[Guidelines in cryptococcosis--2008]

Association between neuroimaging and clinical outcomes in individuals with central nervous system cryptococcosis

BACKGROUND

The radiological manifestations of central nervous system (CNS) cryptococcosis are diverse and often subtle. There is heterogeneity on how different neuroimaging patterns impact prognosis. This study aims to assess the association between the neuroimaging and clinical outcomes of CNS cryptococcosis.

METHODS

All patients with CNS cryptococcosis between July 2017 and April 2023 who underwent brain magnetic resonance imaging (MRI) were included. The primary outcome was mortality during hospitalisation. Secondary outcomes were readmission, ventricular shunting, duration of hospitalisation and time to the first negative cerebrospinal fluid culture. We compared the outcomes for each of the five main radiological findings on the brain MRI scan.

RESULTS

We included 46 proven CNS cryptococcosis cases. The two main comorbidity groups were HIV infection (20, 43%) and solid organ transplantation (10, 22%), respectively. Thirty-nine patients exhibited at least one radiological abnormality (85%), with the most common being meningeal enhancement (34, 74%). The mortality rates occurred at 11% (5/46) during hospitalisation. We found no significant disparities in mortality related to distinct radiological patterns. The presence of pseudocysts was significantly associated with the need for readmission (p = .027). The ventricular shunting was significantly associated with the presence of pseudocysts (p = .005) and hydrocephalus (p = .044).

CONCLUSION

In this study, there is no association between brain MRI findings and mortality. Larger studies are needed to evaluate this important issue.

Modeling and Simulation as a Tool to Assess Voriconazole Exposure in the Central Nervous System

Voriconazole is a triazole antifungal used empirically for the treatment of complicated meningitis associated with Cryptococcus neoformans. Biopsy studies show that the drug exhibits adequate brain penetration although levels of cerebral spinal fluid (CSF) are highly variable. Considering that CSF is one of the main surrogates for CNS exposure, the present work proposed the building of a population pharmacokinetic modeling (popPK) model able to describing the exposure achieved by voriconazole in the plasma, interstitial cerebral fluid and CSF of healthy and infected rats. The developed popPK model was described by four compartments, including total plasma, free brain and total CSF concentrations. The following PK parameters were determined: K_m = 4.76 mg/L, V_max = 1.06 mg/h, Q₁ = 2.69 L, Q_in = 0.81 h^-1 and Q_out = 0.63 h^-1. Infection was a covariate in the Michaelis-Menten constant (K_m) and intercompartmental clearance from the brain tissue compartment to central compartment (Q_out). Simulations performed with the popPK model to determine the probability of reaching the therapeutic target of fAUC > MIC showed that VRC has sufficient tissue exposure in the interstitial fluid and in the CSF for the treatment of fungal infections in these tissues at prevalent minimum inhibitory concentrations.

Antifungal activity of liriodenine on clinical strains of Cryptococcus neoformans and Cryptococcus gattii species complexes

Background:

Cryptoccocal meningitis continues to present high incidence among AIDS patients. The treatment of choice is the synergistic combination of flucytosine (5-FC) with amphotericin B deoxycholate (AmBd) or its lipid formulations. However, 5-FC is unavailable in many countries and AmB demands hospitalization. The combination of AmB with the fungistatic fluconazole (FLC) or the use of high FLC daily doses alone became the choice. Nonetheless, sterilization of cerebrospinal fluid is delayed with FLC monotherapy, mainly with high fungal burden. These findings suggest the search for new antifungal compounds, such as liriodenine.

Methods:

Liriodenine antifungal activity was evaluated by three procedures: determining the minimum inhibitory concentration (MIC) on 30 strains of the Cryptococcus neoformans (C. neoformans) complex and 30 of the Cryptococcus gattii (C. gattii) complex, using EUCAST methodology and amphotericin B deoxycholate as control; performing the time-kill methodology in two strains of the C. neoformans complex and one of the C. gattii complex; and injury to cryptococcal cells, evaluated by transmission electron microscopy (TEM). Liriodenine absorption and safety at 0.75 and 1.50 mg.kg^-1 doses were evaluated in BALB/c mice.

Results:

Liriodenine MICs ranged from 3.9 to 62.5 μg.mL^-1 for both species complexes, with no differences between them. Time-kill methodology confirmed its concentration-dependent fungicidal effect, killing all the strains below the limit of detection (33 CFU.mL^-1) at the highest liriodenine concentration (32-fold MIC), with predominant activity during the first 48 hours. Liriodenine induced severe Cryptococcus alterations - cytoplasm with intense rarefaction and/or degradation, injury of organelles, and presence of vacuoles. Liriodenine was better absorbed at lower doses, with no histopathological alterations on the digestive tract.

Conclusion:

The fungicidal activity confirmed by time-kill methodology, the intense Cryptococcus injury observed by TEM, the absorption after gavage administration, and the safety at the tested doses indicate that the liriodenine molecule is a promising drug lead for development of anticryptococcal agents.

Cryptococcus spp. and Cryptococcosis: focusing on the infection in Brazil

Cryptococcosis is a global fungal infection caused by the Cryptococcus neoformans/Cryptococcus gattii yeast complex. This infection is acquired by inhalation of propagules such as basidiospores or dry yeast, initially causing lung infections with the possibility of progressing to the meninges. This infection mainly affects immunocompromised HIV and transplant patients; however, immunocompetent patients can also be affected. This review proposes to evaluate cryptococcosis focusing on studies of this mycosis in Brazilian territory; moreover, recent advances in the understanding of its virulence mechanism, animal models in research are also assessed. For this, literature review as realized in PubMed, Scielo, and Brazilian legislation. In Brazil, cryptococcosis has been identified as one of the most lethal fungal infections among HIV patients and C. neoformans VNI and C. gattii VGII are the most prevalent genotypes. Moreover, different clinical settings published in Brazil were described. As in other countries, cryptococcosis is difficult to treat due to a limited therapeutic arsenal, which is highly toxic and costly. The presence of a polysaccharide capsule, thermo-tolerance, production of melanin, biofilm formation, mechanisms for iron use, and morphological alterations is an important virulence mechanism of these yeasts. The introduction of cryptococcosis as a compulsory notification disease could improve data regarding incidence and help in the management of these infections.

