First report of Cryptococcus albidus septicaemia in an HIV patient

Titan cell formation is unique to Cryptococcus species complex

Members of the Cryptococcus species complex stand out by unique virulence factors that allowed evolutionary transition to pathogenesis. Among the factors contributing to cryptococcosis is a morphological transformation into giant (Titan) cells. It remains unclear whether species outside of the C. neoformans/C. gattii species complex are capable of titanization. We utilized two recently developed protocols that allow obtaining Titan cells in vitro to test if titanization occurs in non-C. neoformans/C. gattii species. We find that none of the tested strains, representing 10 species of basidiomycetous yeasts and the ascomycetous yeast Saccharomyces cerevisiae, undergo significant titanization under conditions that promote robust Titan cell formation in C. neoformans/C. gattii species complex. C. terreus formed occasional enlarged cells through a mechanism potentially similar to that of titanization. Our findings suggest that titanization is a rare phenomenon among basidiomycetous yeasts that occurs mostly in members of the C. neoformans/C. gattii species complex.

Cryptococcus albidus Fungemia in an Immunosuppressed Child: Case Report and Systematic Literature Review

Cryptococcus albidus, synonymous with Naganishia albida, rarely causes opportunistic infection in immunocompromised individuals. Its clinical features, particularly in children, are not well defined. Here, we report a case of C albidus fungemia in an immunosuppressed child; we also present results of a systematic review, for which we searched PubMed, Embase, and Web of Science using the keywords "cryptococcus" and "albidus." Our goal was to describe the spectrum of disease, diagnostic approaches, therapies, and outcomes. We identified 20 cases of invasive infection, only 2 of which involved children, and 7 cases of noninvasive infection. The reports originated in the Americas, Europe, and Asia. Of those with invasive infection, 16 (80%) patients had an underlying chronic disorder or had received immunosuppressive therapy, 8 (40%) had fungemia, and 6 (30%) had a central nervous system infection. The attributable case fatality rate was 40%. C albidus is an opportunistic yeast that can rarely cause life-threatening fungemia and central nervous system infection in individuals of any age, especially those who are immunocompromised.

First case of superficial infection due to Naganishia albida (formerly Cryptococcus albidus) in Iran: A review of the literature

Background and Purpose:

Naganishia albida (formerly Cryptococcus albidus) is a non-neoformans cryptococcal species rarely isolated as a human pathogen.

Case report:

Herein, we present the case of a 26-year-old Iranian man with a superficial cutaneous lesion in the axilla. The initial treatment for pityriasis versicolor by clotrimazole was unsuccessful. We performed skin sampling based on the standard protocol and conducted further investigations by the conventional laboratory tests and molecular analysis of the skin samples. All the mentioned analyses revealed N.albida as the causative agent of infection. The minimum inhibitory concentration (MIC) analysis was carried out for the isolated agent, and the patient was treated using 100 mg daily of oral itraconazole.

Conclusion:

N. albida can be the causative agent of some superficial infections. This is the first report on the successful detection and treatment of a superficial skin infection due to N. albida by oral itraconazole.

Systemic Cryptococcus Albidus Infection in a Doberman Pinscher

Cryptococcus albidus is a saprophytic, encapsulated yeast usually found in air, both outdoor and indoor, and sometimes on human skin. It is not usually considered to be a primary pathogen. Most cryptococcal infections of humans and animals are caused by Cryptococcus neoformans. Several cases of C. albidus infection have been reported in humans over the past 20 years. In the veterinary literature, 2 equine cases have been described: genital infection and mycotic keratitis. The present report is the first documented case of C. albidus systemic infection in a dog. Veterinarians and diagnosticians should be aware that C. albidus may be a potential canine pathogen.

Case Report of Cryptococcus Albidus Peritonitis in a Peritoneal Dialysis Patient and a Review of the Literature

Cryptococcus albidus is a saprophytic yeast linked to just 26 reports of human infection in the world literature. Here, we report the first case of C. albidus peritonitis, in a patient with end-stage renal disease and hepatitis C-associated cirrhosis who is on peritoneal dialysis. The patient was treated successfully with a week-long course of amphotericin B. Non-neoformans cryptococcal infections present a clinical challenge, because they are difficult to diagnose and lack established guidelines for treatment. We present a review of the literature on C. albidus infections and their treatment.

