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PubMed1996

[Lethal meningeal encephalitis from Cryptococcus neoformans var. neoformans in a girl without serious immunodeficiency].

Case report on a lethal meningo-encephalitis due to Cryptococcus neoformans in a 14-year-old girl without serious immunodeficiency inclusive HIV-infection. The detection of high quantities of cells of Cryptococcus neoformans (about 10,000/ml) and high levels of Cryptococcus antigen (up to 1:2048) in the cerebrospinal fluid are remarkable. The patient was treated with a triple combination of amphotericin B, flucytosine and fluconazole. After 18 days the cerebrospinal fluid was sterile. Nevertheless considerable lesions of the brain arised. The patient died from the Cryptococcus infection on day 74 of the antimycotic therapy. Cryptococcosis should be included into the differential diagnosis of the chronic lymphocytic pleocytosis of the cerebrospinal fluid connected with symptoms of intracranial pressure and ocular symptoms.

Adolescent↗

PubMed1993

Serotyping of Cryptococcus neoformans by using a monoclonal antibody specific for capsular polysaccharide.

The importance of epidemiological studies of cryptococcosis has increased since the beginning of the AIDS epidemic. Cryptococcus neoformans exists in two varieties defining four serotypes, Cryptococcus neoformans var. neoformans (serotypes A and D) and Cryptococcus neoformans var. gattii (serotypes B and C). The varieties are easy to distinguish by their differences of growth on diagnostic media. We propose here an easy serotyping method combining diagnostic media and a direct immunofluorescence assay with one monoclonal antibody (E1) specific for cryptococcal polysaccharide. The method was validated by the blinded testing of four to five reference strains of each serotype. Immunofluorescence patterns were characteristic of a given serotype provided that the variety of the strain had been defined before. For C. neoformans var. neoformans, a bright, homogeneous staining with several cell aggregates was characteristics of serotype A, whereas only a few serotype D cells were positive. For C. neoformans var. gattii, a completely negative isolate was serotype C, whereas the population of serotype B included a majority of negative cells but also included positive cells with a speckled pattern. The method was then used to serotype 156 clinical isolates from France and isolates from areas where C. neoformans var. gattii was endemic before the AIDS epidemic (13 strains from Rwanda and Zaire and 5 strains from Australia). The specificity of E1 was defined by its reactivity with various Cryptococcus spp. and analyzed according to the described cryptococcal antigenic factors. We conclude from this study that E1 provides a rapid and reliable means to serotype multiple isolates of C. neoformans.

AIDS-Related Opportunistic Infections↗

PubMed2006

Simultaneous detection and identification of Candida, Aspergillus, and Cryptococcus species by reverse line blot hybridization.

We report on a reverse line blot (RLB) assay, utilizing fungal species-specific oligonucleotide probes to hybridize with internal transcribed spacer 2 region sequences amplified using a nested panfungal PCR. Reference and clinical strains of 16 Candida species (116 strains), Cryptococcus neoformans (five strains of Cryptococcus neoformans var. neoformans, five strains of Cryptococcus neoformans var. grubii, and six strains of Cryptococcus gatti), and five Aspergillus species (68 strains) were all correctly identified by the RLB assay. Additional fungal species (16 species and 26 strains) not represented on the assay did not exhibit cross-hybridization with the oligonucleotide probes. In simulated clinical specimens, the sensitivity of the assay for Candida spp. and Aspergillus spp. was 10(0.5) cells/ml and 10(2) conidia/ml, respectively. This assay allows sensitive and specific simultaneous detection and identification of a broad range of fungal pathogens.

Aspergillus↗

PubMed1997

Laccase and melanin in the pathogenesis of Cryptococcus neoformans.

Cryptococcosis, caused by an encapsulated fungus, Cryptococcus neoformans, has emerged as a life threatening infection in HIV positive individuals and other immunocompromised hosts. The present review describes laccase and its product melanin as an important virulence factor of Cryptococcus neoformans and illustrates the approaches used in elucidating the pathogenesis of cryptococcosis. Characterization of the biochemical pathways leading to melanin synthesis is summarized using biochemical and biomolecular approaches. Melanin synthesis is dependent on a single copper-dependent enzyme, laccase. Since the mammalian host does not contain this enzyme, laccase is an attractive candidate for the study of fungal pathogenesis, as well as a drug target. The cloning of the CNLAC1 gene and construction of CNLAC1 gene knock-out strains has confirmed its role in the virulence of Cryptococcus. Also described is the role of melanin in the host-pathogen interactions. Melanin may protect Cryptococcus cells by a variety of methods including anti-oxidant or cell wall surface effects thereby offering protection against numerous effectors of cellular immunity.