Evaluation of IFN-γ secretion after stimulation with C. neoformans and C. gattii antigens in individuals with frequent exposure to the fungus

In this study we produced antigenic extracts from prototypical strains of C. neoformans (VNI-VNIV) and C. gattii (VGI-VGIV) and tested IFN-γ secretion by Elispot. Antigens from the eight Cryptococcus molecular types (VNI -VNIV and VGI - VGIV) were obtained after capsule reduction. IFN-γ secretion by Elispot method were stimulated with C. neoformans and C. gattii antigens. Peripheral blood mononuclear cells of fourteen healthy control subjects, being: five ecotourists, two mycologists, three poultry keepers, and four individuals without reports of exposure to the fungus. We observed a significant increase in IFN-γ secretion in the group of ecotourists, mycologists and bird keepers in relation to the group of individuals without reports of occupational exposures to these agents. Our results suggest the significant increase in IFN-γ secretion may be related to the continuous exposure of these groups of individuals to the fungus, as well as to the specific antigen memory immune response developed during exposure to Cryptococcus.

Cost-Effectiveness Analysis of the Implementation of Cryptococcal Antigen Lateral Flow Assay for the Diagnosis of Cryptococcal Meningitis in Symptomatic People Living With Human Immunodeficiency Virus in Brazil

OBJECTIVES

Cryptococcal meningitis constitutes a significant source of mortality in the developing world. Annually, approximately 625 000 deaths occur worldwide among patients with human immunodeficiency virus (HIV) infection. This study aims to assess the cost-effectiveness of implementing cryptococcal antigen lateral flow assay (CRAG-LFA) screening in Brazil compared with the current practice.

METHODS

An economic evaluation using a Monte Carlo microsimulation was conducted, considering the perspective of the Brazilian Public Health System, to calculate the cost-effectiveness of 4 diagnosis tests: (1) CRAG-LFA, (2) the cryptococcal antigen latex agglutination (CRAG-LA) test, (3) India ink, and (4) nontracking as a baseline. The time horizon comprised 1 year for the intervention and 5 years for the budgetary impact analysis. Two primary effectiveness outcomes were considered: years of life and quality-adjusted life-years.

RESULTS

CRAG-LFA has extended dominance vis à vis CRAG-LA and India ink. CRAG-LFA would cost $418.46 more than CRAG-LA for the treatment of each symptomatic patient living with HIV, with an incremental cost effectiveness ratio of $2478.75/quality-adjusted life year. The budgetary impact analysis estimated that the incorporation of CRAG-LFA would have an additional cost of $1 959 236.50 in 5 years.

CONCLUSIONS

These findings suggest that, for patients living with HIV in the Brazilian Public Health System, the adoption of CRAG-LFA screening is cost-effective compared with the use of CRAG-LA and India ink. It represents an opportunity to prevent cryptococcal meningitis and its mortality in Brazil.

Cryptococcus liquefaciens isolated from the hand of a healthcare professional in a neonatal intensive care unit

Fungal infections are responsible for high morbidity and mortality in neonatal patients, especially in premature newborns. Infections in neonates caused by Cryptococcus spp. are rare, but it has occurred in an immunocompromised population. This study aims to describe the isolation of Cryptococcus liquefaciens from the hands of a health professional in a neonatal intensive care unit, and to evaluate the production of biofilm and virulence factors and susceptibility to antifungals. Antifungal susceptibility tests were performed according to Clinical and Laboratory Standard Institute document M27-A3. Thermotolerance virulence factors and DNase, phospholipase, proteinase, and hemolytic activities were verified through phenotypic tests; biofilm was evaluated by determining the metabolic activity and biomass. The isolate did not produce any of the tested enzymes and was susceptible to all antifungals (amphotericin B, fluconazole, and micafungin). The growth at 37 °C was very weak; however, the isolate showed a strong biomass production and low metabolic activity. This is the first report of C. liquefaciens isolated from the hands of a health professional. The isolate did not express any of the studied virulence factors in vitro, except for the low growth at 37 °C in the first 48 h, and the strong production of biofilm biomass. Cryptococcus liquefaciens can remain in the environment for a long time and is a human pathogen because it tolerates temperature variations. This report draws attention to the circulation of rare species in critical locations, information that may help in a fast and correct diagnosis and, consequently, implementation of an appropriate treatment.

Cost-effectiveness analysis and budgetary impact of the Cryptococcal Antigen Lateral Flow Assay (CRAG-LFA) implementation for the screening and diagnosis of cryptococcosis in asymptomatic people living with HIV in Brazil

Cryptococcal infection is a frequent cause of mortality in Brazilian HIV-infected patients. The present study aimed to evaluate the cost-effectiveness and budgetary impact of four cryptococcosis screening strategies in HIV-infected patients with CD4+ ≤ 200 cells/mm³, in Brazil. A Monte Carlo microsimulation was used to compare the following diagnostic tests: a systematic serum cryptococcal antigen (CRAG) screening with latex agglutination (CRAG-LA), a lateral flow immunochromatographic test (CRAG-LFA), India ink staining and no intervention. The rationale was that of the Unified Health System (SUS), and the time horizon was of one year for the intervention and of five years for the budgetary impact analysis (BIA). The effectiveness outcomes were years of life and years of life adjusted for quality (QALY). The cost-effectiveness analysis showed that the two cryptococcal antigen tests were cost-effective, presenting with superior results in comparison with India ink and no screening. CRAG-LFA, compared to CRAG-LA, has an incremental cost of US$0.25 and an incremental cost-effectiveness ratio of US$73.36 (considering the US dollar equal to 5 reais, the Brazilian current money). The probabilistic sensitivity analysis between CRAG-LFA and CRAG-LA, despite showing a high agreement between the two tests, indicated the superiority of CRAG-LFA. The BIA estimated that the incorporation of CRAG-LFA would have an additional cost of approximately U$S 10.4 million dollars in five years. These findings suggest that, for the group of studied patients, the adoption of CRAG-LFA and CRAG-LA are cost-effective, while the India ink test and no intervention are less effective strategies. The BIA showed that using the CRAG-LFA test for people living with HIV (PLHIV) with CD4+ ≤ 200 cells/mm³ could reduce costs for the Brazilian Unified Health System (SUS).

