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Cryptococcus laurentii fungemia in a premature neonate.

Cryptococcus spp. other than Cryptococcus neoformans are generally considered nonpathogenic to humans. There are only 15 case reports of disease in humans caused by Cryptococcus laurentii infection. Underlying diseases and predisposing risk factors seem to play an important role in these cases. Our patient is the first case of an extremely low birth weight infant with C. laurentii fungemia reported in the English literature. In our case, the MIC of amphotericin B for C. laurentii was 0.25 to 1 microg/ml and the patient had a good outcome following the administration of amphotericin B at 10 mg/kg combined with central venous catheter removal. There will undoubtedly be an increasing occurrence of unusual fungal infections accompanying further advances in medicine. A high degree of suspicion and improvements in the techniques for culture and identification will contribute to the earlier diagnosis and treatment of unusual fungal infections.

Adolescent↗

Cryptococcus infection in tropical Australia.

Eighteen cases of disease caused by the saprophytic fungi Cryptococcus neoformans and Cryptococcus bacillisporus are described from the Northern Territory of Australia. The majority of infections were with Cryptococcus bacillisporus and in the rural Aboriginal population, often causing pulmonary mass lesions.

Amphotericin B↗

Cryptococcus festucosus sp. nov. a new hymenomycetous yeast in the Holtermannia clade.

Five yeast strains belonging to the genus Cryptococcus Vuillemin were isolated from steppe plants and turf collected in the Prioksko-terrasny biosphere reserve (Moscow region, Russia). Sequence analyses of the D1/D2 domains of the 26S rDNA and of the internal transcribed spacer region revealed that these yeast strains and strain CBS 8016 have almost identical sequences and belong to the Holtermannia clade of the Tremellomycetidae (Basidiomycota, Hymenomycetes). A novel species named Cryptococcus festucosus (type strain VKM Y-2930) is proposed to accommodate these strains. Physiological characteristics and mycocin sensitivity patterns distinguishing Cryptococcus festucosus from the other species of this clade are presented.

Antifungal Agents↗

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↗

In vitro susceptibility to antifungal agents of environmental Cryptococcus spp. isolated in the city of Ribeirão Preto, São Paulo, Brazil.

Infections by Cryptococcus strains other than C. neoformans have been detected in immunocompromised patients. Of these strains, three are considered human pathogens: C. albidus, C. laurenttii, and C. uniguttulatus. This study deals with the in vitro susceptibility of Cryptococcus to drugs such as amphotericin B, itraconazole, fluconazole, and 5-fluorocytosine. Environmental Cryptococcus isolates (50) distributed as follows: C. neoformans var. neoformans (16), C. albidus (17), C. laurentii (14), and C. uniguttulatus (3) were evaluated by the micro and macrodilution techniques, according to EUCAST and NCCLS recommendations, respectively. Considering both methodologies the respective minimal inhibitory concentrations (MIC) were 0.125 and 2 microg/ml for amphotericin B, 0.06 and 8 microg/ml for itraconazole, and 0.5 and more than 64 microg/ml for fluconazole and 5-fluorocytosine. Agreement percentages for the two methodologies were 100% for amphotericin B and fluconazole for all the strains tested. For itraconazole, the agreement percentage was 81.3% in the C. neoformans strain and 100% for all the others. All species had a agreement percentage of 94.1 to 100% when susceptibility to 5-fluorocytosine was tested. It is concluded that environmental isolates of C. neoformans var. neoformans, C. albidus, C. laurentii, and C. uniguttulatus may show high MICs against certain drugs, suggesting in vitro primary resistance to the antifungals tested.

Amphotericin B↗

Cryptococcus gattii in AIDS patients, southern California.

Cryptococcus isolates from AIDS patients in southern California were characterized by molecular analyses. Pheromone MFalpha1 and MFa1 gene fragments were polymerase chain reaction-amplified with fluorescently labeled primers and analyzed by capillary electrophoresis (CE) on DNA analyzer. CE-fragment-length analyses (CE-FLAs) and CE-single-strand conformation polymorphisms (CE-SSCPs) were used to determine Cryptococcus gattii (Cg), C. neoformans (Cn) varieties neoformans (CnVN) and grubii (CnVG), mating types, and hybrids. Corroborative tests carried out in parallel included growth on specialized media and serotyping with a commercial kit. All 276 clinical strains tested as haploid MATalpha by CE-FLA. CE-SSCP analyses of MFalpha1 showed 219 (79.3%) CnVG, 23 (8.3%) CnVN, and 34 (12.3%) Cg isolates. CE-FLA and CE-SSCP are promising tools for high-throughput screening of Cryptococcus isolates. The high prevalence of Cg was noteworthy, in view of its sporadic reports from AIDS patients in North America and its recent emergence as a primary pathogen on Vancouver Island, Canada.

