Cryptococcal infections: changing epidemiology and implications for therapy

Minimizing the Risk of Donor-Derived Events and Maximizing Organ Utilization Through Education and Policy Development

Herein, we review the current knowledge of donor-derived disease and current US Organ Procurement and Transplantation Network policies to minimize the risk. During the process, we also consider actions to further mitigate the risk of donor-derived disease. The overarching goal is to provide an infectious disease perspective on the complex decision of organ acceptance for transplant programs and candidates.

Follow-Up of Surgical or Nonsurgical Patients with Pulmonary Cryptococcosis: A Real-World Study

Background

Surgical and medical treatments are applied to pulmonary cryptococcosis (PC) in the real world, while the prognosis of different therapies is uncertain. This study investigated diagnosis, real-world therapy, follow-up outcomes, and prognosis factors, aiming to deepen our understanding of PC.

Methods

Patients pathologically diagnosed with PC were retrospectively reviewed and followed up. Further comparisons and subgroup analyses were conducted in surgical and nonsurgical treatment individuals. Univariable and multivariable logistic regression methods were used to explore the risk factors associated with treatment failure.

Results

One hundred and sixty-three patients were included in this study, of whom 92 underwent surgical removal of VATS or open lung surgery (68 of them received postoperative antifungal treatment) and 71 got antifungal drugs only. Compared with nonsurgical patients, surgical patients were more immunocompetent (73 [79.3%] cases vs 33 [46.5%]), showed milder symptoms and more limited pulmonary lesions. Although they had instant treatment response owing to lesions resection, there is no significant advantage in the rate of treatment failure. Multivariable regression showed independent predictive factors associated with treatment failure were polymorphonuclear (PMN)>6.30*10⁹/L, albumin (Alb) <40g/L and antifungal dosage <400mg/d. Further analysis among patients with different immune statuses or symptoms demonstrated that sufficient antifungal dosage could reduce the rate of treatment failure.

Conclusion

PC showed variable and nonspecific clinical features. PC patients with limited nodules/masses and mild symptoms often led to misdiagnosis and unnecessary lung resections. The potential risk factors including higher PMN and hypoalbuminemia could help clinicians to identify PC patients with poor treatment efficiency at an early stage. To note, sufficient antifungal dosage may improve the treatment outcomes.

Characteristics of pulmonary cryptococcosis in patients with rheumatoid arthritis

Background and objective

A high frequency of infections complicating rheumatoid arthritis (RA) has been reported due to the immunomodulatory effect of RA or to agents with immunosuppressive effects used in its treatment. We aimed to assess clinical and radiological characteristics of pulmonary cryptococcosis in patients with and without RA.

Methods

We retrospectively reviewed the medical records of 52 patients with pulmonary cryptococcosis and divided them into two groups, those with RA and without RA, and compared clinical characteristics and radiological findings between them.

Results

Eleven (21.2%) of the 52 patients had RA. Median follow-up periods were 51.2 (range: 1.1–258.7) months for patients with RA and 19.1 (range: 0.63–246.9) months for patients without RA. Among the patients with RA, 81.8% were women, with a mean age of 68.1 years. Female sex and respiratory comorbidities were significantly more frequent in patients with RA than in patients without RA. Frequencies of concomitant cryptococcal meningitis and respiratory failure were not different between the groups. There were no significant differences in frequency of any radiological findings, locations and number between the two groups. Among patients with RA, all but one responded well to antifungal treatment. During the antifungal treatment course, one (9.1%) patient with RA died of cryptococcosis. Despite continuing antirheumatic drugs, no patients had recurrence of pulmonary cryptococcosis during follow-up.

Conclusion

Other than some differences in background, there were no clinical, radiological or prognostic differences between the patients with and without RA with pulmonary cryptococcosis. The administration of antirheumatic therapy had no negative effect on the clinical course of antifungal treatment.

Changing demographics and risk factors for cryptococcosis: A 12-year review at a tertiary care centre

BACKGROUND

Cryptococcosis is classically associated with the immunocompromised patients but there is a rising appreciation for its impact on the immunocompetent hosts. We sought to analyse the trends, diagnosis, treatment of different hosts and the effect of immunodeficiency and chronic liver disease on relapse and in-house mortality.