Cryptococcal peritonitis in patients on the liver transplant waitlist: Reporting two cases with opposite outcomes

Cryptococcus neoformans is rarely associated with peritonitis in cirrhotic patients; nevertheless, it has a high mortality rate. Early diagnosis and prompt treatment may be the determining prognostic factors. This is a report of two patients awaiting a liver transplant who had opposite outcomes after the diagnosis of spontaneous cryptococcal peritonitis. In Patient 1, the fungal culture was positive in the blood and ascites. She had a poor evolution and died, which was likely caused by the delayed diagnosis and concomitant bacterial infections. In Patient 2, the fungus was found in the ascites, urine, and cerebrospinal fluid cultures. Antifungal treatment was effective. He underwent a liver transplant on the 83rd day of antifungal therapy and is still alive 1 year later. It is important to suspect fungal etiology when there is a lack of response to antibiotics in patients with decompensated cirrhosis and spontaneous peritonitis, and physicians must be aware of leukocyte count in the ascitic fluid, which is not so high in these cases. This report also emphasizes the need for the routine use of blood culture bottles for microbiological analysis of the ascitic fluid, as it was helpful to diagnose fungal peritonitis in both cases.

Antifungal activity of liriodenine on agents of systemic mycoses, with emphasis on the genus Paracoccidioides

BACKGROUND

Endemic systemic mycoses remain a health challenge, since these opportunistic diseases are increasingly infecting immunosuppressed patients. The simultaneous use of antifungal compounds and other drugs to treat infectious or non-infectious diseases has led to several interactions and undesirable effects. Thus, new antifungal compounds should be investigated. The present study aimed to evaluate the activity of liriodenine extracted from Annona macroprophyllata on agents of systemic mycoses, with emphasis on the genus Paracoccidioides.

METHODS

The minimum inhibitory concentration (MIC) and minimum fungicide concentration (MFC) were determined by the microdilution method. The cellular alterations caused by liriodenine on a standard P. brasiliensis (Pb18) strain were evaluated by transmission and scanning electron microscopy.

RESULTS

Liriodenine was effective only in 3 of the 8 strains of the genus Paracoccidioides and in the Histoplasma capsulatum strain, in a very low concentration (MIC of 1.95 μg.mL-1); on yeasts of Candida spp. (MIC of 125 to 250 μg.mL-1), including C. krusei (250 μg.mL-1), which has intrinsic resistance to fluconazole; and in Cryptococcus neoformans and Cryptococcus gattii (MIC of 62.5 μg.mL-1). However, liriodenine was not effective against Aspergillus fumigatus at the studied concentrations. Liriodenine exhibited fungicidal activity against all standard strains and clinical isolates that showed to be susceptible by in vitro tests. Electron microscopy revealed cytoplasmic alterations and damage to the cell wall of P. brasiliensis (Pb18).

CONCLUSION

Our results indicate that liriodenine is a promising fungicidal compound that should undergo further investigation with some chemical modifications.

Molecular typing, in vitro susceptibility and virulence of Cryptococcus neoformans/Cryptococcus gattii species complex clinical isolates from south-eastern Brazil

BACKGROUND

Cryptococcus neoformans/ Cryptococcus gattii species complex is composed of encapsulated yeast species that are causative agents of cryptococcosis. The characterisation of pathogenic Cryptococcus species provides useful data for epidemiological studies as well as the clinical diagnosis and treatment of patients.

OBJECTIVES

This study aimed to characterise the epidemiology, antifungal susceptibility and virulence of 72 clinical strains isolated from cryptococcosis cases between 2012 and 2017 in a tertiary reference hospital in south-eastern Brazil.

METHODS

Species and molecular types were molecularly assessed by PCR and PCR-restriction fragment length polymorphism (RFLP) of the URA5 gene. Antifungal susceptibility testing was performed according to the CLSI protocols. The virulence was studied in a Galleria mellonella infection model.

RESULTS

The most frequently isolated strain was C. neoformans molecular type VNI (61/72; 84.7%), although C. neoformans molecular type VNII (3/72; 4.2%) was also isolated. Additionally, C. deuterogattii molecular type VGII (8/72; 11.1%) was present, but most frequently from non-HIV-infected patients. Non-wild-type phenotype to the antifungals was observed in 26.4% (19/72) of the C. neoformans and C. deuterogattii clinical isolates, and the latter demonstrated higher MIC to fluconazole and itraconazole than C. neoformans clinical isolates. Finally, the virulence of C. neoformans and C. deuterogattii clinical isolates was diverse in G mellonella larvae and uncorrelated with the virulence factors of melanin and capsule.

CONCLUSIONS

The assessment of the spread of cryptococcal species and molecular types as well as the pattern of corresponding antifungal susceptibility and virulence aids in surveil the emergence of resistant strains, ensuring more accurate management of the cryptococcal infection.