AIDS-Related Opportunistic Infections↗

Cryptococcus neoformans granuloma in the lung and spinal cord of a free-ranging cheetah (Acinonyx jubatus). A clinical report and literature review.

A 6-year-old, male, wild-born, free-ranging cheetah (Acinonyx jubatus) was evaluated for acute onset of progressive lameness in the right hind limb. Survey radiographs were unrewarding and myelography indicated an intramedullary compressive mass at the L3-L4 region. A fine needle aspirate of the lesion indicated the presence of Cryptococcus organisms. Necropsy confirmed the presence of granulomas (cryptococcoma) in the lung and the spinal cord (meningomyelitis) caused by Cryptococcus neoformans var. gattii. Cryptococcus neoformans is a yeast-like organism that is a potential pathogen to many species. Initial infection is thought to be of respiratory origin and then it commonly disseminates systemically from the nasal cavity or lungs to the skin, eyes and central nervous system in particular. The cheetah tested negative for both feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV), as have all the previously reported cheetah cases. C. neoformans is a non-contagious, opportunistic organism and is the most common systemic mycoses in domestic cats and the cheetah.

Acinonyx↗

[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↗

Diversity in the yeast Cryptococcus albidus and related species as revealed by ribosomal DNA sequence analysis.

Evidence accumulated from studies based on physiological, biochemical, and molecular characteristics has pointed to the heterogeneity of the ubiquitous anamorphic basidiomycetous yeast species Cryptococcus albidus (Saito) Skinner, with its current varieties and synonyms. The taxonomic status of this species has not been reappraised because different studies, mostly involving limited numbers of strains, have not been integrated. To assess species diversity within the clade containing Cryptococcus albidus and other phylogenetically related Cryptococcus and Filobasidium species, we determined ribosomal DNA (rDNA) sequences of 69 strains from the 5' end of the 26S gene, D1/D2 region, and in some cases, the non-coding ITS2 region. Analysis of the sequence data together with available physiological, biochemical, and molecular characteristics, showed the segregation of C. albidus into at least 12 species, leading to the elevation of former varieties to the rank of species (C. aerius, C. diffluens), the reinstatement of synonyms (C. liquefaciens, C. terricola), and the proposal of new species (C. arrabidensis, C. chernovii, C. cylindricus, C. oeirensis, C. phenolicus, C. saitoi, C. uzbekistanensis, C. wieringae). The overall analyses of the results argue in favour of the use of rDNA sequence data to improve species delineation when integrated with other available physiological and molecular characteristics.

Basidiomycota↗

[Appraisal of fungistatic and fungicidal activities of quaternary compounds towards yeasts belonging to the genera Candida and Cryptococcus].

The fungistatic and fungicidal activities of five quaternary ammonium compounds towards Candida and Cryptococcus strains were determined using a bacteriological method adapted to mycological experiments. It could be deduced from this study that Cryptococcus in spite of the capsule around the cell were more sensitive than Candida and that the benzethonium chloride (BC) exhibited the most effective action against the whole yeasts. No resistance appeared, only Cryptococcus strain was less sensitive than the others.

Anti-Infective Agents, Local↗

[Morphological observation of the endogenous endophthalmitis of cryptococcus neoformans].

PURPOSE: To observe the pathologic change of the endogenous endophthalmitis of cryptococcus neoformans. METHODS: Light and electron microscope were used. RESULT: The choroid was focally tumor-like by an inflammatory cells infiltrate, which consisted of multinucleated gicant, epithelioid cells and lymphocytes. Special stains (Grocott's methnamine silver, PAS, alcian blue) and electron microscope disclosed the budding form of cryptococcus neoformans. CONCLUSION: The morphologic examinations are only an effectivel method of diagrosing the endogenous endophthalmitis of cryptococcus neoformans.

Adult↗

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↗

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↗

[The thermotolerance of the Cryptococcus. Investigation on 208 wild and type cultures strains (author's transl)].

The maximal temperature for growth was investigated on 208 Cryptococcus, 2 type cultures and 206 wild strains, belonging to 11 species or varieties. According to the results, which spread from 25 degrees to 42 degrees, the Cryptococcus were separated in three groups. The differentiation of C. neoformans from other Cryptococcus developing at 37 degrees, and particularly from two species with near bio-chemical characteristics, was discussed.

Cryptococcus↗

[Variability of Cryptococcus species in the capacity to form pseudomycelia].

Treatment of the type strains of Cryptococcus flavus, Cr. gastricus, Cr. magnus and Cr. hungaricus with nitrosoguanidine yielded mutants which were capable of producing the pseudomycelium. The mutants almost did not differ from the parent cultures in other diagnostic characteristics. Certain species of Candida and Cryptococcus were found to be very similar in taxonomic properties. Apparently, pseudomycelial saprophytic cryptococci might exist in nature. The conclusion has been drawn that the ability for pseudomycelium formation (its absence) should not be used as a generic criterion for Cryptococcus spp.

