Pneumonia and pleural effusion due to Cryptococcus laurentii in a clinically proven case of AIDS

Cryptococcus neoformans Genotypic Diversity and Disease Outcome among HIV Patients in Africa

Cryptococcal meningoencephalitis, a disease with poor patient outcomes, remains the most prevalent invasive fungal infection worldwide, accounting for approximately 180,000 deaths each year. In several areas of sub-Saharan Africa with the highest HIV prevalence, cryptococcal meningitis is the leading cause of community-acquired meningitis, with a high mortality among HIV-infected individuals. Recent studies show that patient disease outcomes are impacted by the genetics of the infecting isolate. Yet, there is still limited knowledge of how these genotypic variations contribute to clinical disease outcome. Further, it is unclear how the genetic heterogeneity of C. neoformans and the extensive phenotypic variation observed between and within isolates affects infection and disease. In this review, we discuss current knowledge of how various genotypes impact disease progression and patient outcome in HIV-positive populations in sub-Saharan African, a setting with a high burden of cryptococcosis.

Comparison of clinical and biological characteristics of HIV-infected patients presenting Cryptococcus neoformans versus C. curvatus/C. laurentii meningitis

Background

Cryptococcal meningitis is mainly caused by Cryptococcus neoformans/C. gattii complex. We compared the clinical, biological, and antifungal susceptibility profiles of isolates from HIV-Infected Patients (HIVIP) with C. neoformans (Cn) versus C. curvatus/C. laurentii (Cc/Cl) meningitis.

Methods

Comparative analytical study were conducted. Apart from patients’ clinical data, the following analysis were performed and the results were compared in both groups: biochemical examination, cryptococcal antigen test, India ink staining, and culture on Cerebral Spinal Fluid (CSF), strains identification by mass spectrometry, ITS sequencing, PCR serotyping and antifungal susceptibility. The main outcome variable was the “species of Cryptococcus identified”, which was compared to other variables of the same type using the Pearson Chi-square test or the Fisher exact test.

Results

A total of 23 (79.3%) Cn meningitis cases versus 6 (20.7%) Cc/Cl meningitis were retained.Cn meningitis was more frequently associated with headache (100% vs 50%, p = 0.005) than Cc/Cl meningitis and meningeal signs were more frequent in Cn infected patients. Biologically, hypoglycorrhachia and low CD₄ count were more observed in Cn group (90% vs 20% of patients, p = 0.01; 45.6 vs 129.8 cells/µL, p = 0.02, respectively). A higher proportion of Cn strains (91.3%) showed a low Minimum Inhibitory Concentration (MIC) (< 8 mg/L) for fluconazole compared to Cc/Cl strains (66.7%). Also, Cc/Cl strains resistant to 5-flucytosine and amphotericin B were found in 16.7% of cases for each of the two antifungal agents. Cryptococcus detection by routine analysis (India ink, culture, and antigens) was better for Cn samples than Cc/Cl. Except ITS sequencing, which identified all strains of both groups, mass spectrometry and serotyping PCR identified Cn strains better than Cc/Cl (100% vs 80%, p = 0.1; 100% vs 0%, p < 0.0001, respectively). After treatment with amphotericin B, 5-flucytosine, and fluconazole in both groups, the outcome was similar.

Conclusions

Clinical presentation of Cn meningitis is certainly more severe than that of Cc/Cl meningitis, but Cc/Cl infection should be considered in the management of HIVIP with meningeal syndrome because of the diagnostic difficulty and the high MICs of antifungal agents required for the treatment of meningitis due to these cryptococcal species.