Darunavir inhibits Cryptococcus neoformans/Cryptococcus gattii species complex growth and increases the susceptibility of biofilms to antifungal drugs

Introduction. Cryptococcus species are pathogens commonly associated with cases of meningoencephalitis in individuals who are immunosuppressed due to AIDS.Aim. The aim was to evaluate the effects of the antiretroviral darunavir alone or associated with fluconazole, 5-flucytosine and amphotericin B against planktonic cells and biofilms of Cryptococcus species.Methodology. Susceptibility testing of darunavir and the common antifungals against 12 members of the Cryptococcus neoformans/Cryptococcus gattii species complex was evaluated by broth microdilution. The interaction between darunavir and antifungals against planktonic cells was tested by a checkerboard assay. The effects of darunavir against biofilm metabolic activity and biomass were evaluated by the XTT reduction assay and crystal violet staining, respectively.Results. Darunavir combined with amphotericin B showed a synergistic interaction against planktonic cells. No antagonistic interaction was observed between darunavir and the antifungals used. All Cryptococcus species strains were strong biofilm producers. Darunavir alone reduced biofilm metabolic activity and biomass when added during and after biofilm formation (P<0.05). The combination of darunavir with antifungals caused a significant reduction in biofilm metabolic activity and biomass when compared to darunavir alone (P<0.05).Conclusion. Darunavir presents antifungal activity against planktonic cells of Cryptococcus species and synergism with amphotericin B. In addition, darunavir led to reduced biofilm formation and showed activity against mature biofilms of Cryptococcus species. Activity of the antifungals against mature biofilms was enhanced in the presence of darunavir.

Transmission of cryptococcosis by liver transplantation: A case report and review of literature

BACKGROUND

Cryptococcosis is a fungal infection caused by the yeast-like encapsulated basidiomycetous fungus of the Cryptococcus neoformans (C. neoformans) species complex. These fungi are ubiquitous in soil and bird droppings, and infection by them is an important global health concern, particularly in immunosuppressed patients, such as organ transplant recipients and those infected by the human immunodeficiency virus. The fungus usually enters the body through the respiratory tract, but extremely rare cases of infection acquired by transplantation of solid organs have been reported.

CASE SUMMARY

We report a case of disseminated cryptococcosis in a liver transplant recipient, diagnosed 2 wk after the procedure. The patient initially presented with fever, hyponatremia and elevated transaminase levels, manifesting intense headache after a few days. Blood cultures were positive for C. neoformans. Liver biopsy showed numerous fungal elements surrounded by gelatinous matrix and sparse granulomatous formations. Magnetic resonance imaging of the brain showed multiple small lesions with low signal in T2, peripheric enhancement and edematous halo, diffuse through the parenchyma but more concentrated in the subcortical regions. Treatment with amphotericin B for 3 wk, followed by maintenance therapy with fluconazole, led to complete resolution of the symptoms. The recipients of both kidneys from the same donor also developed disseminated cryptococcosis, confirming the transplant as the source of infection. The organ donor lived in a rural area, surrounded by tropical rainforest, and had negative blood cultures prior to organ procurement.

CONCLUSION

This case highlights the risk of transmission of fungal diseases, specifically of C. neoformans, through liver graft during liver transplantation.

Thiazole derivatives act on virulence factors of Cryptococcus spp

Cryptococcosis is an opportunistic or primary fungal infection considered to be the most prevalent fatal fungal disease worldwide. Owing to the limited number of available drugs, it is necessary to search for novel antifungal compounds. In the present work, we assessed the antifungal efficacy of three thiazole derivatives (1, 2, and 3). We conducted in vitro and in vivo assays to investigate their effects on important virulence factors, such as capsule and biofilm formation. In addition, the phagocytosis index of murine macrophages exposed to compounds 1, 2, and 3 and the in vivo efficacy of 1, 2, and 3 in Galleria mellonella infected with Cryptococcus spp. were evaluated. All compounds exhibited antifungal activity against biofilms and demonstrated a reduction in biofilm metabolic activity by 43-50% for C. gattii and 26-42% for C. neoformans. Thiazole compounds promoted significant changes in the capsule thickness of C. gattii compared to that of C. neoformans. Further examination of these compounds suggests that they can improve the phagocytosis process of peritoneal murine macrophages in vitro, causing an increase in the phagocytosis rate. Survival percentage was examined in the invertebrate model Galleria mellonella larvae, and only compound 3 could increase the survival at doses of 5 mg/kg after infection with C. gattii (P = .0001) and C. neoformans (P = .0007), similar to fluconazole at 10 mg/kg. The results demonstrated that thiazole compounds, mainly compound 3, have potential to be used for future studies in the search for new therapeutics for cryptococcosis.

Invasive fungal infection by Cryptococcus neoformans var. grubii with bone marrow and meningeal involvement in a HIV-infected patient: a case report

Background

Cryptococcosis is a common opportunistic infection in patients infected by Human Immunodeficiency Virus (HIV) and is the second leading cause of mortality in Acquired Immunodeficiency Syndrome (AIDS) patients worldwide. The most frequent presentation of cryptococcal infection is subacute meningitis, especially in patients with a CD4+ T Lymphocytes count below 100 cells/μL. However, in severely immunosuppressed individuals Cryptococcus neoformans can infect virtually any human organ, including the bone marrow, which is a rare presentation of cryptococcosis.

Case presentation

A 45-year-old HIV-infected male patient with a CD4+ T lymphocyte count of 26 cells/μL who presented to the emergency department with fever and pancytopenia. Throughout the diagnostic evaluation, the bone marrow aspirate culture yielded encapsulated yeasts in budding, identified as Cryptococcus sp. The bone marrow biopsy revealed a hypocellularity for age and absence of fibrosis. It was observed presence of loosely formed granuloma composed of multinucleated giant cells encompassing rounded yeast like organisms stained with mucicarmine, compatible with Cryptococcus sp. Then, the patient underwent a lumbar puncture to investigate meningitis, although he had no neurological symptoms and neurological examination was normal. The cerebrospinal fluid culture yielded Cryptococcus sp. The species and genotype identification step showed the infection was caused by Cryptococcus neoformans var. grubii (genotype VNI). The patient was initially treated with amphotericin B deoxycholate plus fluconazole for disseminated cryptococcosis, according to guideline recommendations. However, the patient developed acute kidney injury and the treatment was switched for fluconazole monotherapy. The symptoms disappeared completely with recovery of white blood cells and platelets counts. Cerebrospinal fluid cultures for fungi at one and two-weeks of treatment were negative.

