[Disseminated cryptococosis in renal transplant recipient]

The incidence of cryptococosis ranges from 0.4-5.8% in renal transplant. Meningitis is the principal clinical manifestation, frequently with a subacute curse. In renal transplantation recipients, disseminated cryptococcosis appears as the more frequent presentation. We report a case of a 32 years old woman renal transplant recipient who presents altered mental status, headache and tremor during the month before her assessment to our hospital. Microbiological study was performed in cerebrospinal fluid and cryptococcus was isolated. She was treated with amphotericin B and 5 flucytosine. She developed refractory increased intracranial pressure and a lumboperitoneal derivation was necessary. Cryptococcosis must be considered as cause of meningitis in patients with renal transplant. The early diagnosis and treatment are fundamental due to high mortality of this pathology.

[A case of primary pulmonary cryptococcosis showing lobar pneumonia on chest X-ray]

A 36-year-old male who had been in good health visited our hospital because of fever, productive cough and lobar pneumonia of the right lower lobe. Bronchoscopic examination revealed pulmonary cryptococcosis. After the initiation of fluconazole the pneumonia started to improve, however, it was aggravated after the discontinuation of fluconazole because of liver dysfunction induced by it. The pulmonary cryptococcosis improved by lobectomy of the right lower lobe. There have been few reports of lobar pneumonia caused by primary pulmonary cryptococcosis. We report this case with fourteen other cases of primary pulmonary cryptococcosis which have been experienced in our hospital.

[A case of pulmonary aspergillosis with bone invasion and destruction in an AIDS patient]

A 59-year-old HIV-infected man who had been treated for pulmonary cryptococcosis in another hospital was suffering from pulmonary tuberculosis. He was admitted to our hospital for treatment of tuberculosis. The chest radiograph on admission showed a large cavity in the left lower lung field. Chest CT showed a mass like a fungus ball in the cavity. Pulmonary aspergillosis was diagnosed from the sputum mycology and serum immunoprecipitins. During the treatment of pulmonary tuberculosis and cryptococcosis, thickening of the wall of the cavity was seen together with adjacent bone destruction. In an autopsy, Aspergillus spp. Were found to have invaded the bone tissue and caused bone destruction. Pulmonary aspergillosis in an AIDS patient is infrequent, and is rare in additional association with bone invasion and destruction.

Cryptococcal cellulitis in a patient on prednisone monotherapy for myasthenia gravis

The development of cutaneous cryptococcosis is extremely rare in the human immunodeficiency virus-negative population. The cutaneous manifestations vary greatly, with the rarest presenting as cellulitis. We report a unique case of a 64-year-old woman who had been on prednisone monotherapy for the treatment of myasthenia gravis and subsequently developed cryptococcal cellulitis. This case provides an opportunity to discuss the importance of including cryptococcal cellulitis in the differential diagnosis of cellulitis in a patient on low-dose prednisone who is not responding to empiric antibiotic therapy. Early recognition is crucial as cutaneous manifestations are usually the first sign of disseminated cryptococcosis.

Cryptococcemia. An analysis of 28 cases with emphasis on the clinical outcome and its etiologic agent

Clinical protocols of 28 cases of cryptococcemia studied between April 1995 and November 2002 were reviewed. The varieties of Cryptococcus neorformans, the underlying disease, and the severity and outcome of the disease were emphasized. Most patients were immunossupressed (89.3% with AIDS) and Cryptococcus neoformans var. grubii was the main recovered variety (92.8%). Regardless of antifungal treatment, in-hospital mortality was 41% strongly associated with APACHE II score, >14 (p<0.01).

Primary Cutaneous Cryptococcosis in a Lung Transplant Recipient

Cryptococcal skin lesions are found in 10 to 15% of patients with disseminated cryptococcosis. Primary skin inoculation by Cryptococcus neoformans is rare but has been reported. We report the first known case of primary cutaneous cryptococcosis in a lung transplant recipient. Our patient, a 57-year-old man, underwent left single-lung transplantation and presented with a nonhealing ulcer 50 months later. Skin histopathology and culture confirmed C. neoformans. Serum and cerebrospinal fluid cryptococcal antigen tests were negative. The lesion healed after treatment with fluconazole. To date, disseminated disease is not evident. Primary cutaneous cryptococcosis has been reported in kidney and liver recipients but not in lung transplantation recipients. Nonhealing ulcers in immunocompromised patients mandate aggressive diagnostic procedures. Differential diagnosis of these cutaneous lesions should consider fungi, including C. neoformans.