Titan cell formation is unique to Cryptococcus species complex

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

Comparison of Cryptococcus gattii/neoformans Species Complex to Related Genera (Papiliotrema and Naganishia) Reveal Variances in Virulence Associated Factors and Antifungal Susceptibility

Cryptococcosis is an infectious disease of worldwide distribution, caused by encapsulated yeasts belonging to the phylum Basidiomycota. The genus Cryptococcus includes several species distributed around the world. The C. gattii/neoformans species complex is largely responsible for most cases of cryptococcosis. However, clinical series have been published of infections caused by Papiliotrema (Cryptococcus) laurentii and Naganishia albida (Cryptococcus albidus), among other related genera. Here, we examined the pathogenic potential and antifungal susceptibility of C. gattii/neoformans species complex (clades I and II) and related genera (Papiliotrema and Naganishia) isolated from environmental and clinical samples. P. laurentii (clade III), N. liquefasciens/N. albidosimilis (clade IV); and N. adeliensis/N. albida (clade V) strains produced higher levels of phospholipase and hemolysins, whereas the C. gattii/neoformans species complex strains (clades I and II) had markedly thicker capsules, produced more biofilm biomass and melanin, which are known virulence attributes. Interestingly, 40% of C. neoformans strains (clade II) had MICs above the ECV established for this species to amphotericin B. Several non-C. gattii/neoformans species complex (clades III to V) had MICs equal to or above the ECVs established for C. deuterogattii and C. neoformans for all the three antifungal drugs tested. Finally, all the non-C. gattii/neoformans clinical isolates (clades III to V) produced more melanin than the environmental isolates might reflect their particularly enhanced need for melanin during in vivo protection. It is very clear that C. gattii/neoformans species complex (clades I and II) strains, in general, show more similar virulence phenotypes between each other when compared to non-C. gattii/neoformans species complex (clades III to V) isolates. These observations together with the fact that P. laurentii and Naganishia spp. (clades III to V) strains were collected from the outside of a University Hospital, identify features of these yeasts important for environmental and patient colonization and furthermore, define mechanisms for infections with these uncommon pathogens.

Occurrence and Distribution of Cryptococcus Species in Environmental Sources from Lower Assam Belt of India

Cryptococcus is a non-motile, gram positive, non-fermenting Basidiomycetous encapsulated yeast like fungus that causes respiratory, neurological and other systemic diseases in both humans and animals. Present study delineates the possible distribution of Cryptococcus species in pigeon droppings, excreta of other avian species, eucalyptus tree and contaminated soil specimens collected from different geographical co-ordinates of six geographical regions of the lower Brahmaputra Valley of Assam, India. The fungi were isolated through conventional methods of Sabouraud Dextrose Agar (SDA) and Bird Seed Agar (BSA) media and identified through negative staining of capsule as well as performing classical bio-chemical tests. Identity of the isolates was further confirmed through sequence analysis of ITS-1 and ITS-4 region of the 18S rDNA. Two pathogenic species of Cryptococcus were isolated from 67 (15.40%) of the 435 specimens. Of these positive isolates 41 (9.43%) belonged to Naganishia albida (Cryptococcus albidus) while 26 (5.98%) represented Papiliotrema laurentii (Cryptococcus laurentii). Both the species were recovered from 58 (18.35%) dry and 9 (7.56%) moist specimens. The percentage of prevalence of Naganishia albida in dry and moist specimens were 35 (11.07%) and 6 (5.04%) respectively. Contrary to this, the percentage of prevalence of Papiliotrema laurentii in dry and moist were 23 (7.28%) and 3 (2.52%) respectively. The findings indicate that Cryptococcus species have established a better ecological sustenance in dry specimens than moist. The findings of the investigation demonstrated that the prevalence of Cryptococcus albidus in attics, dovecotes / houses of pigeon fanciers, contaminated soil, eucalyptus tree and droppings of other birds were 11(12.36%) out of 89, 23(14.11%) of 163,2(3.23%) of 62,4(7.84%) of 51 and only 1(1.43%) out of 7 specimens respectively. The recovery of Papiliotrema laurentii in the above specimens were 3(3.37%), 20(12.27%), 1(1.61%), 1(1.96%) and 1(1.42%) respectively. The findings revealed that the prevalence of Naganishia albida is more than that of Papiliotrema laurentii in natural substrates. The notorious pathogenic fungi, Cryptococcus neoformans could not be isolated, indicative of the fact that the region selected for the study is not environmentally favorable for growth and sustenance of the species. Findings of the study clearly demonstrate the ecological and epidemiological significance of the non-neoformans species of the genus cryptococcus that needs further comprehensive studies to access the prevalence of the genus from public health point of view.