Conclusions

Bone marrow infection caused by Cryptococcus neoformans is a rare presentation of cryptococcosis. The cryptococcal infection should be included for differential diagnosis in HIV-infected patients with fever and cytopenias, especially when CD4+ T lymphocytes count is below 100 cells/μL.

Diagnostic importance of eosinophilic meningitis in HIV-positive and HIV-negative patients

The presence of eosinophils in the cerebrospinal fluid (CSF) should always be considered abnormal. This study aimed to evaluate the causes of eosinophils in the CSF of patients who are HIV positive and HIV negative. This is the first study of eosinophils in the CSF of patients who are HIV-positive. This was a retrospective study of CSF reports from 1996 to 2005, patients were selected based on the presence of eosinophils in the CSF. We analyzed 20,008 CSF reports; eosinophils were present in 5%. The median and interquartile range (IQR) of eosinophils was 2% (1%, 4%). Eosinophilic meningitis (CSF eosinophils ≥ 10%) was present in 12% of the samples. The main etiologies were infectious diseases as follows: neurocysticercosis, Cryptococcus sp. meningitis, and acute bacterial meningitis. In HIV-positive cases, all causes were by infectious disease, the main pathogen being Cryptococcus sp. The probability of neurocysticercosis in a patient from an endemic region who is HIV-negative and has CSF eosinophils more than 10% was five times higher compared to a person without eosinophilic meningitis. There was a weak positive correlation between CSF eosinophils and increased serum eosinophils. Among the HIV-negative cases, the most frequent non-infectious causes were cerebrovascular syndromes, of these hemorrhage (91.5%). In the HIV-positive group, there were no cases of non-infectious cerebral disease. CSF eosinophils are suggestive of disease. The causes must be investigated, considering the most prevalent infectious diseases in the region.

Outcomes of cryptococcosis in renal transplant recipients in a less-resourced health care system

BACKGROUND

Cryptococcosis is the second most common cause of invasive fungal infections in renal transplant recipients in many countries, and data on graft outcome after treatment for this infection is lacking in less-resourced health care settings.

METHODS

Data from 47 renal transplant recipients were retrospectively collected at a single institution during a period of 13 years. Graft dysfunction, graft loss, and mortality rates were evaluated. Predictors of mortality and graft loss were estimated.

RESULTS

A total of 38 (97.4%) patients treated with amphotericin B deoxycholate (AMBd) showed graft dysfunction after antifungal initiation and 8 (18.2%) had kidney graft loss. Graft loss within 30 days after cryptococcosis onset was significantly associated with disseminated infection, greater baseline creatinine levels, and graft dysfunction concomitant to AMBd therapy and an additional nephrotoxic condition. The 30-day mortality rate was 19.2% and it was significantly associated with disseminated and pulmonary infections, somnolence at admission, high CSF opening pressure, positive CSF India ink, creatinine levels greater than 2.0 mg/dL at admission, graft dysfunction in patients treated with AMBd and an additional nephrotoxic condition and graft loss within 30 days.

CONCLUSION

Graft dysfunction was common in renal transplant recipients with cryptococcosis treated with AMBd. The rate of graft loss rate was high, most frequently in patients with concomitant nephrotoxic conditions. Therefore, the clinical focus should be on the use of less nephrotoxic lipid formulations of amphotericin B in this specific population requiring a polyene induction regimen for treatment of severe cryptococcosis in all health care systems caring for transplantation recipients.

A phenylthiazole derivative demonstrates efficacy on treatment of the cryptococcosis & candidiasis in animal models

Aim:

In this work we test 2-(2-(cyclohexylmethylene)hydrazinyl)-4-phenylthiazole (CHT) against Cryptococcus spp. and Candida albicans.

Methods:

The ability of CHT to act in biofilm and also to interfere with C. albicans adhesion was evaluated, as well as the efficiency of the CHT in cryptococcosis and candidiasis invertebrate and murine models.

Results & conclusion:

In the present work we verified that CHT is found to inhibit Cryptococcus and C. albicans affecting biofilm in both and inhibited adhesion of Candida to human buccal cells. When we evaluated in vivo, CHT prolonged survival of Galleria mellonella after infections with Cryptococcusgattii, Cryptococcusneoformans or C. albicans and promoted a reduction in the fungal burden to the organs in the murine models. These results demonstrate CHT therapeutic potential.

Candida spp. and Cryptococcus spp. cause thousands of deaths each year. In general, antifungal drugs have several limitations to their use, and there are a limited number of these drugs available to be used in the treatments of fungal diseases. This work contributes to the search for new antifungal drugs for the treatment of candidiasis and cryptococcosis, aiming in the future, after all necessary tests, to serve as a basis for the production of drugs that could be used in the treatment of patients with these fungal diseases.

The status of cryptococcosis in Latin America

Cryptococcosis is a life-threatening fungal infection caused by the encapsulated yeasts Cryptococcus neoformans and C. gattii, acquired from the environment. In Latin America, as occurring worldwide, C. neoformans causes more than 90% of the cases of cryptococcosis, affecting predominantly patients with HIV, while C. gattii generally affects otherwise healthy individuals. In this region, cryptococcal meningitis is the most common presentation, with amphotericin B and fluconazole being the antifungal drugs of choice. Avian droppings are the predominant environmental reservoir of C. neoformans, while C. gattii is associated with several arboreal species. Importantly, C. gattii has a high prevalence in Latin America and has been proposed to be the likely origin of some C. gattii populations in North America. Thus, in the recent years, significant progress has been made with the study of the basic biology and laboratory identification of cryptococcal strains, in understanding their ecology, population genetics, host-pathogen interactions, and the clinical epidemiology of this important mycosis in Latin America.