METHODS

This is a retrospective study of 12 years of patients with cryptococcosis, divided into three different groups: HIV-infected, transplant and non-HIV non-transplant (NHNT). Data were analysed with Chi-square, unpaired parametric t test, simple and multivariate logistic regression analysis.

RESULTS

Of 114 identified patients, 23 (20.2%) had HIV infection, 11 (9.6%) had transplant, 80 (70.2%) were NHNT patients. Overall, mortality was 28.1% (32/114) and relapse occurred in 10.5% (12/114) of patients. The mortality trend was higher (OR = 2.346, p = .287) in the transplant group (45.5%, 5/11) than in HIV (26.1%, 6/23) and NHNT groups (26.3%, 21/80). HIV was associated with relapse; 30.4% (7/23) for HIV-positive patients and 5.5% (5/91) for HIV-negative patients (OR = 7.525, p = .002). Chronic liver disease had a large and statistically significant association with mortality on multivariate analysis (OR = 3.583, p = .013) which was more pronounced than the HIV or transplant groups. It was independently associated with mortality by chi-square analysis (OR 3.137, p = .012).

CONCLUSION

Chronic liver disease represented 30.7% (35/114) of all studied patients. It was a risk factor for in-hospital mortality. HIV infection and transplant were not statistically significant for mortality. Relapse was highest in the HIV-infected patients at 30.4% (7/23). These data highlight the effect of type and degree of immunocompromise on cryptococcosis.

Fungal Infections of the Gastrointestinal Tract

The thinking about fungi has evolved from unusual agents considered contaminants and colonizers to actual pathogens. Fungi are ubiquitous in nature and are found throughout in association with food, soil, mammals, and insects. Fungi have become important pathogens in animals and humans causing infections extending from superficial disease to disseminated infection. Because the gastrointestinal tract is continually exposed to fungi, it is frequently colonized and infected by numerous yeast and other fungi. It is also the origin of many disseminated fungal infections. The increased incidence of fungal infections has led to the approval and use of novel antifungals.

Frequency of Invasive Fungal Disease in Adults: Experience of a Specialized Laboratory in Medellín, Colombia (2009-2015)

Invasive fungal diseases (IFD) contribute significantly to worldwide morbidity and mortality, but their frequency is not well-described in some countries. The present work describes the frequency of IFD in a specialized laboratory in Colombia. A retrospective, descriptive study was implemented between March 2009 and December 2015. Results: 13,071 patients with clinical suspicion of IFD were referred during the study period, from which 33,516 biological samples were processed and analyzed using 14 laboratory methods. Diagnosis was confirmed in 1425 patients (11%), distributed according to the mycoses of interest analyzed here: histoplasmosis in 641/11,756 patients (6%), aspergillosis in 331/10,985 patients (3%), cryptococcosis in 239/8172 patients (3%), pneumocystosis in 111/1651 patients (7%), paracoccidioidomycosis in 60/10,178 patients (0.6%), and invasive candidiasis in 48/7525 patients (0.6%). From the first year of the study period to the last year, there was a 53% increase in the number of cases of IFD diagnosed. Our laboratory experienced a high frequency of IFD diagnosis, possibly attributable to the availability of a greater range of diagnostic tools. Frequency of IFD in this study was atypical compared with other studies, probably as a result of the single laboratory-site analysis. This demonstrates that implementing educational strategies helps to create a high index of clinical suspicion, while the availability and utilization of appropriate diagnostic assays assure greater reliability in identification of these cases.

Evaluation of low cryptococcal antigen titer as determined by the lateral flow assay in serum and cerebrospinal fluid among HIV-negative patients: a retrospective diagnostic accuracy study