A rare case of cutaneous Papiliotrema (Cryptococcus) laurentii infection in a 23-year-old Caucasian woman affected by an autoimmune thyroid disorder with hypothyroidism

In recent years, the frequency of infections due to saprophytic fungi has increased. Cryptococcus laurentii, recently classified as Papiliotrema laurentii, is responsible for fungemia, meningitis, and superficial infections. Here, we report the first case of cutaneous Papiliotrema (Cryptococcus) laurentii infection in a 23-year-old Caucasian woman affected by an autoimmune thyroiditis with hypothyroidism. Impairments of the immune system are often associated with unusual fungal infections, which cannot be neglected. The isolate strain was susceptible to Amphotericin B while resistant to fluconazole, itraconazole, voriconazole, and terbinafine. The patient was successfully treated with Amphotericin B.

Fatal fungaemia due to Cryptococcus albidus in an elderly diabetic woman presenting with pleural effusion

This is a fatal case of fungaemia due to Cryptococcus albidus in an elderly woman with type 2 diabetes mellitus who presented pleural effusion as the only clinical presentation. Not only infections of the pleura are uncommon presentations of pulmonary cryptococcosis, but these infections due to non-C. neoformans species are extremely rare. This report places C. albidus on the growing number of disseminated mycosis-causing agents in diabetic patients.

First case of minimal change nephrotic syndrome resolving with antifungal therapy for isolated pleural cryptococcal infection

We report the case of a 71-year-old male with poorly controlled diabetes mellitus who presented with lower extremity edema and acute renal failure. He was diagnosed with nephrotic syndrome secondary to minimal change disease (MCD). Treatment with steroids was withheld due to concern for hyperglycemia in the context of his poorly controlled diabetes mellitus. A week after discharge, he was subsequently re-hospitalized four times within a month with pleural effusions, dyspnea, and fever. Work up revealed isolated pleural cryptococcosis, demonstrated on two separate admissions. There was neither evidence of disseminated disease nor immunocompromising condition. Immunosuppression was not initiated for the treatment of MCD in the setting of poorly controlled diabetes and active infection. After six months of treatment with fluconazole 400 mg/day, the nephrotic syndrome, renal failure, and cryptococcal pleuritis resolved. This case is the first to our knowledge of isolated pleural cryptococcosis associated with nephrotic syndrome. The patient’s course lends further support to the hypothesis that there may be causal relationship between cryptococcosis and nephrotic syndrome.

Clinical diversity of invasive cryptococcosis in AIDS patients from central China: report of two cases with review of literature

Background

Although antiretroviral therapy (ART) has greatly improved the prognosis of acquired immunodeficiency syndrome (AIDS) patients globally, opportunistic infections (OIs) are still common in Chinese AIDS patients, especially cryptococcosis.

Case presentation

We described here two Chinese AIDS patients with cryptococcal infections. Case one was a fifty-year-old male. At admission, he was conscious and oriented, with papulonodular and umbilicated skin lesions, some with ulceration and central necrosis resembling molluscum contagiosum. The overall impression reminded us of talaromycosis: we therefore initiated empirical treatment with amphotericin B, even though the case history of this patient did not support such a diagnosis. On the second day of infusion, the patient complained of intermittent headache, but the brain CT revealed no abnormalities. On the third day, a lumbar puncture was performed. The cerebral spinal fluid (CSF) was turbid, with slightly increased pressure. India ink staining was positive, but the cryptococcus antigen latex agglutination test (CrAgLAT: IMMY, USA) was negative. Two days later, the blood culture showed a growth of Cryptococcus neoformans, and the same result came from the skin culture. We added fluconazole to the patient’s treatment, but unfortunately, he died three days later.