Primary cutaneous cryptococcosis in an elderly man

Cryptococcus neoformans is an opportunistic yeast with a worldwide distribution. Although well recognized as a cause of cutaneous disease in immunocompromised patients, this rarely occurs in healthy hosts. In this article, we present the case of a farmer who developed cutaneous cryptococcosis at the site of an injury he sustained while cleaning out his barn. Despite an extensive work-up, no evidence of disseminated disease or underlying immunosuppression was found. The patient recovered completely several weeks after beginning treatment with oral fluconazole.

CNLAC1 is required for extrapulmonary dissemination of Cryptococcus neoformans but not pulmonary persistence

The pathogenic yeast Cryptococcus neoformans produces a laccase enzyme (CNLAC1), which catalyzes the synthesis of melanin in the presence of phenolic compounds. A number of genes have been implicated in the regulation of laccase and melanization, including IPC1, GPA1, MET3, and STE12. Albino mutants derived from random mutagenesis techniques may contain mutations in genes that regulate multiple virulence factors, including CNLAC1. The goal of our study is to investigate the role of CNLAC1 in virulence and evasion of pulmonary host defenses after infection via the respiratory tract. Using a set of congenic laccase-positive (2E-TUC-4) and laccase-deficient (2E-TU-4) strains, we found that both strains are avirulent at a lower dose (10(4) CFU/mouse) in mice. After the infectious dose was increased to 10(6) CFU/mouse, 70% mortality was observed in mice infected with 2E-TUC-4 compared to no mortality in mice infected with 2E-TU-4 at day 30 postinfection. This observation confirms the requirement for CNLAC1 in virulence. Interestingly, we observed no differences between the two strains in pulmonary growth or in elicitation of cellular immune responses in the lung. The only measurable defect of 2E-TU-4 was in dissemination to extrapulmonary sites. To examine the role of CNLAC1 in dissemination, mice were infected intravenously. By week 3 postinfection, equal numbers of strains 2E-TUC-4 and 2E-TU-4 were recovered from the brain and spleen. This observation indicates that CNLAC1 facilitates escape from the lung, but not growth in the lungs or brain, and suggests a novel role for CNLAC1 in virulence during an infection aquired via the respiratory tract.

[A case of secondary pulmonary cryptococcosis complicating diabetes mellitus]

In this case, a 65-year-old man complained of fever and productive cough while being treated for diabetes mellitus at the outpatient clinic. His chest CT scan revealed multiple infiltrative lesions in both the right and left lower pulmonary lobes. He was therefore given an antibiotic on suspicion of having bacterial pneumonia, and he also received nutritional instruction in relation to diabetes mellitus, and remission resulted. However, he could not maintain sufficient glycemic control thereafter, and his pulmonary lesions persisted. Because his lesions changed into cavitied multiple nodular lesions, as seen on a chest CT scan, a transbronchial lung biopsy was performed. Histopathological examination of the biopsy specimen demonstrated Cryptococcus organisms, and the Cryptococcus antigen titer was high, which led to a diagnosis of pulmonary cryptococcosis. After oral treatment with fluconazole for 1 year and 4 months, only a small nodule in the right lower lobe and a funicular lesion in the left lower lobe remained on a chest CT scan, and the patient had neither subjective symptoms nor evidence of inflammation, although he still had a positive antigen titer for Cryptococcus. Thus, the treatment was terminated. Improvement of the clinical symptoms and of the laboratory and radiological findings demonstrated the therapeutic efficacy of this treatment.