Cryptococcus albidus encephalitis in newly diagnosed HIV-patient and literature review

We present the first case of encephalitis caused by Cryptococcus albidus duo to AIDS. In addition, we give an overview of the literature of extra-dermal infection cases caused by C. albidus. In the 21 cases, HIV and organ transplantation were important risk factors especially in recent 20 years. Fungal culture or India ink preparations are the best way to demonstrate C. albidus in both serum and CSF.

The Basidiomycetous YeastsCryptococcus diffluensandC. liquefaciensColonize the Skin of Patients with Atopic Dermatitis

Our previous research showed that lipophilic yeasts, Malassezia species, colonize the skin of patients with atopic dermatitis (AD) at a high frequency. In this study, we found that two basidiomycetous yeasts, Cryptococcus diffluens and C. liquefaciens, colonize the skin significantly more frequently in AD patients than in healthy subjects. Transparent dressings were applied to the skin of 36 AD patients and 30 healthy subjects and then transferred onto Sabouraud dextrose agar. Colonies recovered from the medium were identified by DNA sequence analysis of internal transcribed spacer regions and the D1/D2 26S rRNA gene. C. diffluens and C. liquefaciens were isolated from 42% (15/36) and 33% (12/36) of AD patients and from 20% (6/30) and 20% (6/30) of healthy subjects, respectively. In addition, fungal DNA was extracted directly from the dressings and amplified in a specific nested PCR assay. C. diffluens and C. liquefaciens DNA were detected in dressings from 97% (35/36) and 86% (31/36) of the AD patients and 47% (14/30) and 37% (11/30) of the healthy subjects, respectively. These findings show that Malassezia spp. are not the only yeasts that colonize the skin of AD patients; Cryptococcus spp. also are present in a high proportion of patients. The role of these microorganisms in AD is as yet unknown, but the current findings, in combination with previous results, indicate that C. diffluens, C. liquefaciens, M. globosa, and M. restricta together colonize the skin surface of AD patients at a high frequency.

Isolation of Cryptococcus magnus and Cryptococcus chernovii from nasal cavities of pediatric patients with acute lymphoblastic leukemia

We report the isolation of Cryptococcus magnus and Cryptococcus chernovii in cultures inoculated with nasal specimens of pediatric cancer patients with acute lymphoblastic leukemia. The phenotypic characteristics of the isolates are described and their identity confirmed by sequencing of rDNA. Both species were resistant to caspofungin, anidulafungin, 5-flucytosine and itraconazole, but susceptible to amphotericin B, posaconazole and voriconazole. To the best of our knowledge, the isolation of these two species from nasal cavities has not been reported previously.

Virulence in Cryptococcus species

Cryptococcus neoformans and Cryptococcus gattii are the cause of life-threatening meningoencephalitis in immunocompromised and immunocompetent individuals respectively. The increasing incidence of cryptococcal infection as a result of the AIDS epidemic, the recent emergence of a hypervirulent cryptococcal strain in Canada and the fact that mortality from cryptococcal disease remains high have stimulated intensive research into this organism. Here we outline recent advances in our understanding of C. neoformans and C. gattii, including intraspecific complexity, virulence factors, and key signaling pathways. We discuss the molecular basis of cryptococcal virulence and the interaction between these pathogens and the host immune system. Finally, we discuss future challenges in the study and treatment of cryptococcosis.

False-positive culture results from patient tissue specimens due to contamination of RPMI medium with Cryptococcus albidus

Cryptococcus albidus, a rare opportunist, was isolated from biopsy specimens from three patients over 4 days. An investigation showed that the specimens had been contaminated by placement in RPMI medium. The importance of rapid communication between the microbiology laboratory, the infectious diseases/infection control division, and other involved parties in the event of unusual occurrences is highlighted.

Acute respiratory distress syndrome due toCryptococcus albiduspneumonia: Case report and review of the literature

Although cryptococcal infections due to Cryptococcus neoformans are frequently reported in the immunosuppressed patients, infections related to other Cryptococcus spp. are rarely reported. We are reporting a case of pulmonary infection and ARDS due to C. albidus in a patient receiving immunosuppressive therapy because of Still's disease. The diagnosis was made by tissue biopsy and culture. The patient responded to treatment with amphotericin B lipid complex 400 mg/day. The case is significant in that it reminds of yeasts as a cause of community acquired infection in the immunosuppressed patients.