Influence of Experimental Cryptococcal Meningitis in Wistar Rats on Voriconazole Brain Penetration Assessed by Microdialysis

To make advances in the treatment of cryptococcal meningitis, it is crucial to know a given drug's free fraction that reaches the biophase. In the present study, we applied microdialysis (μD) as a tool to determine the free levels reached by voriconazole (VRC) in the brains of healthy and Cryptococcus neoformans-infected rats. The infection was induced by the intravenous (i.v.) administration of 1 × 105 CFU of yeast. The dose administered was 5 mg/kg (of body weight) of VRC, given i.v. Plasma and microdialysate samples were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and LC-UV methods. The free brain/free plasma ratio (fT) and population pharmacokinetic (popPK) analyses were performed to evaluate the impact of infection on PK parameters of the drug. The brain penetration ratio showed an increase on brain exposure in infected animals (fThealthy = 0.85 versus fTinfected = 1.86). The structural PK model with two compartments and Michaelis-Menten (MM) elimination describes the VRC concentration-time profile in plasma and tissue simultaneously. The covariate infection was included in volume of distribution in the peripheral compartment in healthy animals (V2) and maximum rate of metabolism (VM ). The levels reached in infected tissues were higher than the values described for MIC of VRC for Cryptococccus neoformans (0.03 to 0.5 μg ml-1), indicating its great potential to treat meningitis associated with C. neoformans.

The epidemiology of cryptococcosis and the characterization of Cryptococcus neoformans isolated in a Brazilian University Hospital

Cryptococcosis, a systemic disease caused by the fungus Cryptococcusneoformans/ Cryptococcusgattii is more severe in immunocompromised individuals. This study aimed to analyze the epidemiology of the disease, the molecular characteristics and the antifungal susceptibility of C. neoformans isolated from patients treated in a Brazilian university hospital. This retrospective study was conducted in the Clinical Hospital, Federal University of Uberlândia, and evaluated cases of cryptococcosis and strains of C. neoformans isolated from 2004 to 2013. We evaluated 41 patients, 85% of whom were diagnosed with AIDS. The fungus was isolated from the cerebrospinal fluid (CSF) of 21 patients (51%); 19.5% had fungemia and in 24% the agent was isolated from the CSF and blood, concurrently. Meningoencephalitis was the most frequent (75%) manifestation of infection. Despite adequate treatment, the mortality of the disease was 58.5%. Most isolates (97.5%) presented the VNI genotype (serotype A, var. grubii) and one isolate was genotyped as C. gattii (VGI); all the isolates were determined as mating type MATa and showed susceptibility to the tested antifungals (fluconazole, voriconazole, amphotericin B and 5-flucytosine). Although AIDS detection rates remain stable, opportunistic infections such as cryptococcosis remain as major causes of morbidity and mortality in these patients.

Targeting CYP51 for drug design by the contributions of molecular modeling

CYP51 is an enzyme of sterol biosynthesis pathway present in animals, plants, protozoa and fungi. This enzyme is described as an important drug target that is still of interest. Therefore, in this work, we reviewed the structure and function of CYP51 and explored the molecular modeling approaches for the development of new antifungal and antiprotozoans that target this enzyme. Crystallographic structures of CYP51 of some organisms have already been described in the literature, which enable the construction of homology models of other organisms' enzymes and molecular docking studies of new ligands. The binding mode and interactions of some new series of azoles with antifungal or antiprotozoan activities has been studied and showed important residues of the active site. Molecular modeling is an important tool to be explored for the discovery and optimization of CYP51 inhibitors with better activities, pharmacokinetics, and toxicological profiles.

The Simultaneous Occurrence of Histoplasmosis and Cryptococcal Fungemia: A Case Report and Review of the Literature

Simultaneous infections with Cryptococcus neoformans and Histoplasma capsulatum are rare and typically occur in immunocompromised individuals, particularly AIDS patients. Because both of those fungi can spur the development of latent infections, it is generally unknown which organism was first present. The diagnosis of one fungus can hide the diagnosis of the other, leading to underdiagnoses and poor prognosis. We report a case of C. neoformans and H. capsulatum co-infection. We also performed a systematic review of the literature. Our patient, a 69-year-old HIV-negative man, presented with a 9-month history of a productive cough, dyspnea and wheezing. His history showed chronic obstructive pulmonary disease and type II diabetes mellitus (DM). Pulmonary lesions of unidentified etiology were noted. Cryptococcal involvement of the central nervous system was confirmed, and C. neoformans and H. capsulatum were also isolated from blood cultures. In the literature, we found ten cases of simultaneous histoplasmosis and cryptococcosis. Including our patient, all of the cases were located in North America and Latin America, except for two, one Indian and one African diagnosed in France. AIDS was the main predisposing factor, followed by DM and age >60 years. Several diagnostic methods were employed. A blood culture and bronchoalveolar lavage (BAL) culture resulted in the growth of C. neoformans in most of the cases. H. capsulatum was more often detected in BAL and bone marrow cultures. Although co-infection by these pathogens is severe, it can be cured if it is diagnosed and treated early. We emphasized the importance of clinical suspicion and differential diagnosis of systemic mycoses.

FATAL DISSEMINATED CRYPTOCOCCOSIS WITH RENAL INVOLVEMENT IN AN HIV-INFECTED PATIENT

Introduction:

We present a fatal case of disseminated cryptococcosis in a young man whose diagnosis of HIV infection was made at the time of admission to the emergency room.