Mucosal and Systemic Fungal Infections in Patients with AIDS

In countries where highly active antiretroviral therapy (HAART) is widely available, a decrease in the incidence of fungal infections has been observed in the last 5 years compared with countries that cannot afford this treatment. Even refractory fungal infections may be controlled when HAART is given to patients, and end-stage AIDS infections, such as aspergillosis, are now only infrequently seen. In contrast, fungal infections in certain regions, such as penicilliosis in Southeast Asia or cryptococcosis in Sub-Saharan Africa, are a growing problem. Antifungal therapy for documented infections has not changed very much during recent years; however, new drugs such as caspofungin and voriconazole may be more effective in the treatment of opportunistic fungal infections, in particular, those involving resistant organisms. Secondary antifungal prophylaxis for many opportunistic pathogens can now be temporarily or even permanently discontinued in many HIV-positive patients who have a marked improvement in immune function parameters, such as CD4(+) cell counts, after initiation of HAART. The link between effective virustatic control of HIV infection and a decreasing incidence of fungal infections has been recognised; and so, despite the availability of very effective new antifungal drugs, the cornerstone of treatment and prevention of opportunistic fungal infections in patients with HIV infection is effective antiretroviral therapy including protease inhibitors.

[A case of pulmonary cryptococcosis with multiple nodular shadows under treatment of bronchiolitis obliterans with organizing pneumonia (BOOP)]

A 66 year-old man was introduced to our hospital because of multiple infiltrative pulmonary shadows on February, 2001. We diagnosed bronchiolitis obliterans with organizing pneumonia (BOOP) from the clinical and bronchoalveolar lavage fluid (BALF) findings, and initiated oral steroid therapy. Since the abnormal chest shadows disappeared, the dose of steroid was decreased and maintained at 10 mg/day. In August 2001, multiple infiltrative shadows returned, and we therefore increased the steroid dose to 30 mg/day. The expanding infiltrative shadows were then joined by new multiple nodular shadows. The bronchioalveolar lavage fluid revealed small bodies of cryptococcus species. A positive result for anti-cryptococcus antigen was also obtained from the serum. We then diagnosed pulmonary cryptococcosis without meningitis. Therapy was started with anti-mycotic agents including amphotericin-B, flucytosine and fluconazole, which proved successful. This case of opportunistic cryptococcus infection in an immunocompromized patient, which responded to anti-mycotic therapy, is reported.

Role of alternative oxidase gene in pathogenesis of Cryptococcus neoformans

We identified a homologue of the alternative oxidase gene in a screen to identify genes that are preferentially transcribed in response to a shift to 37 degrees C in the human-pathogenic yeast Cryptococcus neoformans. Alternative oxidases are nucleus-encoded mitochondrial proteins that have two putative roles: they can function in parallel with the classic cytochrome oxidative pathway to produce ATP, and they may counter oxidative stress within the mitochondria. The C. neoformans alternative oxidase gene (AOX1) was found to exist as a single copy in the genome, and it encodes a putative protein of 401 amino acids. An aox1 mutant strain was created using targeted gene disruption, and the mutant strain was reconstituted to wild type using a full-length AOX1. Compared to both the wild-type and reconstituted strains, the aox1 mutant strain was not temperature sensitive but did have significant impairment of both respiration and growth when treated with inhibitors of the classic cytochrome oxidative pathway. The aox1 mutant strain was also found to be more sensitive to the oxidative stressor tert-butyl hydroperoxide. The aox1 mutant strain was significantly less virulent than both the wild type and the reconstituted strain in the murine inhalational model, and it also had significantly impaired growth within a macrophage-like cell line. These data demonstrate that the alternative oxidase of C. neoformans can make a significant contribution to metabolism, has a role in the yeast's defense against exogenous oxidative stress, and contributes to the virulence composite of this organism, possibly by improving survival within phagocytic cells.

