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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↗
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↗
PubMed1992

In vitro responses of cheetah mononuclear cells to feline herpesvirus-1 and Cryptococcus neoformans.

In vitro T cell function by domestic cats and cheetahs to two common pathogens, feline herpesvirus-1 (FHV-1) and Cryptococcus neoformans, was assessed. Peripheral blood mononuclear cells (PBM) were stimulated with two strains of UV-inactivated FHV-1, whole heat-killed organisms or capsular antigen of Cryptococcus neoformans, and proliferative responses measured. As a group, cheetah PBM responded significantly poorer than domestic cat PBM when cultured with FHV-1. However, individual cheetah responses varied widely. Supplementation of cultures with exogenous interleukin 2 (IL-2) significantly increased the level of response of individual cheetahs to both strains of FHV-1. Cheetah sera contained slightly higher neutralizing antibody titers to FHV-1 than did domestic cat sera, suggesting that B cells function adequately in cheetahs. When stimulated with Cryptococcus neoformans, both species had similar incidences of positive proliferative responses. These data demonstrate that cheetahs exhibit heterogeneous responses to specific antigens, similar to domestic cats. However, a lower group response to FHV-1 in cheetahs suggests species differences occur. In addition, level of variability in major histocompatibility complex (MHC) class I-like genes, as determined by Southern blot hybridization, does not appear to correlate with a uniform response in in vitro functional assays. Therefore, additional mechanisms influence the final outcome of the immune response.

Acinonyx↗
PubMed2025

The complex evolution and genomic dynamics of mating-type loci in Cryptococcus and Kwoniella.

Sexual reproduction in basidiomycete fungi is governed by MAT loci (P/R and HD), which exhibit remarkable evolutionary plasticity, characterized by expansions, rearrangements, and gene losses often associated with mating system transitions. The sister genera Cryptococcus and Kwoniella provide a powerful framework for studying MAT loci evolution owing to their diverse reproductive strategies and distinct architectures, spanning bipolar and tetrapolar systems with either linked or unlinked MAT loci. Building on recent comparative genomic analyses, we generated additional chromosome-level assemblies, uncovering distinct trajectories shaping MAT loci organization. Contrasting with the small-scale expansions and gene acquisitions observed in Kwoniella, our analyses revealed independent expansions of the P/R locus in tetrapolar Cryptococcus, possibly driven by pheromone gene duplications. Notably, these expansions coincided with a pronounced GC-content reduction best explained by reduced GC-biased gene conversion following recombination suppression, rather than relaxed codon usage selection. Diverse modes of MAT locus linkage were also identified, including three previously unrecognized transitions: one resulting in a pseudobipolar arrangement and two leading to bipolarity. All three transitions involved translocations. In the pseudobipolar configuration, the P/R and HD loci remained on the same chromosome but genetically unlinked, whereas the bipolar transitions additionally featured rearrangements that fused the two loci into a nonrecombining region. Mating assays confirmed a sexual cycle in Cryptococcus decagattii, demonstrating its ability to undergo mating and sporulation. Progeny analysis in Kwoniella mangrovensis revealed substantial ploidy variation and aneuploidy, likely stemming from haploid-diploid mating, yet evidence of recombination and loss of heterozygosity indicates that meiotic exchange occurs despite irregular chromosome segregation. Our findings underscore the importance of continued diversity sampling and provide further evidence for convergent evolution of fused MAT loci in basidiomycetes, offering new insights into the genetic and chromosomal changes driving reproductive transitions.

Genes, Mating Type, Fungal↗
PubMed1976

[Relations within genus Cryptococcus (Sanfelice) Vuillemin].

A collection of 49 Cryptococcus strains was studied by means of 62 tests, which emphasized morphological, physiological and biochemical properties. The experimental results were subjected to computer analysis using matching coefficient and taxanomic distance. Cluster analysis were carried out using average linkage method. Two clusters and one individual strain were formed, the first cluster represented the genus Cryptococcus, the second cluster and the individual strain did not belong to this genus. The cluster of the genus Cryptococcus was divided into five phenons: Laurentii Neoformans, Albidus, Terreus and Aerius. The belonging of strains to these phenons is discussed comparing the results with those of GC% content in DNA, of the production of coenzyme Q and many other. The quick identification phenons was suggested.

Alcohols↗
PubMed1990

Reactivity of Cryptococcus neoformans & Candida species with concanavalin A & blood grouping sera.