Case report:

The patient was a twenty-three-year-old man, with a history of daily fever during one month associated with diarrhea, weight loss, headache, vomiting and generalized seizures. He also had a history of diabetes mellitus, alcoholism and drug addiction. Upon physical examination the patient was pale, disoriented and had periods of agitation. White blood cells count was 3,440/mm³ (5% lymphocytes), hemoglobin was 10g/dL, platelets were 83,000/ mm³. Creatinine was 0.7 mg/dL; urea 19 mg/dL; Na, K, and liver enzymes were within normal limits. Lactic dehydrogenase was 494 IU/L. Cerebrospinal fluid (CSF) analysis revealed 10 white blood cells/mm³ (58% neutrophils, 31% lymphocytes, 11% monocytes) and 2 red blood cells/mm³. India ink test revealed six Cryptococcus yeasts/mm³. CSF glucose was 122 mg/dL and protein was 36 mg/ dL. VDRL test was negative and anti-HIV test was positive. Intravenous hydration, insulin, phenytoin, fluconazole, pyrimethamine, sulfadiazine, folinic acid, and amphotericin B were started. The patient did not improve and became obtunded and hypotensive. He was intubated and put on mechanical respiration. He received vasoactive drugs and died less than 24 hours after admission. A postmortem examination was performed and revealed disseminated cryptococcosis, with severe involvement of the kidneys.

Conclusion:

Cryptococcosis, as a rule, is a systemic disease that affects mostly immunocompromised individuals, especially patients with AIDS. When diagnosed late in its course it has a very high mortality.

Cryptococcus spp. em excretas de Columba livia (pombos domésticos) provenientes de um hospital universitário no Sul do Brasil

RESUMO A criptococose é uma micose primariamente pulmonar, sendo adquirida por meio de inalação de propágulos fúngicos infectantes encontrados no ambiente. Um dos principais agentes etiológicos da criptococose é a espécie Cryptococcus neoformans , que apresenta distribuição mundial. O objetivo desse trabalho foi pesquisar a ocorrência de Cryptococcus spp. em excretas de Columba livia (pombos domésticos) encontradas na área externa do prédio do Hospital Universitário Dr. Miguel Riet Correa Junior, centro de referência para o tratamento da Síndrome da Imunodeficiência Adquirida na região sul do estado do Rio Grande do Sul, Brasil. Durante um período de dez meses, foi coletado um total de 40 amostras de excretas secas da área acadêmica e da área hospitalar do Hospital Universitário. As excretas foram adicionadas de solução salina com cloranfenicol, homogeneizados em vórtex, semeados em ágar Níger e incubados a 25ºC com observações diárias até sete dias. A identificação do micro-organismo foi realizada por provas fenotípicas e bioquímicas. Das 40 amostras processadas e analisadas, 13 (32,5%) foram positivas para o isolamento de Cryptococcus spp., variando de 20.000 a 3.000.000 UFC/g de fezes. O isolamento desse fungo em um ambiente hospitalar é relevante em saúde pública, pois evidencia a exposição dos indivíduos que frequentam esse local a propágulos infectantes.

Thiazole compounds with activity against Cryptococcus gattii and Cryptococcus neoformans in vitro

Human cryptococcosis can occur as a primary or opportunistic infection and develop as an acute, subacute, or chronic, systemic infection involving different host organs. We evaluated the antifungal activity of thirteen compounds against Cryptococcus gattii and Cryptococcus neoformans in vitro, by assessing the toxicity of the compounds showing the greatest antifungal activity in VERO cells and murine macrophages. From these results, four compounds were considered promising for further studies because they displayed low cytotoxicity and significant antifungal activity. The heterocyclic compounds 1b, 1c, 1d, and 1m have antifungal activity levels between that of amphotericin B and fluconazole in vitro. The death curve of Cryptococcus spp. treated with these four compounds was similar to the curve obtained for amphotericin B, in that we observed a significant reduction in cell viability within the first 24 h of treatment. Additionally, we found that there was no effect when these compounds were combined with amphotericin and fluconazole, except for 1c, which antagonized the effect of amphotericin B against C. gattii, also reflected in the reduction of the post-antifungal effect (PAFE); however, this interaction did not alter the ergosterol content. The results shown in this paper reveal the discovery of novel thiazole compounds, which are easy to synthesize, and with potentially exhibit antifungal activity, and display low cytotoxicity in normal mammalian cells. These compounds can be used as prototypes for the design of new antifungal drugs against C. gattii and C. neoformans.

Pulmonary cryptococcoma: a rare and challenging diagnosis in immunocompetent patients

Cryptococcal infection is commonly seen in immunocompromised patients, although immunocompetent patients may also be infected. The pathogen's portal of entry is the respiratory tract; however, the central nervous system is predominantly involved. Pulmonary involvement varies from interstitial and alveolar infiltrations to large masses, which are frequently first interpreted as lung neoplasm. The diagnosis of pulmonary cryptococcosis, in these cases, is frequently challenging, which, in most cases, requires histopathological examination. The authors report the case of a young female patient who presented a 20-day history of chest pleuritic pain and fever at the onset of symptoms. HIV serology was negative and CD4 count was normal. The imaging work-up was characterized by a huge opacity in the left inferior pulmonary lobe with a wide pleural base. Computed tomography showed a heterogeneous mass involving the bronchial tree. Mediastinal involvement was poor, and there was a splenomegaly. The patient underwent an exploratory thoracotomy and inferior lobectomy. The histopathological examination revealed a cryptococcoma. As the serum antigenemia was positive, the patient was scheduled for long-term treatment with fluconazole. The authors call attention to including the cryptococcal infection in the differential diagnosis of lung mass, mainly when localized in the lung bases in immunocompetent patients.