Cryptococcus neoformans virulence is enhanced after growth in the genetically malleable host Dictyostelium discoideum

Cryptococcus neoformans is an encapsulated, environmental fungus that can cause life-threatening meningitis. Pathogenicity of C. neoformans for macrophages and vertebrate hosts may be a mechanism selected in evolution for protection against environmental predators. In this study, we investigated whether Dictyostelium discoideum could serve as an alternate host for C. neoformans. D. discoideum has a defined genetic system which provides significant advantages for the study of fungus-amoeba interactions. Our results show that D. discoideum is susceptible to infection with C. neoformans and that the interactions are similar to those described previously for this fungus with macrophages and Acanthamoeba castellanii. Acapsular C. neoformans cells did not replicate when coincubated with D. discoideum. However, incubation of acapsular C. neoformans with D. discoideum mutants defective in myosin VII synthesis resulted in infection, validating the concept that avirulent organisms can be virulent in impaired hosts even at the unicellular level. Phagocytosis of C. neoformans by D. discoideum could be inhibited with capsule-specific antibodies and various sugars. Passage of an encapsulated C. neoformans strain through D. discoideum cultures increased virulence and was accompanied by larger capsules and faster time to melanization. These results add to the evidence implicating soil ameboid predators as important factors for the maintenance of C. neoformans virulence in the environment and suggest that D. discoideum promises to be an extremely useful system for studying the interaction of C. neoformans with phagocytic cells.

Experimental murine cryptococcal infection results in contamination of bedding with Cryptococcus neoformans

Cryptococcus neoformans is a fungal pathogen that survives in diverse environments. To determine whether cages of mice infected with C. neoformans posed an infection risk to animal caregivers, we investigated whether the fungus could be isolated from the bedding or stool of mice infected by intratracheal (i.t.), intravenous (i.v.), or intraperitoneal (i.p.) routes. The bedding of mice infected i.t. was contaminated with C. neoformans. In contrast, no contamination of bedding with C. neoformans was detected in cages of mice infected i.v. or i.p. C. neoformans was not isolated from murine feces. The C. neoformans strain recovered from bedding material was indistinguishable from the infecting strain by biochemical and molecular techniques. This result suggests that precautions may be warranted when disposing bedding from cages that housed mice with pulmonary C. neoformans infection.

Role of PLB1 in pulmonary inflammation and cryptococcal eicosanoid production

Cryptococcal phospholipase (PLB1) is a secreted enzyme with lysophospholipase hydrolase and lysophospholipase transacylase activities. To investigate the role of PLB1 in the evasion of host immune responses, we characterized pulmonary immune responses to the parental (H99), the plb1 mutant, and the plb1(rec) reconstituted mutant strains of Cryptococcus neoformans in mice. PLB1 was required for virulence during infection acquired via the respiratory tract. Mice infected with either H99 or the plb1(rec) strain generated a nonprotective inflammatory response with subsequent eosinophilia, while mice infected with the plb1 mutant generated a protective immune response that controlled the infection. Because PLB1 is believed to facilitate virulence through host cell lysis, we examined the interaction of these strains with macrophages. The plb1(rec) mutant exhibited decreased survival during coculture with macrophages. One factor which may be involved in the survival of yeast in the presence of macrophages is fungal eicosanoid production. Host eicosanoids have been shown to down-modulate macrophage functions. plb1 exhibited a defect in eicosanoid production derived from exogenous arachidonoyl-phosphatidylcholine, suggesting that PLB1 is required for the release of arachidonic acid from phospholipids. These data suggest that cryptococcal PLB1 may act as a virulence factor by enhancing the ability to survive macrophage antifungal defenses, possibly by facilitating fungal eicosanoid production.

Immune reconstitution cryptococcosis after initiation of successful highly active antiretroviral therapy

Five of 10 patients who commenced successful highly active antiretroviral therapy (HAART) for infection with human immunodeficiency virus type 1 (HIV-1) concurrent with or soon after a diagnosis of cryptococcal infection experienced clinical events characterized by sterile inflammation. Two patients developed aseptic meningitis with elevated intracranial pressure, 1 developed intrathoracic lyphadenopathy with hypercalcemia, 1 developed cavitary pneumonia at the site of a cryptococcal nodule, and 1 developed a supraclavicular abscess. These events occurred 2-11 months after initiation of HAART. For 3 patients, biopsy demonstrated findings atypical for acquired immunodeficiency syndrome-associated cryptococcosis. Results of fungal cultures were negative for all 5 patients, and cryptococcal antigen levels had declined markedly in 4 patients. The timing and clinical features of and biopsy findings for these cases of cryptococcosis suggest the existence of a paradoxical reaction to Cryptococcus infection that occurs in the context of HIV immune restoration.