Forty strains of Cryptococcus neoformans, 30 of Candida albicans, 24 of C. parapsilosis and 10 strains each of C. tropicalis and C. (Torulopsis) glabrata were examined. A 0.2 per cent solution of concanavalin A (Con A) in phosphate buffered saline and commercial anti-A and anti-B blood grouping sera were used in the whole cell slide agglutination test. All the isolates of Candida species strongly reacted with Con A and over 90 per cent were agglutinated by anti-A and -B blood grouping sera. In contrast, except for one strain, Cryptococcus neoformans did not agglutinate with Con A or blood grouping sera. These findings suggest, on one hand, a fundamental difference in the sugar mosaic of the cell surface components of Cryptococcus neoformans and Candida species, and on the other, presence of similar antigenic determinant(s)/receptors on the cell surface of Candida species and human erythrocytes.

Agglutination Tests↗
PubMed1989

Isolation of Cryptococcus albidus var. albidus in patient with pemphigus foliaceus.

Cryptococcus albidus var. albidus was isolated from the blood of a patient with pemphigus foliaceus after steroid therapy. This organism was found in triple extract peptone medium which is used in our laboratory for blood culture to detect aerobic and anaerobic bacteria. Identification of Cryptococcus was made by the API 20C yeast carbohydrate assimilation test, together with conventional procedures. These include the demonstration of chlamydospore production, germ tube test, urease test, nitrate assimilation test and colony morphology. The patient infected with Cryptococcus albidus var albidus had a good response to oral ketoconazole therapy, then the recovered and was discharged. The isolate obtained from this case may be regarded as an etiologic agent in fungemia.

Cryptococcosis↗
PubMed1990

Periorbital necrotising fasciitis due to Cryptococcus neoformans in a healthy young man.

A case report is presented of a healthy 25-year-old man who developed a periorbital necrotising fasciitis after a trivial trauma with a wooden splinter. Necrotising fasciitis of the eyelids occurs rarely. Cryptococcus neoformans is not described as a causative factor of necrotizing fasciitis. Cryptococcus neoformans usually infects patients with immunodeficiencies, diabetes mellitus or steroid therapy. This patient was healthy and developed a periorbital necrotising fasciitis due to Cryptococcus neoformans.

Adult↗
PubMed2025

Unisexual reproduction in the global human fungal pathogen Cryptococcus neoformans.

The human fungal pathogen Cryptococcus species complex (encompassing C. neoformans, C. deneoformans, and the C. gattii species complexes) exhibit diversity in sexual reproduction, including α-a mating, pseudosexual reproduction, as well as unisexual reproduction initiated from a single isolate or between isolates of the same mating type. A central conundrum is that while most Cryptococcus natural populations exhibit significant α mating-type bias, genetic and genomic analyses show recombination occurs in nature. The discovery of unisexual reproduction in C. deneoformans provided insight; however, thus far unisexual reproduction has never been directly observed in the predominant global pathogenic species C. neoformans. Here, we provide evidence that mutating the RIC8 gene, which encodes a conserved guanine nucleotide exchange factor (GEF) involved in both chaperoning and activating Gα proteins, enables unisexual reproduction in C. neoformans. Additionally, we show that genetic variation in the natural population promotes unisexual reproduction, and unisexual reproduction in C. neoformans involves canonical meiotic recombination. Finally, we found that deletion of both GPA2 and GPA3 in the MATα background leads to self-filamentation without sporulation, suggesting that differential modulation of the Gα proteins, likely involving Ric8, could underlie the switch between different modes of sexual reproduction in Cryptococcus. Our study further highlights that the highly conserved Ric8 GEF can act as an important regulator of cellular development in response to environmental stimuli and could modulate sexual reproduction in nature. We hypothesize that unisexual reproduction occurs much more frequently in nature than currently appreciated, and possibly in other fungi and microbial eukaryotes as well.

G protein↗
PubMed1978

An ultrastructural examination of the interaction between macrophages and Cryptococcus neoformans.

The interaction of mononuclear phagocytes with Cryptococcus neoformans was examined in vitro and in vivo using ultrastructural techniques. Immune serum roughens the surface of the yeast and in the first 2 hr, increases the number of organisms attaching to the macrophage surface, as well as the number of contacts between individual yeasts and the phagocyte. Contact is established by means of thin filopodia and cytoplasmic flaps. During the next few days the macrophages increase in size, and, by intimate apposition of their contiguous cell surfaces, a cellular barrier surrounds the now enclosed yeast. These events are accompanied by thinning of fungal capsule, degradation of the enclosed cryptococcus, and the formation of macrophage polykaryons. Electron cytochemical techniques for peroxidase reveal that these multinucleated cells are formed predominantly by the fusion of stimulated macrophages. Destruction of the enclosed yeast probably results from the secretion of various agents by the surrounding cells.

