Pulmonary Cryptococcosis in the Immunocompetent Patient-Many Questions, Some Answers

Construction and validation of a nomogram model to predict the poor prognosis in patients with pulmonary cryptococcosis

Background

Patients with poor prognosis of pulmonary cryptococcosis (PC) are prone to other complications such as meningeal infection, recurrence or even death. Therefore, this study aims to analyze the influencing factors in the poor prognosis of patients with PC, so as to build a predictive nomograph model of poor prognosis of PC, and verify the predictive performance of the model.

Methods

This retrospective study included 410 patients (78.1%) with improved prognosis of PC and 115 patients (21.9%) with poor prognosis of PC. The 525 patients with PC were randomly divided into the training set and validation set according to the ratio of 7:3. The Least Absolute Shrinkage and Selection Operator (LASSO) algorithm was used to screen the demographic information, including clinical characteristics, laboratory test indicators, comorbidity and treatment methods of patients, and other independent factors that affect the prognosis of PC. These factors were included in the multivariable logistic regression model to build a predictive nomograph. The receiver operating characteristic curve (ROC), calibration curve and decision curve analysis (DCA) were used to verify the accuracy and application value of the model.

Results

It was finally confirmed that psychological symptoms, cytotoxic drugs, white blood cell count, hematocrit, platelet count, CRP, PCT, albumin, and CD4/CD8 were independent predictors of poor prognosis of PC patients. The area under the curve (AUC) of the predictive model for poor prognosis in the training set and validation set were 0.851 (95% CI: 0.818-0.881) and 0.949, respectively. At the same time, calibration curve and DCA results confirmed the excellent performance of the nomogram in predicting poor prognosis of PC.

Conclusion

The nomograph model for predicting the poor prognosis of PC constructed in this study has good prediction ability, which is helpful for improving the prognosis of PC and further optimizing the clinical management strategy.

Pulmonary cryptococcosis coexisting with lung adenocarcinoma: A case report and review of the literature

Pulmonary cryptococcosis (PC) is an invasive pulmonary fungal disease caused by Cryptococcus neoformans or Cryptococcus gattii. It often presents as a single nodule or mass on radiology, which is easily misdiagnosed as lung cancer or metastases. However, cases of PC coexisting with lung cancer are rare and when this scenario is encountered in clinical practice, it is easy to be misdiagnosed as metastatic lung cancer. The present study reported the case of a 65-year-old immunocompetent patient with PC coexisting with lung adenocarcinoma. Percutaneous lung biopsy was performed on the nodule in the anterior segment of the left upper lobe and the nodule in the posterior basal segment of the left lower lobe, which were diagnosed as primary adenocarcinoma and cryptococcus, respectively. Lung cancer was treated by surgery and PC was treated successfully by antifungal treatment. During the 5-year follow-up, contrast-enhanced CT showed no recurrence of either disease. This case reminds us of the possibility of dualism in the diagnosis of multiple pulmonary nodules based on CT examination, such as the coexistence of lung carcinoma and PC. In addition, early diagnosis and treatment contribute to good prognosis.

Serum sphingolipids aid in diagnosing adult HIV-negative patients with pulmonary cryptococcosis: a clinical cohort study

Background

Pulmonary cryptococcosis (PC) contributes to the ongoing global disease burden in human immunodeficiency virus (HIV)-negative populations. Since some PC patients are misdiagnosed under existing diagnostic guidelines, new diagnostic markers are needed to improve diagnostic accuracy and therapeutic efficacy and reduce disease risk.

Methods

Our previously established sphingolipidomic approach was employed to explore the use of serum sphingolipids (SPLs) in diagnosing HIV-negative patients with PC. A clinical cohort of PC, pulmonary aspergillosis (PA), and tuberculosis (TB) patients and healthy controls was assessed to identify SPL biomarkers.

