Cryptococcus neoformans varieties as agents of cryptococcosis in Brazil

The study of the clinical isolates of Cryptococcus neoformans from 83 Brazilian patients with disseminated cryptococcosis showed that 75 were C. neoformans var. neoformans and 8 were var. gattii. Twenty-seven isolates were serotyped; all 19 var. neoformans were serotype A and all 8 var. gattii were serotype B. The correlation of the varieties of C. neoformans with the presence or not of hosts predisposing conditions to the mycosis showed that: (1) cryptococcosis caused by gattii variety occurred in 7 (58.3%) of the 12 nonimmunosuppressed patients, and (2) cryptococcosis caused by neoformans variety occurred in 65 (98.5%) of the 66 AIDS patients and in all 5 patients with other immunosuppressive conditions. The comparison of the distribution of the gattii and neoformans varieties between the nonimmunosup-pressed and immunosuppressed patients showed a significant statistical difference (p < 0.01).     

Cryptococcosis in HIV-negative Patients with Renal Dialysis: A Retrospective Analysis of Pooled Cases

Cryptococcosis is a lethal fungal infection mainly caused by Cryptococcus neoformans/C. gattii species. Currently, our understanding of cryptococcosis episodes in HIV-negative patients during renal dialysis remains scarce and fragmented. Here, we performed an analysis of pooled cases to systemically summarize the epidemiology and clinical characteristics of cryptococcosis among HIV-negative patients with renal dialysis. Using pooled data from our hospital and studies identified in four medical databases, 18 cases were identified and analyzed. The median duration time of renal dialysis for peritoneal renal dialysis and hemodialysis cases was 8 months and 36 months, respectively. Several non-neoformans/gattii species were identified among the renal dialysis recipients with cryptococcosis, particularly Cryptococcus laurentii and Cryptococcus albidus, which share similar clinical manifestations as those caused by C. neoformans and C. gattii. Our analyses suggest that physicians should consider the possibility of the occurrence of cryptococcosis among renal dialysis recipients even when cryptococcal antigen test result is negative. The timely removal of the catheter is crucial for peritoneal dialysis patients with cryptococcosis. In addition, there is a need for optimized antifungal treatment strategy in renal dialysis recipients with cryptococcal infections.     

<Emphasis Type="Italic">Cryptococcus gattii</Emphasis>: Clinical Importance and Emergence in North America

Cryptococcus gattii is an emerging fungal pathogen in the Pacific Northwest of North America, where it has caused more than 50 human infections since its emergence in 2004. Among residents of British Columbia, where the disease emerged in 1999 on Vancouver Island, many infections have occurred in immunocompetent persons. The cause for the emergence is currently unknown. The pathogenic profile of Cryptococcus gattii in North American patients appears to be different from that seen previously for C. gattii and from the profile of infection among patients with Cryptococcus neoformans. Treatment duration and the need for patient follow-up may be different between patients infected with C. gattii and C. neoformans. For this reason, physicians treating atypical patients with Cryptococcal spp infection, particularly HIV-uninfected patients, should obtain a travel history and obtain a species identity for Cryptococcus isolates.     

Cryptococcus neoformàns var. gattii among patients with cryptococcal meningitis in Mexico. First observations

A retrospective study of 20 patients with cryptococcal meningitis and their isolated strains was performed. Cryptococcus neoformans var. neoformans was recovered from 14 (70%) cases, and var. gattii was recovered from six (30%) patients. Twelve patients had AIDS (all carrying var. neoformans), two had other diseases (one with var. neoformans and one var. gattii) and there was no identifiable underlying disease in six (one var. neoformans and five var. gattii). Fourteen patients (11 var. neoformans and three var. gattii) resided in the Mexico City area, where a temperate climate is prevalent, and there were six cases (three var. neoformans and three var. gattii) from states with a tropical/subtropical climate. Although there was no significant statistical difference between the two varieties, the fatal outcome was higher in patients with var. neoformans. The disease caused by var. gattii strains was characterized by a higher opening pressure, more inflamatory changes of CSF and a longer clinical course (delayed clinical and mycological cure). Cryptococcus neoformans var. gattii is a significant cause of cryptococcal meningitis in patients without underlying diseases in Mexico.     