Antioxidants↗

PubMed2006

Cutaneous cryptococcus in an elderly woman with chronic essential dermatitis.

Cryptococcus neoformans is a common cause of life-threatening infection. Cutaneous manifestations of Cryptococcus can be primary or secondary, most commonly from immunosuppression. With the global emergence of acquired immunodeficiency syndrome (AIDS), incidence of cryptococcosis is increasing and now represents a major life-threatening fungal infection in these patients. Nonspecific lesions may cause misdiagnosis. Disseminated Cryptocoocus requires early clinical diagnosis and effective management to decrease mortality. We review a case of cutaneous Cryptococcus as a complication of chronic essential dermatitis treated with long-term immunosuppressive agents and discuss updated guidelines on the treatment of Cryptococcus.

Antifungal Agents↗

PubMedDate not supplied

[Association of yeasts of the Cryptococcus genus with Eucalyptus species in Santafé de Bogotá].

Environmental isolation of Cryptococcus neoformans var. gattii was first made in Australia in 1989 by ELLIS. He established a specific association with the tree species Eucalyptus camaldulensis and E. tereticornis. Based on his findings, ELLIS proposed that the fungus could be exported from Australia to others regions, including Colombia, by means of infected seeds. The purpose of this study was to isolate and identify Cryptococcus sp., associated with Eucalyptus trees; this is the first ecological evaluation of C. neoformans var. gattii in our country. A total of 100 Eucalyptus trees, distributed among 13 zones, located in the center, northeast, east and west of Santafé de Bogotá, were studied. Flowers, fruits, leaves, barks and Eucalyptus debris were collected. The samples were processed by extraction with saline solution containing antibiotics, cultured in selective media and the isolates were identified by morphological and biochemical characterístics. Twenty-seven isolates of 9 Cryptococcus sp. were recovered from 21 Eucalyptus trees, from 5 zones. One C. neoformans var. neoformans serotype A was recovered. The Cryptococcus associated with Eucalyptus is important because this is the first study done in our country.

Agglutination Tests↗

PubMed1987

Evaluation of SOC for the presumptive identification of Candida albicans and Cryptococcus neoformans.

SOC, a fungal growth medium composed of Solryth, oxgall, and caffeic acid, was evaluated as a medium to provide rapid, differential identification of Candida albicans and Cryptococcus neoformans. Using a variety of common isolation media to produce the yeast inocula, the germ tube methods tested ranked in the following order of decreasing sensitivity: SOC (97% +/- 1), serum (92% +/- 5), rabbit coagulase plasma with EDTA in combination with tryptic soy broth (89% +/- 5), TOC (89% +/- 6), and rabbit coagulase plasma with EDTA (83% +/- 4). In chlamydospore production, SOC also proved to be the most sensitive after 24 h incubation: SOC (96% +/- 2), TOC (80% +/- 2), and cornmeal-Tween 80 agar (14% +/- 3). Other medically important yeasts showed normal patterns of growth within 24 h on SOC, thus assisting in their identification. Eighty strains of Cryptococcus neoformans showed characteristic brown pigmentation on SOC and TOC within 18 h, while all other species of the genus Cryptococcus and 229 Candida isolates did not show a change in pigmentation.

Candida albicans↗

PubMed1975

Abnormalities in cell-mediated immunity in patients with Cryptococcus neoformans infection.