Recombinant single-chain anti-idiotypic antibody: an effective fungal beta-1,3-glucan synthase inhibitor

Recombinant single-chain fragment variable anti-idiotypic antibodies were produced to represent the internal image of HM-1 killer toxin and were used as novel and effective antifungal agents to inhibit in vitro beta-1,3-glucan synthase and cell growth. The mechanism of cytocidal activity of anti-idiotypic antibodies was investigated and was compared with the actions of aculeacin A and papulacandin B, the most common antibiotics acting as beta-1,3-glucan synthase inhibitors. The degree of inhibition of beta-1,3-glucan synthase by both antibodies and antibiotics were examined for yeasts Saccharomyces cerevisiae A451, Cryptococcus albidus NBRC 0612 and Candida albicans IFM 40215. Although the mechanism of actions of the anti-idiotypic antibodies and antibiotics seems identical, the IC(50) values for the various yeasts used in this study confirmed that anti-idiotypic antibodies could be used as more effective fungal beta-1,3-glucan synthase inhibitors than those of antibiotics.

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.

First report of Cryptococcus albidus--induced disseminated cryptococcosis in a renal transplant recipient

Cryptococcus albidus, a non-neoformans species of the genus Cryptococcus, is generally regarded as a rare cause of disease. There have been only 14 previously reported cases in which this organism has been isolated as a pathogen, none of which occurred in a renal transplant recipient. A 23-year-old renal transplant recipient taking medication consisting of cyclosporine and prednisolone was admitted with a 10-day history of dry cough, fever and progressive dyspnea. The next day, his respiratory status deteriorated dramatically, and he developed acute respiratory distress syndrome (ARDS) and fulminant septic shock. On the eighth hospital day, tender macules on both his shins coalesced to form erythematous patches. Cryptococcus albidus was isolated by skin biopsy and tissue culture. We report here the first case of disseminated cryptococcosis caused by C. albidus in a renal transplant recipient who had been successfully treated with fluconazole monotherapy.

Effects of melanin upon susceptibility of Cryptococcus to antifungals

Melanin is a recognized virulence factor in Cryptococcus neoformans; several pathogenetic mechanisms have been suggested. We studied melanin as an antifungal resistance factor. The growth of laccase-active strains of C. neoformans and C. albidus in L-DOPA resulted in the production of black pigment. The formal minimal inhibitory concentrations (MICs) of amphotericin B and fluconazole were not changed by melanization. However, when we examined those wells which contained inhibited cells, we found live cells only in wells containing melanized C. neoformans. In contrast, melanization did not protect C. albidus from killing by amphotericin B. In an amphotericin B time-kill study of C. neoformans, significantly more melanized cells than non-melanized survived for the first few hours. Fluorescence microscopy and flow cytometry analyses showed that fewer melanized cells were stained with the fluorescent dye MitoRed. Incubation of MitoRed (the model) or amphotericin B with melanin extracted from C. neoformans decreased the free concentrations of these substances. Fluconazole, in contrast, was not removed from solution by melanin. This suggests that neoformans cryptococcal melanin deposited amphotericin B in the cell wall binds, reducing its effective concentrations.

Infections due to non-neoformans cryptococcal species

The incidence of infections due to non-neoformans cryptococcal species is increasing. Risk factors associated with infections due to these organisms include immunosuppression and clinical syndromes are similar to those encountered with Cryptococcus neoformans. Therapy with antifungal agents is often successful.

Laccase and melanization in clinically important Cryptococcus species other than Cryptococcus neoformans

The laccase enzyme and melanin synthesis have been implicated as contributors to virulence in Cryptococcus neoformans. Since isolations of Cryptococcus species other than C. neoformans from clinical specimens have been increasing, we examined the laccase activities of C. albidus, C. laurentii, C. curvatus, and C. humicola. Incubation of cells with epinephrine produced adrenochrome color in C. albidus, C. laurentii, and C. curvatus but not in C. humicola. Activity was always less than in C. neoformans. Laccase was detected in the soluble fractions of disrupted C. albidus, C. laurentii, and C. curvatus cells. Activity staining of partially purified enzyme after nondenaturing polyacrylamide gel electrophoresis revealed that laccases from C. albidus, C. laurentii, and C. curvatus migrated more slowly than that from C. neoformans. One strain of C. curvatus exhibited two melanin bands. Thus, several clinically emerging Cryptococcus species express laccase and can synthesize melanin.