Case two was a sixty-four-year-old female patient with mild fever, productive cough, dyspnea upon movement, and swelling in both lower limbs. The patient was empirically put on cotrimoxazole per os and moxifloxacin by infusion. A bronchofibroscopy was conducted with a fungal culture, showing growth of Cryptococcus laurentii colonies. Amphotericin B was started thereafter but discontinued three days later in favor of fluconazole 400 mg/d due to worsening renal function. The patient became afebrile after 72 h of treatment with considerable improvement of other comorbidities and was finally discharged with continuing oral antifungal therapy.

Conclusions

Our cases illustrate that cryptococcal disease is an important consideration when treating immunocompromised individuals such as AIDS patients. Life threatening meningitis or meningoencephalitis caused by C. neoformansmay still common in these populations and can vary greatly in clinical presentations, especially with regard to skin lesions. Pulmonary cryptococcosis caused by C. laurentii is rare, but should also be considered in certain contexts. Guidelines for its earlier diagnosis, treatment and prophylaxis are needed.

Cryptococcal pleuritis with pleural effusion as the only clinical presentation in a patient with hepatic cirrhosis: A case report and literature review

RATIONALE

Cryptococcosis is a significant life-threatening fungal infection in worldwide, mainly reported in immunocompromised patients. Pleural effusion presentation of cryptococcal infection as the only clinical presentation is rarely seen in pulmonary cryptococcosis, which may lead to be misdiagnosed, and the study on this subject will provide further insights.

PATIENT CONCERNS

A 64-year-old man was hospitalized in our department and diagnosed as hepatic B cirrhosis. A computed tomography (CT) of the thorax showed a massive right pleural effusion without pulmonary parenchymal abnormalities. He was started on empirical treatment for pleural tuberculosis (TB). However, during his hospitalization, a right pleural effusion developed and fever was not controlled.

DIAGNOSES

On day 14 admission, pleural fluid cultured positive for Cryptococcus neoformans. The C neoformans isolate belonged to ST5 and molecular type VNI (var. grubii).

INTERVENTIONS

The patient was diagnosed with cryptococcal pleuritis, then amphotericin B and fluconazole were administrated.

OUTCOMES

Finally, the patient was improved and discharged from our hospital.

LESSONS

Similar cases in cryptococcal pleuritis patients with pleural effusion as the only clinical presentation in the literature are also reviewed. Through literature review, we recommend that pleural effusion cryptococcal antigen test should be used to diagnose cryptococcal pleuritis to reduce misdiagnosis. The early administration of antifungal drug with activity to Cryptococcus seemed beneficial in preventing dissemination of cryptococcosis.

Scalp microbiota alterations in children with pediculosis

Pediculosis is a disease caused by the insect Pediculus humanus capitis that mainly occurs in childhood. A comparative study was carried out evaluating groups of schoolchildren with (group A) and without pediculosis (group B) to analyse the characteristics of the scalp microbiota. Samples were collected by swab using Stuart transport medium and incubate in Sabouraud dextrose agar with tetracycline to analyse the fungal microbiota and in blood agar to assess the bacterial microbiota. The isolates identity was confirmed by sequencing of the 16S and 18S regions of the ribosomal DNA gene for bacteria and fungi, respectively. The analysis of the 186 isolates led to the identification of 35 bacteria and 40 fungi in group A and 47 bacteria and 64 fungi in group B. The results indicate differences in bacterial and fungal species in the groups analysed. In the observed bacterial microbiota, Staphylococcus capitis occurred more frequently than Staphylococcus epidermidis in group A vs B. Among fungal isolates, Debaryomyces sp. was more frequent in group B vs A. Our findings showed scalp microbiota alterations in children with pediculosis, meriting future studies to analyse the relationship between these agents and their impact on human health.