Systemic fungal infections after renal transplantation

In a retrospective evaluation, the incidence of systemic fungal infections (SFIs) in 296 kidney graft recipients admitted to our center between 1986 and 1999 was found to be 4%. Eighteen percent of 28 recipients transplanted in India and 8% of 12 recipients transplanted in Russia developed SFI. In contrast, SFI was encountered in only 2% of recipients transplanted at our center. The median time of diagnosis of SFI was 5 months after transplantation. The lungs and central nervous system were the most frequently affected sites. The most common etiologic agent was Aspergillus fumigatus (n = 7) but Candida spp. (n = 1), Rhizopus spp. (n = 1) and Cryptococcus neoformans (n = 1) were also encountered. In 2 patients, 2 different pathogens were isolated at the same time: A. fumigatus and Rhizopus spp. in 1 patient and Candida spp. and A. fumigatus in another. In order to determine predisposing factors for SFI, patients admitted immediately before and after those with SFI were used as controls: long-term hospitalization, long-term antibiotic use and post-transplant diabetes mellitus were found to be predisposing factors. Eight patients were treated with antifungal drugs and a good response to liposomal amphotericin B therapy was obtained in 3/5. Nine patients (75%) with SFI died. As SFIs are associated with a high mortality rate in renal transplant recipients, antifungal therapy, especially with liposomal amphotericin B, should be started whenever fungal infection is suspected, even before the results of microbiologic and/or histologic examinations are known.

Cryptococcosis

Cryptococcus neoformans has risen to a worldwide highly recognizable major opportunistic pathogen with deadly consequences. It has become a model fungus to study a variety of paradigms in the host-fungus relationships. Genomic studies are advancing knowledge on its evolution and dissecting its virulence composite. Studies designed to understand host immunology to this fungus are leading to development of active and passive prevention and therapeutic strategies. This article collates and analyzes both new and old knowledge about the pathogen to help frame the meaning of human cryptococcosis as it starts to evolve in the new millennium.

European Confederation of Medical Mycology (ECMM) prospective survey of cryptococcosis: report from Italy

Italy is one of the countries participating in a prospective epidemiological survey of cryptococcosis set up in July 1997 by the European Confederation of Medical Mycology (ECMM). Over a 30-month period 156 cases, all caused by Cryptococcus neoformans var. neoformans, were reported by 29 hospitals in 9 regions. An ECMM questionnaire was used to report the clinical presentation and the diagnostic and treatment approach used. Cryptococcosis was associated with HIV infection in 147 cases and was considered indicative of AIDS in 65%. The estimated incidence in the Lombardy region was 0.85/100 in the AIDS population. One isolate from each of 129 patients was serotyped and genotyped. PCR fingerprinting using the primer (GACA)4 proved to be a more reproducible typing method than the slide agglutination test. Genotypes VN1 (serotype D), VN6 (serotype A) and VN3-VN4 (serotype AD hybrid strains) occurred in Italy at similar levels nationwide, but VN1 (D) was prevalent in the North. In vitro resistance to antifungals was uncommon.

Relationship of the glyoxylate pathway to the pathogenesis of Cryptococcus neoformans

Functional genomics has become a major focus in the study of microbial pathogenesis. This study used a functional genomic tool, differential display reverse transcription-PCR, to identify a transcriptional profile of Cryptococcus neoformans cells as they produced meningitis in an immunosuppressed host. This serial global gene expression during infection allowed for the identification of up- and down-regulated genes during infection. During this profiling, a single gene for the enzyme isocitrate lyase (ICL1) was found to be up regulated at 1 week of infection in a rabbit meningitis model and during a time of maximum host cellular response. The finding suggested that this enzyme and the glyoxylate shunt pathway are important to this yeast's energy production during infection. However, site-directed icl1 mutants had no apparent virulence defect in two animal models and no growth defect within macrophages. These observations suggest that although the yeast responded to a certain environmental cue(s) by an increase in ICL1 expression during infection, this gene was not necessary for progression of a C. neoformans infection. Compounds that specifically target only ICL1 are unlikely to cripple C. neoformans growth in vivo.