Clinical significance of the isolation of Candida species from hospitalized patients

In this study, we isolated and phenotypically identified 108 yeast strains from various clinical specimens collected from 100 hospitalized patients at three tertiary hospitals in São Luís-Maranhão, Brazil, from July to December 2010. The isolates were analyzed for their susceptibility to four of the most widely used antifungal agents in the surveyed hospitals, amphotericin B, fluconazole, 5-flucytosine and voriconazole. The species identified were Candida albicans (41.4%), Candida tropicalis (30.1%), C. glabrata (7.4%), Candida parapsilosis (5.5%), Candida krusei (4.6%), Cryptococcus neoformans (4.6%), Trichosporon spp . (3.7%), Candida norvegensis (0.9%), Rhodotorula glutinis (0.9%) and Pichia farinosa (0.9%). A higher isolation rate was observed in the following clinical specimens: urine (54 isolates; 50%), respiratory tract samples (21 isolates; 19.4%) and blood (20 isolates; 18.6%). Candida albicans isolates were 100% sensitive to all antifungal agents tested, whereas Candida krusei and Crytococcus neoformans displayed intermediate resistance to 5-flucytosine, with Minimal Inhibitory Concentration (MIC) values of 8 mg/mL and 16 mg/mL, respectively. Both strains were also S-DD to fluconazole with an MIC of 16 mg/mL. C. tropicalis was resistant to 5-flucytosine with an MIC of 32 μg/mL. This study demonstrates the importance of identifying the yeast species involved in community and nosocomial infections.

Cryptococcosis, silicosis, and tuberculous pseudotumor in the same pulmonary lobe

Tuberculosis and cryptococcosis are infectious diseases that can result in the formation of single or multiple nodules in immunocompetent patients. Exposure to silica is known to raise the risk of infection with Mycobacterium tuberculosis. We report the case of an elderly man with no history of opportunistic infections and no clinical evidence of immunodeficiency but with a six-month history of dry cough and nocturnal wheezing. A chest X-ray revealed a mass measuring 5.0 × 3.5 cm in the right upper lobe. The diagnostic approach of the mass revealed tuberculosis. The histopathological analysis of the surrounding parenchyma reveled silicosis and cryptococcosis. Cryptococcosis was also found in masses identified in the mediastinal lymph nodes. The surgical approach was indicated because of the degree of pleuropulmonary involvement, the inconclusive results obtained with the invasive and noninvasive methods applied, and the possibility of malignancy. This case illustrates the difficulty inherent to the assessment of infectious or inflammatory pulmonary pseudotumors, the differential diagnosis of which occasionally requires a radical surgical approach. Despite the presence of respiratory symptoms for six months, the first chest X-ray was performed only at the end of that period. We discuss the possible pathogenic mechanisms that might have led to the combination of three types of granulomatous lesions in the same lobe, and we emphasize the need for greater awareness of atypical presentations of pulmonary tuberculosis.

First report on Cryptococcus neoformans in pigeon excreta from public and residential locations in the metropolitan area of Cuiabá, State of Mato Grosso, Brazil

Cryptococcosis is a severe systemic mycosis caused by two species of Cryptococcus that affect humans and animals: C. neoformans and C. gattii. Cosmopolitan and emergent, the mycosis results from the interaction between a susceptible host and the environment. The occurrence of C. neoformans was evaluated in 122 samples of dried pigeon excreta collected in 49 locations in the City of Cuiabá, State of Mato Grosso, Brazil, including public squares (n = 5), churches (n = 4), educational institutions (n = 3), health units (n = 8), open areas covered with asbestos (n = 4), residences (n = 23), factory (n = 1) and a prison (n = 1). Samples collected from July to December of 2010 were seeded on Niger seed agar (NSA). Dark brown colonies were identified by urease test, carbon source assimilation tests and canavanine-glycine-bromothymol blue medium. Polymerase chain reaction primer pairs specific for C. neoformans were also used for identification. Cryptococcus neoformans associated to pigeon excreta was isolated from eight (6.6%) samples corresponding to six (12.2%) locations. Cryptococcus neoformans was isolated from urban areas, predominantly in residences, constituting a risk of acquiring the disease by immunocompromised and immunocompetent individuals.

[Occurrence of Cryptococcus neoformans in pigeon excrement in the city of Pelotas, State of Rio Grande do Sul]

INTRODUCTION

Cryptococcus neoformans is an encapsulated yeast and is the etiological agent for human and animal cryptococcosis. It is found in sources within the environment, including pigeon excrement, and is an important cause of mortality among immunocompromised individuals worldwide.

METHODS

Seventy different environments in the city of Pelotas, Rio Grande do Sul, were surveyed for the purpose of investigating Cryptococcus neoformans occurrences in pigeon excreta. The environments included buildings, public squares and outdoor locations in the city. After collection, chloramphenicol saline solution was added to the excreta, which were then homogenized and seeded onto Sabouraud agar with chloramphenicol and onto Niger agar, and incubated at 32 degrees C. Identification was performed by direct examination and by means of the phenoloxidase and urease tests, carbohydrate assimilation and culturing in CGB medium.

RESULTS

Out of the sites investigated (n = 70), 26 (37.1%) of them contained pigeon excreta. These included historical buildings (n = 8), a church tower (n = 1), rice mills and warehouses (n = 7), a public square (n = 1) and outdoor locations (n = 9). Cryptococcus neoformans was isolated from 26.9% (n = 7/26) of these locations.

CONCLUSIONS

This study draws attention to isolation of this fungus in urban areas that present large accumulations of pigeon excrement. This represents a risk to public health, especially for immunocompromised individuals.

Unusual morphologies of Cryptococcus spp. in tissue specimens: report of 10 cases

Ten cases of cryptococcosis due to unusual microscopic forms of Cryptococcus sp. observed over a twenty-eight year period (1981-2009) are presented. The most important clinicopathological and laboratory data are tabulated. The uncommon forms of cryptococcal cells given are: structures resembling germ tube (one case), chains of budding yeasts (one case), pseudohyphae (two cases) and nonencapsulated yeast-like organisms (eight cases). The diagnosis was based on the histopathological findings. The causative organism was isolated and identified in seven cases; five were due to C. neoformans, and two to C. gattii. In addition, the importance of using staining histochemical techniques - Grocott's silver stain (GMS), Mayer's mucicarmine stain (MM) and Fontana-Masson stain (FM) - in the diagnosis of cryptococcosis is argued.