Tongue lesion due to Cryptococcus neoformans as the first finding in an HIV-positive patient

BackgroundCryptococcosis is a severe universally distributed mycosis which mainly affects immunocompromised hosts. This mycosis is caused by yeasts of two species complex of the genus Cryptococcus: Cryptococcus neoformans and Cryptococcus gattii. Meningeal cryptococcosis is the most frequent clinical presentation of this disseminated mycosis. The oral mucosa involvement is extremely unusual.Case reportWe present a case of cryptococcosis with an unusual clinical form. The patient was assisted because she had an ulcerated lesion on the lingual mucosa. Encapsulated yeasts compatible with Cryptococcus were found in microscopic exams of wet preparations from lingual ulcer clinical samples obtained for cytodiagnosis and mycological studies. Cryptococcus neoformans (C. neoformans var. grubii VNI) was isolated in culture. This patient did not know her condition of HIV seropositive before the appearance of the tongue lesion.ConclusionsThe involvement of the oral mucosa is uncommon in this fungal infection, but is important to include it in the differential diagnosis in HIV positive patients.     

Cryptococcus neoformans: A central nervous system isolate from an AIDS patient that is rhinotropic in a normal mouse model

A strain of Cryptococcus neoformans that was isolated from the cerebrospinal fluid of a human diagnosed as having acquired immunodeficiency syndrome (AIDS), and that produced cutaneous lesions in experimentally infected, normal mice is described. Although no unusual cutaneous manifestations were noted in the patient's records, this isolate of C. neoformans proved to be dermotropic when injected intravenously into CD-1 mice. The LD₅₀ at 28 days post infection ranged from 3.6–7.5×10⁵ cells per mouse, and in vitro growth rate studies demonstrated that this isolate grew well at 35 °C and at 37 °C, but did not grow at 40 °C and higher. This isolate was rhinotropic producing large granulomatous lesions in the nasal tissues. Other cutaneous tissues affected were the periocular tissues, ears, feet and tail, although the granulomas were nodular in structure and less necrotic than the nasal lesions. The brain, lungs, liver, kidneys and spleen also were culture positive for C. neoformans. Histopathologically, each affected tissue examined had large densities of yeast cells and a chronic, granulomatous host response. Animals surviving the infection appeared to develop a commensal-type relationship with the infective yeast. This is the first report of an isolate of C. neoformans from an AIDS patient that has caused cutaneous manifestations in an animal model. The model described in this report may be useful for elucidating pathogenic mechanisms of cryptococcosis, particularly cutaneous manifestations of the disease.     

Successful treatment of Cryptococcus gattii neurocryptococcosis in a 5-year-old immunocompetent child from the French Guiana Amazon region

Compared to the incidence in adults, cryptococcosis is rare among children. We report a case of neurocryptococcosis due to Cryptococcus gattii in a five-year-old girl without identified risk factors living in French Guiana. Neurological surgery in combination with long-term antifungal treatment with amphotericin B and 5-flucytosine successfully resolved the cryptococcal infection. Subsequent molecular characterization of the Cryptococcus isolate revealed that the infection was caused by a C. gattii genotype AFLP6B/VGIIb strain.     

Clinical and environmental isolates of Cryptococcus neoformans in Bangkok (Thailand)

Cryptococcus neoformans was isolated from 13 patients (7 females and 6 males) suffering from systemic cryptococcosis. Eight patients were suffering from central nervous system cryptococcosis and 5 were suffering from disseminated cryptococcosis. Systemic lupus erythematosus was found to be the common underlying disease in 3 patients. The results of treatment depended on the underlying diseases (7 improved, 6 died). Also, 13 isolates of C. neoformans were obtained from feces of 30 pet birds. All 26 isolates of C. neoformans were cultured in glycine cycloheximide medium and were found to be of serotypes A and D.     

Atypical Micromorphology and Uncommon Location of Cryptococcosis: A Histopathologic Study Using Special Histochemical Techniques (One Case Report)

Here we report an unusual case of disseminated cryptococcosis in a patient with AIDS. Although typical Cryptococcus neoformans micromorphology was observed in tongue biopsy, cervical lymph node examination revealed atypical histopathologic findings. These included pseudohyphae, chains of budding yeasts and structures resembling germ tubes. Cryptococcus neoformans infection in supraclavicular lymph nodes was also confirmed by culture. The importance of using special histochemical techniques—Mayer’s mucicarmine stain for mucicarminophilic capsule and Grocott’s silver stain—in the diagnosis of cryptococcosis is reinforced.     