Results

A total of 47 PC, 27 PA, and 18 TB patients and 40 controls were enrolled. PC and TB patients had similar clinical features, laboratory test results and radiological features, excluding plural effusion. The serum ceramide [Cer (d18:1/18:0)] level showed a significant increase in PC patients compared to controls and PA and TB patients (P<0.05). Cer (d18:1/18:0) was identified as a specific diagnostic biomarker for PC. The optimal cut-off value of greater than 18.00 nM showed a diagnostic sensitivity of 76.60% and a specificity of 95.00% and better distinguished PC patients from PA and TB patients. Furthermore, the serum Cer (d18:1/18:0) level gradually decreased after 3 and 6 months of treatment, suggesting the prediction potential for therapeutic efficacy of this biomarker. In addition, Cer (d18:1/18:0) analysis presented a higher sensitivity than the cryptococcal antigen (CrAg) assay.

Conclusions

This is the first study to report the use of the SPL Cer (d18:1/18:0) as a serum biomarker for diagnosing Cryptococcus spp. infection in HIV-negative patients.

Lesion size as a prognostic factor in the antifungal treatment of pulmonary cryptococcosis: a retrospective study with chest CT pictorial review of 2-year follow up

BACKGROUND

Pulmonary cryptococcosis (PC) is a fungal infection that can have a variable prognosis depending on several factors. The objective of this study was to analyse the characteristics of pulmonary lesions and identify prognostic factors in patients with PC who were human immunodeficiency virus (HIV) -negative and underwent antifungal treatment.

METHODS

The study enrolled patients diagnosed with PC who were negative for HIV. Symptoms, CT characteristics of pulmonary lesions, serum cryptococcal capsular antigen (CrAg) titre, underlying diseases, and duration of antifungal treatment were evaluated over a 2-year follow-up.

RESULTS

A total of 63 patients (40 men and 23 women) with a mean age of 50.4 years were included. Half of the patients (50.8%) were asymptomatic, and the most common symptoms were cough (44.4%), expectoration (27.0%), and fever (17.5%). Pulmonary lesions were mainly present in the peripheral and lower lobes of the lung, with 35 cases classified as nodular-type lesions and 28 cases classified as mass-type lesions. At the first, third, sixth, 12th, and 24th-month follow-ups, the median proportion of residual pulmonary lesions were 59.6%, 29.9%, 12.2%, 9.6%, and 0.0%, respectively. During antifungal treatment, the lesions of 33 patients achieved complete response, while the remaining 30 patients did not. Compared with the non-CR group, the CR group had a lower baseline serum CrAg titre (median, 1:20 vs 1:80, P < 0.01), smaller pulmonary lesion size (median area, 1.6 cm² vs 6.3 cm², P < 0.01), lower Hounsfield-units (HU) radiodensity (median, - 60.0 HU vs - 28.5 HU, P < 0.05), more nodular-type lesions (72.7% vs 36.7%, P < 0.01), and fewer air-bronchogram signs (18.2% vs 43.3%, P < 0.05). Multivariate logistic regression analysis showed that a larger lesion size on chest CT scans was associated with a lower likelihood of achieving complete response [OR: 0.89; 95% CI (0.81-0.97); P < 0.05].

CONCLUSIONS

PC was more commonly observed in HIV-negative men, and chest CT scans mostly revealed nodular-type lesions. After antifungal treatment, patients with smaller lesions had a better prognosis.

Epidemiology, management and outcomes of Cryptococcus gattii infections: A 22-year cohort

BACKGROUND

Cryptococcus gattii is a globally endemic pathogen causing disease in apparently immune-competent hosts. We describe a 22-year cohort study from Australia's Northern Territory to evaluate trends in epidemiology and management, and outcome predictors.

METHODS

A retrospective cohort study of all C. gattii infections at the northern Australian referral hospital 1996-2018 was conducted. Cases were defined as confirmed (culture-positive) or probable. Demographic, clinical and outcome data were extracted from medical records.

RESULTS

45 individuals with C. gattii infection were included: 44 Aboriginal Australians; 35 with confirmed infection; none HIV positive out of 38 tested. Multifocal disease (pulmonary and central nervous system) occurred in 20/45 (44%). Nine people (20%) died within 12 months of diagnosis, five attributed directly to C. gattii. Significant residual disability was evident in 4/36 (11%) survivors. Predictors of mortality included: treatment before the year 2002 (4/11 versus 1/34); interruption to induction therapy (2/8 versus 3/37) and end-stage kidney disease (2/5 versus 3/40). Prolonged antifungal therapy was the standard approach in this cohort, with median treatment duration being 425 days (IQR 166-715). Ten individuals had adjunctive lung resection surgery for large pulmonary cryptococcomas (median diameter 6cm [range 2.2-10cm], versus 2.8cm [1.2-9cm] in those managed non-operatively). One died post-operatively, and 7 had thoracic surgical complications, but ultimately 9/10 (90%) treated surgically were cured compared with 10/15 (67%) who did not have lung surgery. Four patients were diagnosed with immune reconstitution inflammatory syndrome which was associated with age <40 years, brain cryptococcomas, high cerebrospinal fluid pressure, and serum cryptococcal antigen titre >1:512.