Cryptococcus neoformans empyema in a patient receiving ibrutinib for diffuse large B-cell lymphoma and a review of the literature

We report a case of Cryptococcus neoformans pulmonary infection complicated by empyema in a 79-year-old man with diffuse large B-cell lymphoma treated with R-CHOP and ibrutinib. A literature review identified 25 cases of cryptococcal pleural disease published since 1980. Most cases were caused by the C. neoformans species in immunocompromised hosts with an exudative pleural effusion and lymphocyte-predominant infiltrate. The cryptococcal antigen test was often positive when pleural fluid and serum were tested. The outcome was favourable in most cases with antifungal therapy and either thoracocentesis or surgical resection. We also identified 40 cases of opportunistic infections, most commonly aspergillosis, cryptococcosis and Pneumocystis jirovecii pneumonia, in patients treated with ibrutinib. In vitro studies indicate Bruton tyrosine kinase inhibition impairs phagocyte function and offer a mechanism for the apparent association between ibrutinib and invasive fungal infections.

Cryptococcus laurentii fungemia in a low birth weight preterm neonate: India

In the last few years, Cryptococcus laurentii infections have increased, particularly in immunocompromised patients. Here we report the first case of C. laurentii fungemia in low birth weight preterm infant from India. A preterm neonate was admitted for feeding intolerance and respiratory distress. Blood culture ascertained the causative organism as C. laurentii. The isolated strain was found susceptible to amphotericin B and the patient recovered following the administration of amphotericin B (5mg/kg body weight) for 8days.

Perspectives on non-neoformans cryptococcal opportunistic infections

Non-neoformans Cryptococcus species, including C. laurentii and C. albidus, have historically been classified as exclusively saprophytic. However, recent studies have increasingly implicated these organisms as the causative agent of opportunistic infections in humans. Herein, the case is presented of C. laurentii meningitis in a critically ill patient receiving corticosteroids. C. laurentii has been implicated in an additional 18 cases of opportunistic infection, predominantly of the skin, bloodstream, and central nervous system. The most clinically significant risk factors for non-neoformans cryptococcal infections include: impaired cell-mediated immunity, recent corticosteroid use, and invasive catheter placement. This article provides a comprehensive review of the clinical relevance, pathogenesis, risk factors, and treatment of non-neoformans Cryptococcus species.

Cryptococcosis today: It is not all about HIV infection

Purpose of the review

Cryptococcal disease is most often thought of in the context of HIV infection. Much of our knowledge of the disease originates from its management in the HIV-positive population over the last 30 years. While the majority of cases globally continue to occur in the setting of advanced HIV, Cryptococcus species is increasingly responsible for disease in HIV-negative populations including those considered normal hosts and these HIV-negative populations will be the focus of this review.

Recent findings

Currently available data indicated that significant differences exist in epidemiology, clinical presentation, management and outcomes of cryptococcal disease in HIV-negative populations when compared to those living with HIV.

Summary

Further research is required to improve our knowledge of cryptococcal disease in particular in HIV-negative cohorts so as to optimise management of the disease in the future.

A Case of Disseminated Infection with Skin Manifestation due to Non-neoformans and Non-gattii Cryptococcus in a Patient with Refractory Acute Myeloid Leukemia

Cryptococcus spp. other than Cryptococcus neoformans or Cryptococcus gattii were previously considered saprophytes and thought to be non-pathogenic to humans. However, opportunistic infections associated with non-neoformans and non-gattii species, such as Cryptococcus laurentii and Cryptococcus albidus, have increased over the past four decades. We experienced a case of cryptococcosis caused by non-neoformans and non-gattii spp. in a 47-year-old female with refractory acute myeloid leukemia after allogeneic hematopoietic stem cell transplantation. The patient underwent salvage chemotherapy with fluconazole prophylaxis and subsequently developed neutropenic fever with multiple erythematous umbilicated papules. A skin biopsy revealed fungal hyphae and repetitive blood cultures showed yeast microorganisms that were identified later as C. laurentii by Vitek-II^®. Skin lesions and fever began to improve with conventional amphotericin B therapy. The treatment regimen was continued for 21 days until the disseminated cryptococcosis was completely controlled.

