcus. Foram colhidas 50 amostras oriundas de ocos e troncos de árvores (Cassiasp., Ficussp., Caesalpinea peltophorides) de 10 locais representativos do perímetro urbano, as quais foram encaminhadas ao Laboratório de Bacteriologia e Micologia da Faculdade de Medicina Veterinária de Araçatuba-Unesp, onde foram processadas e semeadas em placas de Petri contendo ágar semente de Níger e Sabouraud dextrose com clorafenicol e incubadas à temperatura de 30ºC, por um período não inferior a cinco dias. Posteriormente, foram submetidas às provas bioquímicas: produção de urease, termotolerância a 37ºC e quimiotipagem em ágar CGB (L-canavanina-glicina-azul de bromotimol). A análise dos resultados revelaram que 17 (34%) dos cultivos foram positivos para o gênero Cryptococcus, sendo nove (18%) para Cryptococcus gattiie oito (16%) para Cryptococcus neoformans. Outras leveduras correlacionadas, como Rhodotorula sp. e Candida sp., também foram isoladas. Conclui-se que os basidiósporos de Cryptococcusencontram-se dispersos na natureza, constituindo microfocos ambientais, não vinculados necessariamente a um único hospedeiro.

Global Molecular Epidemiology of Cryptococcus neoformans and Cryptococcus gattii: An Atlas of the Molecular Types

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.

Cryptococcus spp isolated from dust microhabitat in Brazilian libraries

BACKGROUND

The Cryptococcus spp is currently composed of encapsulated yeasts of cosmopolitan distribution, including the etiological agents of cryptococcosis. The fungus are found mainly in substrates of animal and plant origin. Human infection occurs through inhalation of spores present in the environment.

METHODS

Eighty-four swab collections were performed on dust found on books in three libraries in the city of Cuiabá, state of Mato Grosso, Brazil. The material was seeded in Sabouraud agar and then observed for characteristics compatible with colonies with a creamy to mucous aspect; the material was then isolated in birdseed (Niger) agar and cultivated at a temperature of 37°C for 5 to 7 days. Identification of isolated colonies was performed by microscopic observation in fresh preparations dyed with India ink, additional tests performed on CGB (L-canavanine glycine bromothymol blue), urea broth, and carbohydrate assimilation tests (auxanogram).

RESULTS

Of the 84 samples collected from book dust, 18 (21.4%) were positive for Cryptococcus spp totalizing 41 UFC's. The most frequently isolated species was C. gattii 15 (36.6%); followed by C. terreus, 12 (29.3%); C. luteolus 4 (9.8%); C. neoformans, and C. uniguttulatus 3 (7.3%), and C. albidus and C. humiculus with 2 (4.6%) of the isolates.

CONCLUSION

The high biodiversity of the yeasts of the Cryptococcus genus, isolated from different environmental sources in urban areas of Brazil suggests the possibility of individuals whose immune systems have been compromised or even healthy individuals coming into sources of fungal propagules on a daily bases throughout their lives. This study demonstrates the acquisition possible of cryptococcosis infection from dust in libraries.

The expanding host tree species spectrum of Cryptococcus gattii and Cryptococcus neoformans and their isolations from surrounding soil in India

This study reports the widespread prevalence of Cryptococcus neoformans and Cryptococcus gattii in decayed wood inside trunk hollows of 14 species representing 12 families of trees and from soil near the base of various host trees from Delhi and several places in the Indian states of Uttar Pradesh, Haryana, Tamil Nadu and Chandigarh Union Territory. Of the 311 trees from which samples were obtained, 64 (20.5%) were found to contain strains of the C. neoformans species complex. The number of trees positive for C. neoformans var grubii (serotypeA) was 51 (16.3%), for C. gattii (serotype B) 24 (7.7%) and for both C. neoformans and C. gattii 11 (3.5%). The overall prevalence of C. neoformans species complex in decayed wood samples was 19.9% (111/556). There was no obvious correlation between the prevalence of these two yeast species and the species of host trees. The data on prevalence of C. gattii (24%) and C. neoformans (26%) in soil around the base of some host trees indicated that soil is another important ecologic niche for these two Cryptococcus species in India. Among our sampled tree species, eight and six were recorded for the first time as hosts for C. neoformans var grubii and C. gattii, respectively. A longitudinal surveillance of 8 host tree species over 0.7 to 2.5 years indicated long term colonization of Polyalthia longifolia, Mimusops elengi and Manilkara hexandra trees by C. gattii and/or C. neoformans. The mating type was determined for 153 of the isolates, including 98 strains of serotype A and 55 of serotype B and all proved to be mating type alpha (MAT alpha). Our observations document the rapidly expanding spectrum of host tree species for C. gattii and C. neoformans and indicate that decayed woods of many tree species are potentially suitable ecological niches for both pathogens.

Long-distance dispersal and recombination in environmental populations of Cryptococcus neoformans var. grubii from India

The basidiomycete yeast Cryptococcus neoformans is a cause of significant morbidity and mortality in immunocompromised hosts throughout the world. The sporadic nature of the infection and the limited empirical evidence for direct human-to-human transmission have led to the belief that infections in humans are predominantly caused by the inhalation of basidiospores from environmental sources. Therefore, analysing the structure of environmental populations of C. neoformans can significantly increase our understanding of its ecology, evolution and epidemiology. Decaying wood is a rich source of organic and inorganic compounds and is known to be a suitable ecological niche for many micro-organisms, including C. neoformans. However, relatively little is known about the population structure of C. neoformans sampled from decaying wood. In this study, we analysed samples of C. neoformans var. grubii colonizing decaying wood in tree hollows of nine tree species in five geographical locations (Delhi, Bulandshahar, Hathras, Amritsar and Amrouli) in north-western India. Multilocus sequence typing was conducted using five gene fragments for each of 78 isolates. All isolates belonged to mating type alpha. Population-genetic analyses identified no evidence for significant differentiation among populations belonging to either different geographical areas or different host tree species. Interestingly, despite the lack of mating type a strains in our survey, we found unambiguous evidence for recombination in our population analyses. Our results are consistent with the hypothesis of long-distance dispersal and recombination in environmental populations of this species in India.