Cryptococcosis is one of the most common opportunistic infections in both immunocompetent and immunocompromised hosts. Although the cryptococcal antigen (CrAg) lateral flow assay (LFA) has been widely used in clinical settings due to its high sensitivity and specificity, the diagnostic value of a low CrAg LFA titers remains unclear. In this study, we performed a retrospective analysis of 149 HIV-negative patients with low CrAg LFA titers (≤1:10) in a Chinese tertiary hospital from January 2013 to December 2017, to evaluate the diagnostic value of low CrAg LFA titers in serum and cerebrospinal fluid (CSF) at different thresholds. Sensitivity and specificity of low CrAg LFA titers in patients with definitive diagnoses of cryptococcosis were 39.6% (95% CI, 29.7–50.1%) and 100% (95% CI, 69.2–100%), respectively, at a threshold of 1:10 in serum. A sensitivity of 72.9% (95% CI, 62.9–81.5%) and a decreased specificity of 70.0% (95% CI, 34.8–93.3%) were observed at a threshold of 1:5 in serum. No false-positive cases were identified in patients with low CrAg titers in CSF and all positive predictive values (PPVs) were 100%. Among the cases with low serum CrAg titers, lumbar puncture was performed in 97 patients and positive CSF CrAg titers were reported in 6 patients. In conclusion, the results of this study imply that low CrAg LFA titer, either in serum or CSF, is crucial for early diagnosis of cryptococcosis in HIV-negative patients, and lumbar puncture is recommended to be performed routinely for CSF testing when a positive low serum titer is reported. Cryptococcal meningitis should be considered seriously when the CSF CrAg titer is positive.

An exceptional case report of disseminated cryptococcosis in a hitherto immunocompetent patient

Cryptococcosis is an opportunistic fungal infection causes significant disease predominantly in immunocompromised patients. Here we present an excepcional case of disseminated cryptococcosis with pulmonary and cerebral involvement in an immunocompetent patient with no apparent predisposing factors at the time of hospital admission. We described a case of an apparently immunocompetent 66-years old man admitted to hospital with a one-month history of cough, fever and vertigo. During hospitalization, thorax imaging was suggestive of lung metastasis, therefore, he went through several investigations. During hospitalization, he developed neurological symptoms and subsequently underwent a lumbar puncture. Cerebrospinal fluid (CSF) culture was positive for Cryptococcus spp. isolated on Sabouraud's dextrose agar and bird seed agar. In addition, the direct microscopy examination was positive for the India ink test, as well as with the latex agglutination test for cryptococcal polysaccharide antigen (CrAg) in CSF, while serum CrAg was negative. Despite the absence of classic immunocompromising features, he was treated with amphotericin B and fluconazole due to suspected disseminated cryptococcal infection. Later, he was diagnosed with prostatic adenocarcinoma. Upon successful completion of treatment for disseminated cryptococcosis, the patient underwent radical prostate ablation surgery as a treatment forprostatic adenocarcinoma. This exceptional case emphasizes the high degree of suspicion of atypical infections, and in these cases, it is particularly important to consider fungal infections in hitherto healthy patients with no apparent predisposing factors. Although Cryptococcus spp. is predominantly reported in patients with hematological malignancies, cryptococcosis investigation should also be considered as part of the initial workup of patients with a new diagnosis of a solid tumour prior to chemotherapy or radiotherapy.

Cryptococcosis in solid organ transplantation-Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of cryptococcosis in the pre- and post-transplant period. The current update now includes a discussion of cryptococcosis, which is the third most common invasive fungal infection in SOT recipients. Infection often occurs a year after transplantation; however, early infections occur and donor-derived infections have been described within 3 months after transplant. There are two main species that cause infection, Cryptococcus neoformans and C gattii. Clinical onset may be insidious, but headaches, fevers, and mental status changes should warrant diagnostic testing. The lateral flow cryptococcal antigen assay is now the preferred test from serum and cerebrospinal fluid due to its rapidity, accuracy, and cost. A lumbar puncture with measurement of opening pressure is recommended for patients with suspected or proven cryptococcosis. Lipid amphotericin B plus 5-flucytosine is used as initial treatment of meningitis, disseminated infection, and moderate-to-severe pulmonary infection, followed by fluconazole as consolidation therapy. Fluconazole is effective for mild-to-moderate pulmonary infection. Immunosuppression reduction as part of management may lead to immune reconstitution syndrome that may resemble active disease.