Comparative Evaluation of the BD Phoenix Yeast ID Panel and Remel RapID Yeast Plus System for Yeast Identification

Becton Dickinson Phoenix Yeast ID Panel was compared to the Remel RapID Yeast Plus System using 150 recent clinical yeast isolates and the API 20C AUX system to resolve discrepant results. The concordance rate between the Yeast ID Panel and the RapID Yeast Plus System (without arbitration) was 93.3% with 97.3% (146/150) and 95.3% (143/150) of the isolates correctly identified by the Becton Dickinson Phoenix and the Remel RapID, respectively, with arbitration.

Phylogenetic analysis of phenotypically characterized Cryptococcus laurentii isolates reveals high frequency of cryptic species

BACKGROUND

Although Cryptococcus laurentii has been considered saprophytic and its taxonomy is still being described, several cases of human infections have already reported. This study aimed to evaluate molecular aspects of C. laurentii isolates from Brazil, Botswana, Canada, and the United States.

METHODS

In this study, 100 phenotypically identified C. laurentii isolates were evaluated by sequencing the 18S nuclear ribosomal small subunit rRNA gene (18S-SSU), D1/D2 region of 28S nuclear ribosomal large subunit rRNA gene (28S-LSU), and the internal transcribed spacer (ITS) of the ribosomal region.

RESULTS

BLAST searches using 550-bp, 650-bp, and 550-bp sequenced amplicons obtained from the 18S-SSU, 28S-LSU, and the ITS region led to the identification of 75 C. laurentii strains that shared 99-100% identity with C. laurentii CBS 139. A total of nine isolates shared 99% identity with both Bullera sp. VY-68 and C. laurentii RY1. One isolate shared 99% identity with Cryptococcus rajasthanensis CBS 10406, and eight isolates shared 100% identity with Cryptococcus sp. APSS 862 according to the 28S-LSU and ITS regions and designated as Cryptococcus aspenensis sp. nov. (CBS 13867). While 16 isolates shared 99% identity with Cryptococcus flavescens CBS 942 according to the 18S-SSU sequence, only six were confirmed using the 28S-LSU and ITS region sequences. The remaining 10 shared 99% identity with Cryptococcus terrestris CBS 10810, which was recently described in Brazil. Through concatenated sequence analyses, seven sequence types in C. laurentii, three in C. flavescens, one in C. terrestris, and one in the C. aspenensis sp. nov. were identified.

CONCLUSIONS

Sequencing permitted the characterization of 75% of the environmental C. laurentii isolates from different geographical areas and the identification of seven haplotypes of this species. Among sequenced regions, the increased variability of the ITS region in comparison to the 18S-SSU and 28S-LSU regions reinforces its applicability as a DNA barcode.

HIV-Mycobacterium tuberculosis co-infection: a 'danger-couple model' of disease pathogenesis

Tuberculosis (TB) and human immunodeficiency virus (HIV) infection interfere and impact the pathogenesis phenomena of each other. Owing to atypical clinical presentations and diagnostic complications, HIV/TB co-infection continues to be a menace for healthcare providers. Although the increased access to highly active antiretroviral therapy (HAART) has led to a reduction in HIV-associated opportunistic infections and mortality, the concurrent management of HIV/TB co-infection remains a challenge owing to adverse effects, complex drug interactions, overlapping toxicities and tuberculosis -associated immune reconstitution inflammatory syndrome. Several hypotheses have been put forward for the exacerbation of tuberculosis by HIV and vice versa supported by immunological studies. Discussion on the mechanisms produced by infectious cofactors with impact on disease pathology could shed light on how to design potential interventions that could decelerate disease progression. With no vaccine for HIV and lack of an effective vaccine for tuberculosis, it is essential to design strategies against HIV-TB co-infection.