Animals↗
PubMed1986

Cryptococcus neoformans: comparisons of in vitro antifungal susceptibilities of serotypes AD and BC.

Thirty-nine isolates of Cryptococcus neoformans, nineteen serotype AD and twenty serotype BC, were assayed for susceptibility to eight antifungal agents using an in vitro agar dilution assay. Media employed were Kimmig agar and yeast nitrogen base supplemented with 10% glucose. The antifungal agents used were ketoconazole, amphotericin B, 5-fluorocytosine, nystatin, miconazole, BAY N 7133, ICI 153,066, and itraconazole. No clinically significant differences in vitro minimum inhibitory concentrations were detected between serotypes AD and BC against any of the compounds tested. An adverse medium effect was observed in two of the assays, but the outcome of the AD/BC comparison was not affected. This is the first report in which the in vitro antifungal susceptibilities of Cryptococcus neoformans serotypes are analyzed.

Amphotericin B↗
PubMed1978

Epidemiology of Cryptococcus neoformans.

The concept of the epidemiology of Cryptococcus neoformans as the causative agent of cryptococcosis and as a basidiomycetous yeast is based on the fact that bird manure has been until now its only known habitat but not plant material which likewise harbours various nonpathogenic Cryptococcus species. It could be shown that the possible influence of nutritional factors on the morphology and morphogenesis earns attention not only in view of the epidemiology of C. neoformans but of its perfect states, too.

Animals↗
PubMed1986

In vivo and in vitro studies with an atypical, rhinotropic isolate of Cryptococcus neoformans.

An atypical isolate of Cryptococcus neoformans was investigated because of its consistent and reproducible production of gross nasal pathology following i.v. injection in Swiss albino mice. Dose response to graded concentrations ranging from 1 X 10(2)-1 X 10(7) cells/mouse yielded an LD50 of 1.4 X 10(3) cells/mouse for the atypical rhinotropic strain H140 which was significantly less virulent (p less than 0.01) than our reference strain of Cryptococcus neoformans. There was no significant difference in mortality following the injection of in vitro vs. in vivo passed inoculum. As early as two weeks after inoculation, this strain produced gross nasal enlargement to approximately 2-3 X normal dimensions with granulomatous and ulcerated lesions. The LD60 resulted in the greatest percentage of nasal involvement (85%). C. neoformans was demonstrated by culture and histopathology in the noses, brains, lungs, livers and kidneys. A temperature selection was indicated by findings of a lower temperature minimum for subcultures isolated from the noses relative to those isolated from the brain, and by the fact that the most densely populated organs following intraperitoneal injection were the testes. This route of inoculation resulted in cutaneous nasal involvement in a manner analogous to that following i.v. injection. The atypical isolate was unable to assimilate trehalose or raffinose but otherwise was entirely consistent with identification as C. neoformans and produced characteristic CNS and general organ system disease in addition to the rhinotropic cutaneous manifestations. The model characterized here in normal mice may be of value in studies of fungal dermotropism.

Animals↗
PubMed1990

An anti-Cryptococcus neoformans monoclonal antibody directed against galactoxylomannan.

Six monoclonal antibodies (mAb) were produced by immunizing mice with a Cryptococcus neoformans serotype A spheroplast lysate (CNSL). Two mAb were of the IgG1 isotype; the others were IgM. The results obtained with one IgM mAb (CN6) are reported herein. This mAb recognized the four serotypes of C. neoformans and no cross-reactions were observed with extracts from Cryptococcus melibiosum, Candida albicans, Saccharomyces cerevisiae, Torulopsis glabrata or Trichosporon beigelii. Fractionation of the CNSL by gel filtration revealed that mAb CN6 recognized high molecular weight substances as well as a range of smaller molecules. Indirect ELISA inhibition studies showed that this mAb recognized substances in a cryptococcal culture filtrate. Inhibition studies and agglutination tests using latex beads sensitized with purified CN6 showed that CN6 strongly reacted with the C. neoformans serotype A cell envelope galactoxylomannan-mannoprotein complex (GAlXM-MP) and only weakly with the glucuronoxylomannan (GXM) component. These tests also showed that purified galactoxylomannan (GalXM) from C. neoformans serotype A was more reactive than purified mannoprotein (MP). An anti-GalXM mAb might be a useful tool for monitoring the clinical course of cryptococcal infections.

Animals↗