CONCLUSION

C. gattii infection remains a challenging condition but treatment outcomes have significantly improved over 2 decades, with eradication of infection the norm. Adjunctive surgery for the management of bulky pulmonary C. gattii infection appears to increase the likelihood of durable cure and likely reduces the required duration of antifungal therapy.

Clinicoradiological Features of Pulmonary Cryptococcosis in Immunocompetent Patients

PURPOSE

To assess the clinicoradiological features of pulmonary cryptococcosis in immunocompetent patients.

MATERIALS AND METHODS

This retrospective study included immunocompetent patients who had been diagnosed with pulmonary cryptococcosis on the histopathologic exam and underwent chest CT between January 2008 and November 2019. Imaging features were divided into major imaging patterns, distributions, and ancillary imaging findings. Univariable analysis was performed to evaluate clinicoradiological features according to the presence of serum cryptococcal antigen.

RESULTS

Thirty-one patients were evaluated (mean age: 60 years, range: 19-78 years). A single nodular lesion confined to a single lobe was the most common imaging pattern (14/31, 45.2%). Serum cryptococcal antigen tests were performed in 19 patients (19/31, 61.3%). The presence of serum cryptococcal antigen was observed in six patients (6/19, 31.6%), all of whom showed a consolidation-dominant pattern. The presence of serum cryptococcal antigen was significantly associated with the consolidation-dominant pattern compared to those associated with a nodule-dominant pattern (p = 0.011).

CONCLUSION

A combination of CT findings of consolidation and a positive serum cryptococcal antigen test may be helpful for diagnosing pulmonary cryptococcosis in immunocompetent patients.

Comparative miRNA transcriptomics of macaques and mice reveals MYOC is an inhibitor for Cryptococcus neoformans invasion into the brain

Cryptococcal meningoencephalitis (CM) is emerging as an infection in HIV/AIDS patients shifted from primarily ART­naive to ART-experienced individuals, as well as patients with COVID-19 and immunocompetent hosts. This fungal infection is mainly caused by the opportunistic human pathogen Cryptococcus neoformans. Brain or central nervous system (CNS) dissemination is the deadliest process for this disease; however, mechanisms underlying this process have yet to be elucidated. Moreover, illustrations of clinically relevant responses in cryptococcosis are currently limited due to the low availability of clinical samples. In this study, to explore the clinically relevant responses during C. neoformans infection, macaque and mouse infection models were employed and miRNA-mRNA transcriptomes were performed and combined, which revealed cytoskeleton, a major feature of HIV/AIDS patients, was a centric pathway regulated in both infection models. Notably, assays of clinical immune cells confirmed an enhanced macrophage “Trojan Horse” in patients with HIV/AIDS, which could be shut down by cytoskeleton inhibitors. Furthermore, myocilin, encoded by MYOC, was found to be a novel enhancer for the macrophage “Trojan Horse,” and an enhanced fungal burden was achieved in the brains of MYOC-transgenic mice. Taken together, the findings from this study reveal fundamental roles of the cytoskeleton and MYOC in fungal CNS dissemination, which not only helps to understand the high prevalence of CM in HIV/AIDS but also facilitates the development of novel therapeutics for meningoencephalitis caused by C. neoformans and other pathogenic microorganisms.