Comparative study of primary pulmonary cryptococcosis with multiple nodules or masses by CT and pathology

The manifestations of pulmonary cryptococcosis with multiple nodules or masses on computed tomography (CT) are diverse and difficult to differentiate from those of lung cancer and pulmonary tuberculosis. The present study compared the multislice spiral CT signs with pathological results and used the pathological results to explain the CT signs with the aim of improving the accuracy of the diagnosis of this disease. A retrospective analysis of 20 patients with primary pulmonary cryptococcosis with multiple nodules or masses was performed. Based on the CT signs, eight patients had been misdiagnosed with lung cancer accompanied by intrapulmonary metastasis andthree patients had been misdiagnosed with tuberculosis. The major CT manifestations were a cluster of nodules or masses located within 2 cm below the pleura and distributed along the bronchi. A total of nine patients had primary lesions with diameters of 1.1–2.0 cm and 12 patients had satellite lesions with diameters of 0.1–1.0 cm. Regarding treatment, 5 patients underwent surgical monotherapy, 12 patients underwent antifungal monotherapy and three patients received surgery in combination with antifungal therapy. HE staining indicated that Cryptococcus neoformans was engulfed by macrophages, which were surrounded by massive infiltrating lymphocytes and a large amount of fibrous tissue, which formed multinucleated macrophages or granulomas. Periodic acid-Schiff staining was positive and acid fast staining was negative. In conclusion, comparison of CT signs with the pathological manifestation of pulmonary cryptococcosis with multiple nodules or masses indicated that the pathological results may explain certain imaging signs. Combination of CT and pathological examination may provide a deeper understanding of this disease and improve the accuracy of its diagnosis.

Disseminated Cryptococcosis With Severe Increased Intracranial Pressure Complicated With Cranial Nerve Palsy in a Child

Cryptococcosis is less common in children than in adults but remains an important cause of pneumonia and meningoencephalitis in both immunocompromised and immunocompetent patients. Intracranial hypertension commonly complicates cryptococcal meningitis and may cause significant visual and neurologic morbidity and mortality. Early and aggressive management of intracranial hypertension in accordance with established guidelines reduces the risk of long-term complications and death. In this case report, we present a 12-year-old girl with cryptococcal meningitis, pneumonitis and dermatitis complicated with cranial nerve palsy and loss of vision. She was successfully treated with serial cerebrospinal fluid drainage, antifungal and interferon gamma therapy.

Molecular Characterization and Antifungal Susceptibility Testing of Sequentially Obtained Clinical Cryptococcus deneoformans and Cryptococcus neoformans Isolates from Ljubljana, Slovenia

AIM

To retrospectively investigate the epidemiology of cryptococcosis in Ljubljana, Slovenia.

METHODOLOGY

Forty-six sequentially obtained isolates from 19 patients were subjected to amplified fragment length polymorphism (AFLP) genotyping, microsatellite typing, mating- and serotype PCRs and antifungal susceptibility testing.

RESULTS

Majority of the isolates were Cryptococcus deneoformans (n = 29/46; 63%) followed by Cryptococcus neoformans (n = 16/46; 34.8%) and their interspecies hybrid (n = 1/46; 2.2%). Mating-type α was predominant, two mating-type a C. deneoformans isolates and one mating-type a/α isolate were observed. Several mixed infections were found by microsatellite typing; one patient had a persisting C. deneoformans infection for > 2.5 years. For C. deneoformans, the in vitro antifungal MIC₉₀ and susceptibility ranges were for amphotericin B 0.25 µg/ml (0.031-0.25 µg/ml), 5-fluorocytosine 0.25 µg/ml (0.063-4 µg/ml), fluconazole 8 µg/ml (0.5-16 µg/ml), voriconazole 0.063 µg/ml (0.008-0.125 µg/ml), posaconazole 0.063 µg/ml (0.008-0.063 µg/ml) and itraconazole 0.063 µg/ml (0.031-0.125 µg/ml). For C. neoformans, these values were for amphotericin B 0.25 µg/ml (0.063-0.5 µg/ml), 5-fluorocytosine 1 µg/ml (0.063-1 µg/ml), fluconazole 16 µg/ml (0.5-64 µg/ml), voriconazole 0.125 µg/ml (0.008-0.25 µg/ml), posaconazole 0.063 µg/ml (0.008-0.063 µg/ml) and itraconazole 0.063 µg/ml (0.031-0.125 µg/ml).

CONCLUSIONS

Majority of the cases were caused by C. deneoformans; mating-type α was predominant. Several mixed infections were identified by AFLP genotyping and microsatellite typing. Despite antifungal therapy, a cryptococcal isolate could persist for years. Voriconazole, itraconazole and posaconazole were the most potent antifungal drugs.