Isolation of Cryptococcus laurentii from Canada Goose guano in rural upstate New York

Cryptococcus neoformans and Cryptococcus gattii are etiologic agents of cryptococcal pneumonia and meningitis, potentially lethal syndromes associated with AIDS. A related species, Cryptococcus laurentii, has recently been implicated in several cases of human disease. Guano from Canada Goose (Branta canadensis), an organism that lives closely beside man and inhabits recreational space in rural and suburban areas, might be a significant environmental reservoir of Cryptococcus organisms in non-urban areas. Cryptococcal organisms were isolated from Canada Goose guano from a site in rural northern New York, with identification based upon colony and microscopic morphology, ability to metabolize l-Dopa to melanin, and positive reaction with a commercial anti-cryptococcal capsular polysaccharide latex bead agglutination test. DNA sequences from five positive isolates were identical to each other, and identical to the ITS1-5.8S-ITS2 sequences of C. laurentii strain CBS7140 (Accession AY315665) across a 511 bp sequence. All five isolates of C. laurentii possess three of the known virulence factors common to cryptococcal organisms that cause human disease: capsule, ability to grow at 37 °C, and laccase activity.     

Intra-abdominal Cryptococcosis by Cryptococcus gattii: Case Report and Review

Although abdominal cryptococcomas and visceral cryptococcal lymphadenitis as part of disseminated fungal infection have been reported mostly in HIV-infected patients, localized intra-abdominal involvement due to Cryptococcus gattii has not been previously described in non-HIV-infected patients. In general, a smaller proportion of cryptococcosis is caused by C. gattii. We report here on a type II diabetic HIV-negative patient who presented with a localized intra-abdominal cryptococcal mass due to C. gattii. In addition, we review the general aspects of intra-abdominal and gastrointestinal involvement by Cryptococcus neoformans in the literature and discuss the importance of identifying the C. neoformans varieties and C. gattii in routine laboratories.     

Intestinal Lesion in a Dog Due to <Emphasis Type="Italic">Cryptococcus gattii</Emphasis> Type VGII and Review of Published Cases of Canine Gastrointestinal Cryptococcosis

Cryptococcosis is a mycosis caused by yeasts of genus Cryptococcus, mainly the species C. neoformans and C. gattii that can affect humans and animals. These yeasts are widely distributed in the environment and are typically associated with avian droppings and decaying wood. Most infections are related to the respiratory tract, but the central nervous system and cutaneous lesions are also reported in the literature. The present report is a case of cryptococcosis in an 18-month-old unspayed female English Bulldog with the main complaint of weight loss and diarrhea. The presence of two large masses observed in an ultrasound examination leads us to perform an exploratory laparotomy. Considering the size of the lesion and the impossibility of owner to provide intensive care, the consent for euthanasia was requested. The postmortem diagnosis of cryptococcosis was revealed by cytological evaluation, and the involvement of C. gattii VGII was confirmed by isolation and identification tests as well as by the detection of the URA5 gene restriction fragment length polymorphism PCR analysis. Reports in the literature of the involvement of Cryptococcus in gastrointestinal lesions are rare in both human and veterinary medicine. Data about different forms of cryptococcosis are important to provide more knowledge of uncommon clinical presentations of this yeast and therefore improve the diagnoses and decisions for the best therapy.     

Cryptococcus gattii, No Longer an Accidental Pathogen?

Cryptococcus gattii is an environmentally occurring pathogen that is responsible for causing cryptococcosis marked by pneumonia and meningoencephalitis in humans and animals. C. gattii can form long-term associations with trees and soil resulting in the production of infectious propagules (spores and desiccated yeast). The ever-expanding number of reports of clinical and environmental isolation of C. gattii in temperate climates strongly imply that C. gattii occurs worldwide. The key ability of yeast and spores to enter, survive, multiply, and exit host cells, and to infect immunocompetent hosts distinguishes C. gattii as a primary pathogen and suggests evolution of C. gattii pathogenesis as a result of interaction with plants and other organisms in its environmental niche. Here we summarize the historical literature on C. gattii and recent literature supporting the worldwide occurrence of the primary pathogen C. gattii.     