Cryptococcin, streptokinase-streptodornase (SK-SD), mumps, and purified protein derivative (PPD) were used for skin testing and, with whole killed Cryptococcus neoformans, were used in migration inhibition and lymphocyte transformation assays of control subjects and patients with past or present disseminated C. neoformans infection. Cryptococcin was found to differentiate control subjects grouped by known Cryptococcus exposure. Cryptococcin and C. neoformans were effective in stimulating leukocyte migration inhibition and lymphocyte transformation in the cryptococcin skin test-positive control subjects. Fifteen apparently normal patients who had been cured of cryptococcosis were found, as a group, to have impaired responsiveness to skin testing with cryptococcin and mumps, minimal leukocyte migration inhibition when stimulated with cryptococcin or C. neoformans, but normal group responses to cryptococcin in Cryptococcus-induced lymphocyte transformation. Six patients with known predisposing conditions to disseminated infection (sarcoid, lymphoma, leukemia, steroid therapy) had markedly diminished responses to most skin tests and in vitro assays. It is suggested that the apparently normal individual who develops disseminated cryptococcal infection has subtle defects in cellular immunity that may have antedated and predisposed to infection.

Antigens, Fungal↗

PubMed2005

The PRP8 inteins in Cryptococcus are a source of phylogenetic and epidemiological information.

Only two nuclear encoded inteins have been described. The first, SceVMA, was found in a vacuolar ATPase gene of Saccharomyces cerevisiae and related yeasts. The second, CnePRP8, was found in the PRP8 gene of Cryptococcus neoformans. CnePRP8 contains protein sequences associated with intein splicing but no endonuclease domain. We compared allelic mini-inteins in both varieties of C. neoformans (var. neoformans and var. grubii) and in the related primary pathogen C. gattii to study the evolution of both the mini-intein and the host. We also describe a full-length, endonuclease-containing intein in Cryptococcus laurentii, a moderately distant relation of C. neoformans. We did not detect an intein in the PRP8 gene of other species of Cryptococcus including species closely related to the C. neoformans/C. gattii group. It is therefore probable that the C. neoformans/C. gattii mini-intein was derived from horizontal transfer in which C. laurentii or another intein-containing species was the source.

Amino Acid Sequence↗

PubMed2002

Killing of Caenorhabditis elegans by Cryptococcus neoformans as a model of yeast pathogenesis.

We found that the well-studied nematode Caenorhabditis elegans can use various yeasts, including Cryptococcus laurentii and Cryptococcus kuetzingii, as a sole source of food, producing similar brood sizes compared with growth on its usual laboratory food source Escherichia coli OP50. C. elegans grown on these yeasts had a life span similar to (C. laurentii) or longer than (C. kuetzingii) those fed on E. coli. However, the human pathogenic yeast Cryptococcus neoformans killed C. elegans, and the C. neoformans polysaccharide capsule as well as several C. neoformans genes previously shown to be involved in mammalian virulence were also shown to play a role in C. elegans killing. These included genes associated with signal transduction pathways (GPA1, PKA1, PKR1, and RAS1), laccase production (LAC1), and the alpha mating type. C. neoformans adenine auxotrophs, which are less virulent in mammals, were also less virulent in C. elegans. These results support the model that mammalian pathogenesis of C. neoformans may be a consequence of adaptations that have evolved during the interaction of C. neoformans with environmental predators such as free-living nematodes and amoebae and suggest that C. elegans can be used as a simple model host in which C. neoformans pathogenesis can be readily studied.

Animals↗

PubMed1986

Poorly encapsulated Cryptococcus neoformans from patients with AIDS. I: Preliminary observations.

Ten isolates of Cryptococcus neoformans recovered from individual patients with the acquired immunodeficiency syndrome (AIDS) were studied in conjunction with three other isolates from non-AIDS patients. On primary culture nine out of ten of the AIDS isolates grew as nonmucoid, dry, pasty colonies resembling those produced by "diphtheroids." One isolate formed moist colonies. In contrast, the three non-AIDS Cryptococcus neoformans isolates produced highly mucoid colonies. India ink mounts of primary cultures of the ten AIDS isolates after 48 hours incubation in 5% CO2 showed markedly smaller capsules than the three non-AIDS isolates. India ink preparations of fresh cerebrospinal fluid of two specimens from AIDS patients in which capsule sizes were systematically determined showed a few moderately encapsulated cells dispersed among numerous others that were poorly encapsulated. This observation was confirmed in mucicarmine-stained smears of cerebrospinal fluid. Poorly encapsulated Cryptococcus neoformans seem to be associated with infections in AIDS patients.

Acquired Immunodeficiency Syndrome↗

PubMed1979

Identification of species of Candida, Cryptococcus, and Torulopsis by gas-liquid chromatography.