[Molecular characterization of Cryptococcus neoformans isolates from HIV patients, Guayaquil, Ecuador]

INTRODUCTION

Neurocryptococcosis is an opportunistic fungal infection that represents a high cost in human lives and for the economy of countries. Its causative agent, the Cryptococcus neoformans/Cryptococcus gattii species complex, has a sexual and an asexual phase, four major serotypes and seven molecular varieties with phenotypic, clinical-epidemiological and antifungal susceptibility differences.

OBJECTIVE

To characterize by molecular methods clinical isolates of C. neoformans from Guayaquil, Ecuador.

MATERIALS AND METHODS

We determined mating types, serotypes and molecular varieties by PCR and RFLP in 27 yeast isolates previously identified as C. neoformans by conventional methods. The isolates were recovered from cerebrospinal fluid of HIV seropositive patients with neurological syndrome admitted at "Dr. José Daniel Rodríguez Maridueña" Hospital from December, 2013, to January, 2015.

RESULTS

We established a wide prevalence of C. neoformans serotype A, MATα and genotype VNI among the studied isolates.

CONCLUSIONS

These data are similar to those obtained in other countries and the first identified by molecular characterization in Guayaquil, Ecuador. Therefore, they constitute an important contribution to the knowledge on cryptococcosis in this country.

Epidemiology of Cryptococcosis and Cryptococcal Meningitis in a Large Retrospective Cohort of Patients After Solid Organ Transplantation

BACKGROUND

Cryptococcosis is the third most common invasive fungal infection in solid organ transplant (SOT) recipients. There are no nationally representative data describing the incidence, risk factors, and outcomes of cryptococcosis after SOT.

METHODS

We assembled a large cohort of adult SOT recipients using Classification of Diseases, Ninth Revision, Clinical Modification billing data from Healthcare Cost and Utilization Project State Inpatient Databases of Florida (2006-2012), New York (2006-2011), and California (2004-2010). Demographics, comorbidities, death, and cryptococcal infections coded during hospitalization were identified.

RESULTS

A total of 42634 adults with SOT were identified during the study period. Cryptococcal disease was identified in 0.37% (n = 158), 44% of which had meningitis (n = 69). Median time to diagnosis of cryptococcosis was 464 days (range, 4-2393). The median time to onset of cryptococcosis was earlier for lung (191 days; range, 7.5-1816), heart (195 days; range, 4-1061), and liver (200 days; range, 4-1581) compared with kidney transplant recipients (616 days; range, 12-2393; P < .001, log rank test). Very early-onset disease (<30 days after transplantation) more frequently occurred in liver and lung transplant recipients. Lung transplant recipients had the highest risk of cryptococcosis (hazard ratio [HR], 2.10; 95% confidence interval [CI], 1.21-3.60). Cryptococcosis was associated with death (HR, 2.29; 95% CI, 1.68-3.11), after adjusting for age, type of SOT, and other comorbidities.

CONCLUSIONS

Cryptococcosis is rare after SOT, but it is associated with significantly increased risk of death. Lung transplant recipients are at highest risk for cryptococcosis among SOTs. Nonkidney transplants have earlier onset of cryptococcosis and higher risk of death compared with kidney transplant recipients.

End-Stage Liver Disease Is a Strong Predictor of Early Mortality in Cryptococcosis

Background.  Cryptococcosis in the setting of end-stage liver disease (ESLD) has been associated with high mortality. We sought to compare the outcome of cryptococcal disease in patients with ESLD to that of human immunodeficiency virus (HIV)-positive patients and to those patients without HIV or ESLD. Methods.  We assembled a retrospective cohort of 232 consecutive cases of cryptococcosis in our institution, from 2002 to 2014, inclusively. We analyzed the cases for comorbidities, type of infection, and survival. Data were analyzed with t tests, Fishers Exact test, and Kaplan-Meyer analysis. Results.  Twenty-five (10.8%) patients with cryptococcal infection had concomitant ESLD; of these, 5 (20%) presented with peritonitis. Most (17 of 25, 68%) did not have any other cause of immunocompromise that has been more classically associated with cryptococcosis. Patients with ESLD had a significantly higher mortality than HIV-positive patients and HIV-negative patients without ESLD (HIVNE) (80% vs 13.6% and 22.7%, respectively; P < .001). In addition, fatal outcome in ESLD patients occurred more rapidly than in HIVNE patients, with a median survival of 6 days (vs 17), despite a comparable time to diagnosis (6.2 vs 6.6 days). Conclusions.  Cryptococcosis is an important morbidity in patients with ESLD. Patients with ESLD who are infected with Cryptococcus have a high and rapid mortality. This suggests that a high level of vigilance for cryptococcal infection should be kept in patients with ESLD.