Cryptococcosis: epidemiology, fungal resistance, and new alternatives for treatment

Cryptococcosis is an important systemic mycosis and the third most prevalent disease in human immunodeficiency virus (HIV)-positive individuals. The incidence of cryptococcosis is high among the 25 million people with HIV/acquired immunodeficiency syndrome (AIDS), with recent estimates indicating that there are one million cases of cryptococcal meningitis globally per year in AIDS patients. In Cryptococcus neoformans, resistance to azoles may be associated with alterations in the target enzyme encoded by the gene ERG11, lanosterol 14α-demethylase. These alterations are obtained through mutations, or by overexpressing the gene encoding. In addition, C. gattii and C. neoformans present a heteroresistance phenotype, which may be related to increased virulence. Other species beyond C. neoformans and C. gattii, such as C. laurentii, have been diagnosed mainly in patients with immunosuppression. Infections of C. albidus have been isolated in cats and marine mammals. Recent evidence suggests that the majority of infections produced by this pathogen are associated with biofilm growth, which is also related with increased resistance to antifungal agents. Therefore, there is a great need to search for alternative antifungal agents for these fungi. The search for new molecules is currently occurring from nanoparticle drugs of plant peptide origin. This article presents a brief review of the literature regarding the epidemiology of cryptococcosis, as well as fungal resistance and new alternatives for treatment.

Solitary cavitary pulmonary nodule may be a common CT finding in AIDS-associated pulmonary cryptococcosis

BACKGROUND

Previous studies have demonstrated that the most common chest radiologic finding in acquired immune deficiency syndrome (AIDS)-associated pulmonary cryptococcosis (PC) is diffuse interstitial infiltrates. The aim of this study was to provide additional radiologic characterization of PC in AIDS patients.

METHODS

AIDS patients from the Second Affiliated Hospital of the Southeast University who were diagnosed with cryptococcosis between February 2009 and May 2012 and who had undergone chest computed tomography (CT) scans before or at the time of diagnosis were retrospectively analyzed.

RESULTS

Twelve patients met eligibility criteria. The median CD4 T-cell count was 23 cells/μl (range 2-79 cells/μl). Eleven patients had pulmonary abnormalities on imaging. Initial chest CT scans demonstrated solitary cavitary pulmonary nodules in 9 patients, pleural effusions in 2 patients, bilateral ground-glass opacities in 6 patients, patchy opacities in 1 patient, and bronchiectasis in 1 patient. Bilateral ground-glass opacities appeared to be associated with Pneumocystis pneumonia, while the presence of a pleural effusion was predictive of PC. Of the 9 solitary cavitary pulmonary nodules, 7 were PC and the other 2 were probable cases of PC. These nodules were predominantly in the peripheral lung and were either asymptomatic or caused only mild pulmonary symptoms.

CONCLUSIONS

Solitary cavitary pulmonary nodule may be a common CT finding in AIDS-associated PC. All AIDS patients with solitary cavitary pulmonary nodules on chest CT should be screened for Cryptococcus infection.

Cryptococcus laurentii biofilms: structure, development and antifungal drug resistance

A great number of fungal infections are related to biofilm formation on inert or biological surfaces, which are recalcitrant to most treatments and cause human mortality. Cryptococcus laurentii has been diagnosed as the aetiological pathogen able to cause human infections mainly in immunosuppressed patients and the spectrum of clinical manifestations ranges from skin lesions to fungaemia. The effect of temperature, pH and surface preconditioning on C. laurentii biofilm formation was determined by 2, 3-bis (2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT) reduction assay. Scanning electron microscopic (SEM) analysis of C. laurentii biofilms demonstrated surface topographies of profuse growth and dense colonization with extensive polymeric substances around the cells. In this study, we determined the activity of amphotericin B, itraconazole and fluconazole against C. laurentii free-living cells and biofilms. The activity of antifungals tested was greater against free-living cells, but sessile cells fell into the resistant range for these antifungal agents. Extracellular polymeric substances (EPS), comprising the matrix of C. laurentii biofilms, were isolated by ultrasonication. Fourier transform infrared spectroscopy (FT-IR) was performed with ethanol-precipitated and dried samples. Also, the multielement analysis of the EPS was performed by inductively coupled plasma optical emission spectroscopy (ICP-OES).