Gas-liquid chromatography was used to identify species of Candida, Cryptococcus, and Torulopsis by fatty-acid analysis of the whole-cell hydrolysate. Candida albicans characteristically revealed 2-OH C14:0 and C19:0 (chain length:number of double bonds); these were absent in other organisms. Candida curvata was characterized by a ratio of C16:1 to C16:0 of greater than 1.0. Candida guilliermondii contained C10:0, and Candida tropicalis had no C12:0, these features were used for their identification. Cryptococcus was characterized by the absence of C16:1. Torulopsis was characterized by a C16:1 to C16:0 ratio of greater than 10 accompanied by the presence of one unidentified fatty acid. These data suggested that certain Candida, Cryptococcus, and Torulopsis (the clinically important yeast-like organisms) may be identified by gas-liquid chromatography.

Candida↗

PubMed1987

Evaluation of the experimental pathogenicity of some Cryptococcus species in normal and cyclophosphamide-immunodepressed mice.

The pathogenic potential of distinct Cryptococcus species has been evaluated in mice rendered leukopenic by one or two injections of the potent immunosuppressive drug cyclophosphamide (Cy). Pathogenicity assessment included enumeration of viable cryptococcal cells in animal organs and histopathological observations. It was found that putatively non-pathogenic species of Cryptococcus, in particular C. cereanus and C. albidus, showed significant lethality for Cy-treated mice. In Cy-immunodepressed mice, challenged with the infectious cryptococcal cells two days after pharmacological treatment, a significant decrease of LD50 (equivalent to at least one order of magnitude) was observed for all Cryptococcus species. However, the pathogenicity enhancement due to Cy immunodepression was greater with C. neoformans. In all cases, brain and kidney were the most invaded tissues as also evidenced by histopathological examination, which showed the typical cystic lesion. All the observations made point to the conclusion that the pathogenic potential, for the immunomodulated host, of Cryptococci other than C. neoformans is significant being quantitatively and not qualitatively different from that of C. neoformans, as evidenced by a similar organotropism and similar type of histological lesions in the target organs (brain and kidney).

Animals↗

PubMed1974

Medium containing trypan blue and antibiotics for the detection of Cryptococcus neoformans in clinical samples.

A medium containing trypan blue, gentamicin, and chloramphenicol is introduced for the detection of Cryptococcus neoformans and Cryptococcus species from clinical samples. Ten recently isolated strains of Cryptococcus species as well as several clinical isolates of C. neoformans incorporated trypan blue and produced dark blue colonies on this mycological medium, whereas other common yeasts were light blue. The laboratory diagnosis of two cases of cryptococcosis was accomplished by the isolation of C. neoformans on the antibiotic-dye-containing medium. Compared to conventional media supporting large numbers of Pseudomonas aeruginosa and other gram-negative bacilli, the new medium was selective for yeasts. In one instance, the colonization of the respiratory tract by C. neoformans which led to fungemia was traced by the use of the antibiotic-dye medium. The antibiotic mixture, utilized herein, was more effective in suppressing bacteria contained in samples from patients than a medium containing cycloheximide and chloramphenicol.

Candida albicans↗

PubMed1977

Diagnostic medium containing inositol, urea, and caffeic acid for selective growth of Cryptococcus neoformans.

An agar medium containing inositol and urea as sole carbon and nitrogen sources, caffeic acid and ferric citrate as agents for the selective pigmentation of Cryptococcus neoformans, gentamicin as a broad-spectrum bacterial antibiotic, and yeast nitrogen base without amino acids and ammonium sulfate (Difco) was tested against 137 clinical isolates, 4 survey specimens, and 11 ATCC yeast and yeast-like strains. All 28 strains of C. neoformans showed heavy growth and dark brown pigmentation after 36 h. All other tested species of Cryptococcus showed heavy growth after 36 h but only light brown pigmentation after 48 h. No growth was observed in any tested strains of Geotrichum, Pityrosporum, Rhodotorula, Saccharomyces, and Torulopsis. Only the Cryptococcus-like Candida humicola grew of the 8 species and 62 strains of Candida tested. Six of 15 strains of Trichosporon cutaneum and 1 of 2 strains of Trichosporon pullulans showed moderate growth after 48 h. Very different colonial and microscopic morphology and/or the absence of brown pigmentation easily differentiated these strains of T. cutaneum, T. pullulans, and C. humicola from C. neoformans. The growth- and pigmentation-providing characteristics of the medium were unaffected by 2 h of exposure to 254 nm of ultraviolet light.