Abdominal Lymphonodular Cryptococcosis in an Immunocompetent Child

We describe our experience with an apparently immunocompetent child presenting with pyrexia of unknown origin without focal signs. Investigations revealed lymphadenopathy at lung hila, mesentery, and porta hepatis. The child had received at least two months of empiric antituberculous therapy (ATT) before she came to us. A CT-guided biopsy revealed granulomatous inflammation. PAS stain showed yeasts which stained blue with Alcian blue, suggesting C. neoformans.

How Cryptococcus interacts with the blood-brain barrier

Cryptococcus demonstrates predilection for invasion of the brain, but the mechanism by which Cryptococcus crosses the blood-brain barrier (BBB) to cause brain invasion is largely unknown. In order for Cryptococcus to cross the BBB, there must be a way to either cross human brain microvascular endothelial cells, which are the main constitute of the BBB, or go in between tight junctions. Recent evidence of human brain microvascular endothelial cell responses to transcellular brain invasions includes membrane rearrangements, intracellular signaling pathways and cytoskeletal activations. Several Cryptococcal genes related to the traversal of BBB have been identified, including CPS1, ITR1a, ITR3c, PLB1, MPR1, FNX1 and RUB1. In addition, Cryptococcus neoformans-derived microvesicles may contribute to cryptococcal brain invasion. Paracellularly, Cryptococcus may traverse across BBB using either routes utilizing plasmin, ammonia or macrophages in a Trojan horse mechanism.

Systemic Review of Published Reports on Primary Cutaneous Cryptococcosis in Immunocompetent Patients

Primary cutaneous cryptococcosis (PCC) has been confirmed as a distinct clinical entity with secondary cutaneous cryptococcosis from systematic infection since 2003. Although it has been confirmed as a distinct clinical entity, little has progressed on PCC in immunocompetent hosts compared to their immunocompromised counterpart. We reviewed the literature on cases of PCC in immunocompetent patients from 2004 to 2014, and 21 cases from 16 reports were identified. Males are more likely to develop PCC infections, with a ratio of 17:4 male to female. These patients were found to be almost all senior population except for patients from Asia. Asymptomatic or moderate itching manifesting in a painful nodule is the most common presentation, although there is no typical clinical manifestation recorded. Upper limbs are the most common site of infection, accounting for 71.4 % of all patients. Of the 12 identified isolates, 6 strains are identified as C. neoformans, 5 as C. gattii, and 1 as C.laurentii. Fluconazole was used in 10 cases; however, only 80 % of the 10 cases could confirm that fluconazole was effective in clearing the infections. Interestingly although not approved as a treatment option, Itraconazole was effective in the seven cases it was used to treat cryptococcosis, with a dosage range of 100-400 mg/d and duration from 3 to 6 months. Even though the prognosis of these patients was generally good, more data are need to determine which antifungal azole is the better treatment option and whether primary skin infections could disseminate to systematic infection.

A rare case of Cryptococcus gattii pneumonia in a renal transplant patient

Cryptococcus neoformans and Cryptococcus gattii are environmental fungi that can cause fever, cough, pneumonia, meningoencephalitis, dissemination, and death. C. gattii causes cryptococcomas more frequently than does C. neoformans and may require prolonged antifungal treatment. We present a rare case of C. gattii pneumonia in a renal transplant patient. A 44-year-old man, living in a rural area endemic for C. gattii and who had received a kidney transplant, was admitted to the hospital with fever, vomiting, weight loss, and diarrhea. A chest computed tomography revealed 2 alveolar, nodular, subpleural infiltrates in the periphery of the lungs. Differential diagnoses included infectious infiltrates, granulomatosis, embolization, and hemorrhage. C. gattii, molecular type VGI, was confirmed on day 28. Treatment consisted of amphotericin B at 1 mg/kg/day or fluconazole at 800 mg/day for first 6 weeks, followed by fluconazole at 400 mg/day for the subsequent 12 months. Response to the therapy has been slow. Because of the occurrence of outbreaks and its high morbidity and mortality rates, physicians must be aware of this complication in transplant recipients to avoid delays in diagnosis and to provide prompt management.