Vaccine-Mediated Immune Responses to Experimental Pulmonary Cryptococcus gattii Infection in Mice

Cryptococcus gattii is a fungal pathogen that can cause life-threatening respiratory and disseminated infections in immune-competent and immune-suppressed individuals. Currently, there are no standardized vaccines against cryptococcosis in humans, underlying an urgent need for effective therapies and/or vaccines. In this study, we evaluated the efficacy of intranasal immunization with C. gattii cell wall associated (CW) and/or cytoplasmic (CP) protein preparations to induce protection against experimental pulmonary C. gattii infection in mice. BALB/c mice immunized with C. gattii CW and/or CP protein preparations exhibited a significant reduction in pulmonary fungal burden and prolonged survival following pulmonary challenge with C. gattii. Protection was associated with significantly increased pro-inflammatory and Th1-type cytokine recall responses, in vitro and increased C. gattii-specific antibody production in immunized mice challenged with C. gattii. A number of immunodominant proteins were identified following immunoblot analysis of C. gattii CW and CP protein preparations using sera from immunized mice. Immunization with a combined CW and CP protein preparation resulted in an early increase in pulmonary T cell infiltrates following challenge with C. gattii. Overall, our studies show that C. gattii CW and CP protein preparations contain antigens that may be included in a subunit vaccine to induce prolonged protection against pulmonary C. gattii infection.     

Fluconazole Alters the Polysaccharide Capsule of Cryptococcus gattii and Leads to Distinct Behaviors in Murine Cryptococcosis

Cryptococcus gattii is an emergent human pathogen. Fluconazole is commonly used for treatment of cryptococcosis, but the emergence of less susceptible strains to this azole is a global problem and also the data regarding fluconazole-resistant cryptococcosis are scarce. We evaluate the influence of fluconazole on murine cryptococcosis and whether this azole alters the polysaccharide (PS) from cryptococcal cells. L27/01 strain of C. gattii was cultivated in high fluconazole concentrations and developed decreased drug susceptibility. This phenotype was named L27/01_F, that was less virulent than L27/01 in mice. The physical, structural and electrophoretic properties of the PS capsule of L27/01_F were altered by fluconazole. L27/01_F presented lower antiphagocytic properties and reduced survival inside macrophages. The L27/01_F did not affect the central nervous system, while the effect in brain caused by L27/01 strain began after only 12 hours. Mice infected with L27/01_F presented lower production of the pro-inflammatory cytokines, with increased cellular recruitment in the lungs and severe pulmonary disease. The behavioral alterations were affected by L27/01, but no effects were detected after infection with L27/01_F. Our results suggest that stress to fluconazole alters the capsule of C. gattii and influences the clinical manifestations of cryptococcosis.     

Ecological niche of <Emphasis Type="Italic">Cryptococcus neoformans</Emphasis> var. <Emphasis Type="Italic">grubii</Emphasis> and <Emphasis Type="Italic">Cryptococcus gattii</Emphasis> in decaying wood of trunk hollows of living trees in Jabalpur City of Central India

Cryptococcus neoformans var. grubii and C. gattii were repeatedly isolated from decaying wood of trunk hollows in living trees growing in Jabalpur City in Central India. The isolation of C.␣gattii has been reported from decayed wood inside trunk hollow of Tamarindus indica (15.6%), Mangifera indica (2.2%), Pithecolobium dulce (12.5%), Syzygium cumini (14%), and one from bark of S.␣cumini. C. n. var. grubii was isolated from decaying wood debris of T. indica (4.4%), M. indica (13.3%), Terminalia arjuna (25%), S. cumini (2%), Cassia fistula (4.5%), and two from bark of S. cumini. The two varieties never co-occurred in the same hollow. C. gattii and C. n. var. grubii isolates belonged to serotype B and serotype A respectively. The data strongly supported the colonization of the pathogen in␣decaying wood hollow of all six-tree species. Evidence of this was found by repeated isolation up to 820 days. P. dulce is being reported for the first time as natural habitat of C. gattii and T.␣arjuna and C. fistula as natural habitat for C. n. var. grubii. M. indica is being reported for the second time as the natural habitat of both varieties (C. n. var. grubii and C. gattii). The population density of these pathogens from decaying wood debris of various tree species ranged between 0.5 × 10³ cells/g and 6 × 10⁵ cells/g. The seasonal variation has been seen in isolation of this yeast. Our result further reinforce the recently emerging evidence that the natural habitat of C. n. var. grubii and C. gattii is more generalized.     