Saprophytic fungal infections and complications involving the bronchial anastomosis following human lung transplantation

STUDY OBJECTIVE

To demonstrate an association between saprophytic fungal infections occurring at the bronchial anastomosis (BA) and the development of additional complications arising at this site.

DESIGN

Retrospective review.

SETTING

University lung transplant center.

MATERIALS AND METHODS

Review of all single-lung and double-lung transplant (LTX) recipients who underwent transplantation between June 1993 and December 2000. All recipients were subjected to surveillance bronchoscopy with biopsy at predetermined intervals and when clinically indicated. Bronchial wash fluid and biopsy material were examined using appropriate fungal stains and culture techniques. An infection was defined when fungal organisms were identified in tissue specimens.

RESULTS

Fifteen saprophytic fungal infections involving the BA were identified in 61 LTX recipients (24.6%) who survived a minimum of 75 days post-transplantation. Infections were attributed to Aspergillus sp (n = 9), Candida sp (n = 2), Torulopsis sp (n = 1), and mixed flora (ie, Penicillium + Candida, two patients; and Aspergillus + Candida, one patient). Saprophytic fungal infections occurred by a median of postoperative day 35 (range, 13 to 159 days). Airway complications involving the BA ultimately developed in 11 of 61 recipients (18%). These complications included symptomatic bronchial stenosis (nine patients), bronchomalacia (one patient), and fatal hemorrhage (one patient). Bronchial complications arose in 7 of 15 recipients (46.7%) with saprophytic fungal infections of the BA in contrast to 4 of 46 (8.7%) without infections (p = 0.003, Fisher exact test). Also demonstrated was a positive correlation between anastomotic infections and bronchial complications (Phi coefficient = 0.43; p = 0.001), while logistic regression analysis revealed that the absence of anastomotic infections predicted the absence of such complications (p = 0.002). The risk of developing an additional complication following an anastomotic infection in patients with infections was five times that of those recipients without an infection (relative risk, 5.36; 95% confidence interval [CI], 1.82 to 15.79). The odds in favor of a bronchial complication following an infection were eight times greater than in those recipients without infection (odds ratio, 8.31; 95% CI, 1.96 to 35.16).

CONCLUSIONS

Following LTX, saprophytic fungal infections of the BA are associated with serious airway complications.

Fungemia in a cancer patient caused by fluconazole-resistant Cryptococcus laurentii

We report the recent isolation of Cryptococcus laurentii from the blood of a patient given the diagnosis of ganglioneuroblastoma. The organism was identified using physiological and molecular characteristics, including morphology, carbohydrate and nitrate assimilation, urease activity, inability to form melanin on appropriate media, positive staining with diazonium blue B and sequence analysis of the D1/D2 domain of 26S ribosomal DNA. The isolate was resistant to fluconazole and 5-fluorocytosine using both the Etest and a broth microdilution assay. Repeated recovery of the organism from different blood cultures, and the patient's good response to treatment with amphotericin B support its etiological role. C. laurentii has rarely been implicated as a cause of clinically significant infections. The identity of reported isolates has not always been adequately documented, and some appear to have been isolated from lesions caused by Cryptococcus neoformans, emphasizing the true rarity of disease due to this fungus.

[Physiopathology of meningoencephalitis caused by Cryptococcus neoformans]

Cryptococcus neoformans is an encapsulated yeast mainly responsible for meningoencephalitis, especially in AIDS patients. Recent observations using an experimental model of systemic cryptococcosis that mimics the human infection have reinforced the knowledge on the pathogenesis of cryptococcosis. Cryptococcosis may occur several years after inhalation of infecting particles from the environment. A stage of fungemia that reflects the dissemination of infection usually precedes the development of meningoencephalitis. The capsule mainly composed of glucuronoxylomannan constitutes the main virulence factor of C. neoformans. It has several deleterious effects including the inhibition of the host immune responses. The central nervous system involvement differs between AIDS patients and HIV-negative patients. In AIDS patients, histological studies of the brain show numerous cryptococci without significant inflammatory cell response. In other immunodepressed hosts, a granulomatous inflammation containing few yeasts is usually seen. This may reflect an altered local immunological defect against C. neoformans in AIDS patients with cryptococcosis.