Current trends in the prevalence of Cryptococcus gattii in the United States and Canada

The incidence of Cryptococcus gattii infections in both Canada and the United States (US) is provided in this literature review beyond the British Columbia (BC) outbreak (1999-2013). Based on a search of the literature, case reports of C. gattii human infections including the prevalent molecular genotypes causing these infections in both Canada and the US have been documented since the C. gattii outbreak in BC. The literature reveals that: i) although C. gattii infections continue to be reported in both countries, the preliminary overall number of confirmed C. gattii infections may be decreasing in both Canada and the US (~23 cases each in 2012 versus ~17 and 20 cases, respectively in 2013); ii) C. gattii genotype distribution is region-dependent; iii) C. gattii is more frequently isolated from infections in the immunocompromised host (including acquired immune deficiency syndrome [AIDS] infection) than previously expected; iv) although pulmonary disease is higher than in C. neoformans infections, central nervous system disease is also reported among patients infected with C. gattii.

Molecular epidemiology of Cryptococcus neoformans and Cryptococcus gattii in China between 2007 and 2013 using multilocus sequence typing and the DiversiLab system

The purpose of this study was to investigate the molecular characteristics of 83 clinical Cryptococcus neoformans/C. gattii species complex isolated in Beijing, China, between 2007 and 2013. Restriction fragment length polymorphism of the gene URA5 (URA5-RFLP), multilocus sequence typing (MLST), and automated repetitive polymerase chain reaction (rep-PCR; DiversiLab system) were performed to genotype these cryptococcal isolates. There was an excellent correlation amongst the three methods; however, PU157 was assigned as VNII according to URA5-RFLP, while it was classified as VNI by the DiversiLab system analysis. PU157 was finally identified as VNB by seven-locus MLST analysis. Moreover, though AD hybrids could not be processed by MLST, ideal results could be obtained by the DiversiLab system. The genotype VNI accounted for 95.2% (79/83) of isolates. Besides one strain of VNB, VNIII, and VGI each, a strain of VGII was detected in our study, which was isolated from a patient from the temperate region in North China. In addition, the most common MLST sequence type (ST) was ST5, accounting for 91.6% (76/83), followed by ST31, ST63, ST182, ST295, ST296, and ST332. ST295, ST296, and ST332 were new STs. Except for isolate PU157 (VNB), identical results were obtained quickly and accurately through the DiversiLab system compared to MLST and URA5-RFLP. The discovery of VNB and VGII in the temperate climate regions of China suggested that the population structure of C. neoformans and C. gattii should be explored more extensively. Our results also showed that the DiversiLab system can be used in the genotyping of C. neoformans and C. gattii.

Mannoprotein MP84 mediates the adhesion of Cryptococcus neoformans to epithelial lung cells

The capsule is the most important virulence factor of the fungal pathogen Cryptococcus neoformans. This structure consists of highly hydrated polysaccharides, including glucuronoxylomannan (GXM), and galactoxylomannan (GalXM). It is also composed of mannoproteins (MPs) which corresponds to less than 1% of the capsular weight. Despite MPs being the minority and least studied components, four of these molecules with molecular masses of 115, 98, 88, and 84 kDa were identified and characterized as C. neoformans immunoreactive antigens involved in the pathogenesis, and are potential cryptococcosis vaccine candidates. With the aim to describe the adhesive property of MPs, we cloned and expressed the MP84, a mannoprotein with molecular weight of 84 kDa, on Pichia pastoris yeast, and performed interaction assays of C. neoformans with epithelial lung cells, in the presence or absence of capsule components. Two fungal strains, the wild type, NE-241, and a mutant, CAP67, deficient in GXM production, were used throughout this study. The adhesion assays were completed using epithelial lung cells, A549, and human prostate cancer cells, PC3, as a control. We observed that capsulated wild type (NE-241), and acapsular (CAP67) strains adhered significantly to A549 cells, compared with PC3 cells (p < 0.05). GXM inhibits the NE-241 adhesion, but not the CAP67. In contrast, CAP67 adhesion was only inhibited in the presence of MP84. These results demonstrate the involvement of MP in the adhesion of C. neoformans to epithelial lung cells. We conclude that this interaction possibly involves an adhesion-like interaction between MP on the fungal surface and the complementary receptor molecules on the epithelial cells.