Selection of Optimal Host Strain for Molecular Pathogenesis Studies on <Emphasis Type="Italic">Cryptococcus gattii</Emphasis>

Encapsulated yeast, Cryptococcus gattii (Cg) is a primary and emerging fungal pathogen in North America. It has a predilection for invading the central nervous system of both healthy and immunocompromised humans and animals. Recently, we initiated molecular pathogenesis studies in Cg strain NIH444 (ATCC 32609). In this report, we compared the biology and pathogenic potential of NIH444 to those of WM276, an Australian environmental isolate that is being used for the whole genome-sequencing project. Our data indicated that NIH444 is comparatively more virulent in a mouse model of cryptococcosis than is WM 276. We found robust mating of NIH444, and no mating of WM276, when tested against Cg MATa strain, NIH198. WM276 but not NIH444 was defective in filamentation and sporulation (haploid fruiting). Interestingly, NIH444 has a VGII/AFLP6 genotype similar to that of the genotype of the recent outbreak strains from Vancouver Island, British Columbia, Canada. Additionally, comparisons of nucleotide sequences of various genes also showed differences between NIH444 and WM276. Based on these observations, we conclude that NIH444 should remain the strain of choice for understanding Cg pathogenesis, especially on the North American continent.     

Serotypes of Cryptococcus neoformans isolated from patients prior to and during the AIDS era in Thailand

One hundred and eighty-seven strains of Cryptococcus neoformans isolated from patients in Thailand were charcterized by biochemical varieties relating to serogroups. Canavanine-glycine-bromothymol blue (CGB) agar was used for differentiating the varieties of C. neoformans. Slide agglutination tests were performed with Crypto Check (Iatron, Inc., Tokyo) to determine their serotypes. Fifty-five percent (10 out of 18) of the pre-AIDS isolates were serotype B, 28% were serotype A, 5% were serotype D, and an unexpected 11% (2 out of 18) were serotype C. These are the first to be recorded in Asia. In contrast, among the 169 clinical isolates obtained between January 1993 and March 1995 (AIDS epidemic), serotype A was outstandingly predominant-93% (157 out of 169), serotype B was relatively low (3.6%) and both serotypes D and AD were 1.8%. The pattern of serotypes of the 59 isolates from known HIV-positive patients was closely similar to the total isolates during the AIDS epidemic. In determining the varieties of C. neoformans by CGB, only 1 of the 187 isolates gave a false reaction. On the basis of our findings, we believe that in the pre-AIDS era either C. neoformans var. gattii serorype B or serotype C were the common causative agents of cryptococcosis in Thailand. The advent of AIDS changed the pattern of serotypes with serotype A becoming predominant as has been reported world wide.     

Successful treatment of antifungal- and cryotherapy-resistant subcutaneous hyalohyphomycosis in an immunocompetent case with topical 5% imiquimod cream

Hyalohyphomycosis is an unusual opportunistic mycotic infection where the tissue morphology of the causative organism is mycelial. Etiological agents, which are not responsible for the otherwise-named infections like aspergillosis, are the species of non-dematiaceous hyaline hyphomycetes including Penicillium, Paecilomyces, Acremonium (formerly known Cephalosporium), Beauveria, Fusarium, and Scopulariopsis. Several cases of Acremonium infection have been described in immunocompromised patients; however it can cause invasive disease in an immunocompetent person very rarely. Optimum therapy of Acremonium infection is unclear because of the limited number of reported cases and conflicting results of therapies. Imiquimod, an imidazoquinoline with potent antiviral, antitumor and immunoregulatory properties, is currently approved for the topical treatment of external anogenital warts and actinic keratosis. Imiquimod has also been found to be effective for other virus-associated dermatologic lesions, including common and flat warts, molluscum contagiosum, and herpes simplex virus type-2 as well as for some cases of cutaneous leishmaniasis. We report herein, for the first time, a case of unusually recalcitrant hyalohyphomycosis of the face due to Acremonium strictum successfully treated with topical 5% imiquimod in an immunocompetent patient, who had failed to respond to various antifungals, including itraconazole, and cryotherapy.