Agar↗

PubMed2000

[Cryptococcus species--etiological agents of zoonoses or sapronosis?].

Cryptococcus strains are doubtless the cause of a sapronosis which occurs worldwide as cryptococcosis in humans and warm-blooded animals. The etiological agent is Cryptococcus neoformans with the varieties neoformans and gattii. The infection proceeds from environmental sources and not from animals suffering from cryptococcosis. Therefore the designation as zooanthroponosis is not right. There is a correlation between the geographical distribution of the varieties of Cryptococcus neoformans in the environments and the clinical manifestation of cryptococcosis. The reservoir of var. neoformans, serotypes A and D, are worldwide pigeons and pet birds which are frequent healthy carriers. They excrete these yeasts with their excrements. Bird droppings favour the propagation of cryptococci in natural substrates. The cryptococcal infection arises from inhalation of contaminated dust. Variety gattii, serotype B, occurs mainly in tropical and subtropical climates and its environmental niche has been identified in Eucalyptus trees. Var. gattii was detected in the air and in decaying wood debris under the canopies of these trees. Serotype C was isolated once from almond trees in Colombia. Cryptococcoses in men caused by var. gattii are endemic in Australia, California, Brazil and other tropical and subtropical regions. Modern molecular typing procedures are available for studying ecological problems of cryptococci and epidemiological questions of cryptococcosis. Immunosuppressed individuals, especially HIV infected persons and AIDS patients, should avoid contact with pigeons and pet birds.

Animals↗

PubMed2001

A nuclear-encoded intein in the fungal pathogen Cryptococcus neoformans.

We have used comparative sequence analysis to identify an intein-like sequence (protein splicing element) present in Cryptococcus neoformans, a fungal pathogen of humans. The sequence encoding this element is present in the C. neoformans PRP8 gene, as an in-frame insertion relative to the PRP8 genes of other organisms. It contains sequences similar to those of the protein-splicing domains of two previously described yeast inteins (in Saccharomyces cerevisiae and Candida tropicalis), although it lacks any recognizable internal endonuclease domain. The Cryptococcus neoformans intein (Cne PRP8) is only the second to be found in a eukaryote nuclear genome; the previously described yeast inteins occur at the same site in the VMA gene homologues of S. cerevisiae and C. tropicalis. The host gene of the Cryptococcus intein, PRP8, encodes a highly conserved mRNA splicing protein found as part of the spliceosome. The Cne PRP8 intein may be a useful drug target in addressing the cryptococcal infections so prevalent in AIDS patients.

Amino Acid Sequence↗

PubMed1993

Phylogenetic relationships of Cryptococcus neoformans and some related basidiomycetous yeasts determined from partial large subunit rRNA sequences.

The genus Cryptococcus was found to be heterogeneous on the basis of partial rRNA sequences. The human-pathogenic species C. neoformans, comprising 4 serotypes and having Filobasidiella neoformans and F. bacillispora as teleomorphs, was found at a relatively large distance from Filobasidium. Serotypes B and C had identical sequences, while in A and D they were different, with D closer to B and C than to A. Filobasidiella depauperata, which lacks a yeast-like anamorph, clustered with F. neoformans. The genus Filobasidium was clearly separated from Filobasidiella and clustered with C. albidus, C. kuetzingii, C. gastricus, C. lupi, C. vishniaciae, C. bhutanensis, C. aerius, C. terreus and C. ater. The latter may represent the anamorph of Filobasidium elegans. The orange to red species of Cryptococcus, as well as C. aquaticus and C. yarrowii, were found completely unrelated with these taxa, C. macerans being affiliated to Cystofilobasidium capitatum. The genus Trichosporon was found relatively homogeneous; it includes C. humicola, C. curvatus and the filamentous species Hyalodendron lignicola. Cryptococcus flavus and C. dimennae probably belong to the Tremellales, though distances between these species are large. The positions of C. laurentii and C. luteolus remains to be determined.

Base Sequence↗