Induction of Cryptococcus laurentii α-galactosidase

The surface activity of Cryptococcus laurentii α-galactosidase can be significantly (up to 80 times) influenced by a carbon source present in a cultivation medium. Induction of this enzyme is stimulated by the presence of saccharides containing bound galactose. The highest activity observed when the cells grew in a lactose medium was probably a consequence of the absence of cleavage products serving as repressors (glucose). This idea is supported by the poor growth of cells in the medium with lactose as the carbon source. The induction of surface α-galactosidase was accompanied by increased activities in cytosole. The membrane fraction also contained this enzyme, but the influence of the carbon source was not proportional. The induction of α-galactosidase may play an important role in galactose metabolism of the genus Cryptococcus with a direct influence on the virulence of these capsular yeasts.

Antifungal susceptibility, enzymatic activity, PCR-fingerprinting and ITS sequencing of environmental Cryptococcus laurentii isolates from Uberaba, Minas Gerais, Brazil

Cryptococcus laurentii has been classically considered a saprophytic species, although several cases of human infection have been already reported. This study aimed to evaluate the phospholipase, proteinase and hemolysins activity, the antifungal susceptibility profile, the genetic variability by M13 and (GACA)(4) fingerprinting and the internal transcribe spacer (ITS) sequencing of 38 C. laurentii isolates recovered from captive bird droppings and surrounding hospital areas. All of them exhibited phospholipase activity, while the hemolytic activity was evidenced in 34 (89.4%) isolates. None of them exhibited proteinase activity. Twenty-seven isolates (71.1%) presented susceptibility dose dependent to fluconazole. Most isolates (94.7%) were susceptible to voriconazole, while one (2.65%) was resistant to this drug. Twenty-one (55.3%) isolates showed reduced susceptibility to itraconazole while nine (23.7%) were resistant. Three (7.9%) and five (13.1%) isolates exhibited resistance to ketoconazole and amphotericin B, respectively. Most C. laurentii fingerprinting obtained with M13 and (GACA)(4) showed high heterogeneity. By using the two primers, seven (18.4%) isolates grouped as A (CL2, CL7, and CL8), B (CL35, CL38) and C (CL29, CL30) with 100% similarity. Different from most variable surrounding hospital isolates, all but one of the pet shops strains clustered with the two primers, although they had been recovered from different neighborhoods. All isolates were identified as C. laurentii phylogenetic group I by ITS sequencing. Thus, the presence of virulence factors, a decreased antifungal susceptibility and a heterogeneous molecular pattern of the C. laurentii isolates here described suggests this species can be a potential pathogen in the context of the immunocompromised population.

Evaluation of the experimental inoculation of Cryptococcus albidus and Cryptococcus laurentii in normal mice: virulence factors and molecular profile before and after animal passage

The genus Cryptococcus includes free-developing species, a few of which are of medical importance. Some, such as C. neoformans and C. gattii, cause infections in man frequently and C. albidus and C. laurentii cause less so. The aims of this study were to evaluate organ colonization after inoculation of C. albidus and C. laurentii isolates in normal BALB/c mice, the virulence factors (growth at 37 degrees C, capsule, melanin, proteinase, and phospholipase production) and the molecular profile (PCR-fingerprinting) of the yeasts before and after infection. The importance of different profiles (virulence and molecular) was considered in relation to the distribution in different organs and to the time intervals of isolation from organs. C. albidus was isolated from animal organs 2 to 10 days after inoculation and C. laurentii from 2 to 120 days. Most isolates of the two species kept the virulence factors showed before inoculation. The high homogeneity of the molecular profile of C. albidus and the high heterogeneity of C. laurentii were kept through the passages in animals. It is concluded that most isolates of both species were recovered from the animal organs after 5 or more days, and phenotypes were not altered by inoculation. No molecular alteration was detected and the virulence factors were not related to the time intervals before isolation from organs.