Intraspecies diversity of Cryptococcus albidus isolated from humans as revealed by sequences of the internal transcribed spacer regions

The basidiomycetous yeast, Cryptococcus albidus, shows intraspecies diversity, but it is rarely isolated from immunocompromised patients. Nineteen strains of C. albidus, including nine clinical isolates, were re-classified by sequences of their rRNA internal transcribed spacer (ITS) regions. The nine clinical isolates were genetically diverse and included both C. albidus and C. diffluens. One clinical isolate, recovered from the blood of an AIDS patient, represented a new species. Only small differences were found in the biochemical and serological characteristics of C. albidus and C. diffluens. All isolates were sensitive to amphotericin B, but several isolates were resistant to fluconazole and itraconazole. C. albidus heterogeneity should be taken into consideration when identifying clinical isolates.

Serological relationships of Cryptococcus spp.: distribution of antigenic factors in Cryptococcus and intraspecies diversity

The antigenic formulas of 34 species in the genus Cryptococcus were determined by using type strains and eight factor sera prepared from adsorption experiments with Cryptococcus neoformans serotypes. These antigenic factors were shared by 19 species. The strains used could be divided into eight serological groups. The patterns of groups 1, 2, 3, 5, and 6 were the same as the patterns of C. neoformans serotypes A, D, A-D, B, and C, respectively. The species belonging to group 4 reacted to factor sera 1, 2, and 3. Group 7 contained one species that reacted only to factor serum 1. The 15 species in group 8 did not react to any of the factor sera used. Compared to the reported molecular phylogenetic tree, the serological and phylogenetic data were correlated in the Filobasidium lineage. All the members of the albidus clade in the Filobasidium lineage had antigens 1, 2, and 3, and all the strains in the magnus clade belonged to serogroup 8. Moreover, intraspecies diversity was examined using strains of C. curvatus, C. humicolus, and C. laurentii. Serological heterogeneity was observed in the species C. humicolus and C. laurentii, as well as in phylogenetic relationships previously published. Using serological features, similarities and differences between Cryptococcus species were demonstrated. Our study contributes to a better description of the genus Cryptococcus and related species phenotypically and phylogenetically.

Cutaneous cryptococcus infection due to C. albidus associated with Sézary syndrome

Cryptococcus albidus is a non-neoformans species of the genus Cryptococcus and is a rare cause of disease. There have been only 13 previously reported cases of systemic disease in which this opportunistic yeast has been isolated from the lung, cerebrospinal fluid and blood. We report the first case of cutaneous Cryptococcus infection due to the species C. albidus, in a man with Sézary syndrome.

Occurrence of Cryptococcus spp. in excreta of pigeons and pet birds

In pooled samples of faeces from 25 pet bird flocks in Thuringia, a high rate of contamination with Cryptococcus neoformans var. neoformans was found. The prevalence of Cr. neoformans in the bird-breeding establishments correlated with the numbers of the different pet bird species in these flocks. The differentiation between varieties of Cr. neoformans by means of proline assimilation and canavanine resistance detection as well as with the aid of Cr. neoformans factor sera, polymerase chain reaction (PCR) fingerprinting, sequencing of PCR products as well as Fourier transform infrared spectroscopy showed uniform results which also corresponded to the serological differentiation between serovars A and D. A predominance of serovar A could be observed among the pet bird breeding flocks. This corresponded to the frequency distribution of serovars A and D in cases of human diseases in Germany. In 50% of the samples of pigeon excreta examined (n = 30) in Innsbruck (Austria), Cryptococcus albidus could be isolated but not Cr. neoformans. However, this Cryptococcus species is of minor pathogenetic importance for man. Cryptococcus albidus may be clearly distinguished from Cr. neoformans by means of microbiological methods, PCR and Fourier transform infrared spectroscopy.

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 5prime 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.Key words: basidiomycetous yeasts, taxonomy, Cryptococcus albidus, ribosomal DNA, molecular systematics.

Fungaemia due to Cryptococcus laurentii and a review of non-neoformans cryptococcaemia

Cryptococcus laurentii is one of several non-neoformans cryptococci that have rarely been associated with human infection. The spectrum of clinical infection due to non-neoformans species ranges from skin lesions to fungaemia. Most cases of non-neoformans fungaemia have been nosocomially acquired and have been associated with indwelling intravascular catheters and neutropenia. Limited data on in vitro susceptibilities of non-neoformans cryptococci show these species to be more resistant to fluconazole and flucytosine than most Cr. neoformans. Two such cases are presented here.