Candida↗

Down-regulation of the afferent phase of T cell-mediated pulmonary inflammation and immunity by a high melanin-producing strain of Cryptococcus neoformans.

The interaction(s) between cryptococcal virulence factors and leukocytes involved in generating protective cell-mediated immunity is not well defined. Intratracheal inoculation of Cryptococcus neoformans strain 52 induced a vigorous T cell-mediated pulmonary inflammatory response that controlled the growth of the organism. In contrast, strain 145 induced a pulmonary inflammatory response that was delayed in onset, slower to develop, and ineffective in controlling the infection. In addition, the expansion of cryptococcus-specific lymphocytes in the pulmonary lymph nodes and titer of specific Abs in the serum of strain 145-infected mice were both diminished markedly. Of the known cryptococcal virulence factors, these two strains differed only in melanin production (52-low and 145-high). Heat-killed strain 145 cryptococci (HKC-145) that had been rendered melanin-negative induced TNF-alpha production by alveolar macrophages in vitro and stimulated vigorous cryptococcus-specific lymphoproliferation. In contrast, high melanin-containing HKC-145 inhibited TNF-alpha production and lymphoproliferation. In vivo, mice infected with melanin low strain 52, but not melanin high strain 145, had elevated levels of TNF-alpha in the bronchoalveolar lavage fluid. Mice co-infected with strains 145 and 52 generated a pulmonary inflammatory response resulting in increased long-term survival. Taken together, these studies demonstrate that melanin does not protect cryptococci from being eliminated in vivo by recruited, activated effector cells; but melanin can inhibit the recognition of the organism by host defenses, thereby down-regulating the afferent phase of T cell-mediated immunity, e.g., TNF-alpha production and lymphoproliferation.

Animals↗

Afferent phase production of TNF-alpha is required for the development of protective T cell immunity to Cryptococcus neoformans.

The development of T cell immunity is required to clear a pulmonary Cryptococcus neoformans infection (via the recruitment and activation of inflammatory cells). The objective of our studies was to determine whether TNF-alpha is required during the afferent phase of the response. The levels of TNF-alpha mRNA and protein in the lungs increased following intratracheal inoculation of CBA/J mice with C. neoformans 52 and preceded the development of an inflammatory response in the lungs. Administration of neutralizing TNF-alpha-specific antiserum on days 0, 3, 6, and 9 reduced inflammatory cell recruitment by 80% on day 13, resulting in a 3-fold increase in lung C. neoformans CFU. The number of CD4+ T cells was decreased by 65%, the number of neutrophils was decreased by 84%, and the number of macrophages was decreased by >98%. Strikingly, a single dose of neutralizing anti-TNF-alpha serum was sufficient to prevent the development of protective cell-mediated immunity on day 35 if administered on day 0, but was ineffective if delayed until day 14. Day 0 anti-TNF-alpha-treated mice could not generate cryptococcus-specific delayed type hypersensitivity reactivity, clear the infection from their lungs (10(4)-fold increase in CFU), control dissemination to the spleen and brain (10(5)- and 10(6)-fold increases in CFU), or adoptively transfer cryptococcus-specific immunity (mononuclear cell recruitment into the lungs following intratracheal challenge or footpad delayed type hypersensitivity). Thus, the production of TNF-alpha during the afferent phase of the immune response against a pulmonary C. neoformans infection (before day 14) is critical for the development of protective T cell immunity in both the lungs and extrapulmonary sites.

Animals↗

PRODUCTION OF DELAYED HYPERSENSITIVITY TO CRYPTOCOCCUS NEOFORMANS IN EXPERIMENTAL ANIMALS.

Lomanitz, Rachel (University of Oklahoma School of Medicine, Oklahoma City) and John M. Hale. Production of delayed hypersensitivity to Cryptococcus neoformans in experimental animals. J. Bacteriol. 86:505-509. 1963.-Rabbits and guinea pigs have been sensitized to somatic, as well as whole-cell, antigens of a small-capsuled variant of Cryptococcus neoformans ODH-DV. Rabbits have also been sensitized to soma and to whole cells of a large-capsuled patient isolate. The time required for appearance of skin reactivity, after intracutaneous injection of antigenic material, indicated that the hypersensitivity developed was of the delayed type. This was subsequently demonstrated in both rabbits and guinea pigs by passive transfer of the hypersensitivity to normal animals. Efforts to transfer the skin sensitivity to normal rabbits with serum from sensitized animals were unsuccessful, indicating that humoral antibodies are not involved. Preliminary studies suggest that the sensitizing antigen resides in the cell wall and is highly specific.

Animals↗