Pulmonary Cryptococcosis

Pulmonary cryptococcosis describes an invasive lung mycosis caused by Cryptococcus neoformans or Cryptococcus gattii complex. It is often a high-consequence disease in both immunocompromised and immunocompetent populations, and may be misdiagnosed as pulmonary malignancy, leading to a delay in therapy. Epidemiology follows that of cryptococcal meningoencephalitis, with C. gattii infection more common in certain geographic regions. Diagnostic tools include histopathology, microscopy and culture, and the detection of cryptococcal polysaccharide antigen or Cryptococcus-derived nucleic acids. All patients with lung cryptococcosis should have a lumbar puncture and cerebral imaging to exclude central nervous system disease. Radiology is key, both as an adjunct to laboratory testing and as the initial means of detection in asymptomatic patients or those with non-specific symptoms. Pulmonary cryptococcomas (single or multiple) may also be associated with disseminated disease and/or cryptococcal meningitis, requiring prolonged treatment regimens. Optimal management for severe disease requires extended induction (amphotericin B and flucytosine) and consolidation therapy (fluconazole) with close clinical monitoring. Susceptibility testing is of value for epidemiology and in regions where relatively high minimum inhibitory concentrations to azoles (particularly fluconazole) have been noted. Novel diagnostic tools and therapeutic agents promise to improve the detection and treatment of cryptococcosis, particularly in low-income settings where the disease burden is high.

Cryptococcal Pneumonia in an Immunocompetent Patient: A Rare Occurrence

Cryptococcosis is an invasive yeast infection commonly found among immunosuppressed patients. Pulmonary cryptococcal infection can have variable presentations ranging from pulmonary nodules and masses to consolidation. A patient can present with shortness of breath, cough, sputum production, chest pain, fatigue, and weight loss. Diagnosis can be made using fungal culture, histology, radiographic findings, and cryptococcal antigen in serum as well as in the cerebrospinal fluid. Treatment is usually with a combination or a single antifungal agent. Few cases have been reported in immunocompetent individuals.

Here we present a case of 69-year-old immunocompetent individual, who was initially seen in the outpatient clinic for dyspnea, cough, and fatigue and was treated for pneumonia. The patient remained symptomatic despite multiple courses of oral antibiotics. He was then sent for inpatient admission. CT scan was obtained that showed patchy infiltrates and consolidations, followed by bronchoscopy. The cytology confirmed adenocarcinoma. The fungal smear and culture grew Cryptococcus neoformans. The patient was treated with fluconazole with improvement of his symptoms before starting chemotherapy.

We are reporting this case as clinicians usually focus on bacterial etiologies in outpatient setting. Our patient, who was immunocompetent, had a new diagnosis of cryptococcal pneumonia and was also found to have lung adenocarcinoma. This case highlights the rare occurrence of this type of pneumonia in immunocompetent patients and the importance of considering fungal causes of pneumonia in patients.

Cryptococcus neoformans releases proteins during intracellular residence that affect the outcome of the fungal-macrophage interaction

Cryptococcus neoformans is a facultative intracellular pathogen that can replicate and disseminate in mammalian macrophages. In this study, we analyzed fungal proteins identified in murine macrophage-like cells after infection with C. neoformans. To accomplish this, we developed a protocol to identify proteins released from cryptococcal cells inside macrophage-like cells; we identified 127 proteins of fungal origin in infected macrophage-like cells. Among the proteins identified was urease, a known virulence factor, and others such as transaldolase and phospholipase D, which have catalytic activities that could contribute to virulence. This method provides a straightforward methodology to study host-pathogen interactions. We chose to study further Yeast Oligomycin Resistance (Yor1), a relatively uncharacterized protein belonging to the large family of ATP binding cassette transporter (ABC transporters). These transporters belong to a large and ancient protein family found in all extant phyla. While ABC transporters have an enormous diversity of functions across varied species, in pathogenic fungi they are better studied as drug efflux pumps. Analysis of C. neoformans yor1Δ strains revealed defects in nonlytic exocytosis, capsule size, and dimensions of extracellular vesicles, when compared to wild-type strains. We detected no difference in growth rates and cell body size. Our results indicate that C. neoformans releases a large suite of proteins during macrophage infection, some of which can modulate fungal virulence and are likely to affect the fungal-macrophage interaction.

Fatal cryptococcal meningitis in a non-HIV patient

Cryptococcal infections (Cryptococcosis) are fatal fungal infections typically caused by Cryptococcus neoformans, a saprophyte frequently found in soil contaminated with  pigeon droppings and frequently seen in immunocompromised (specifically HIV Positive) individuals. Now a day’s awareness is emerging on cryptococcal disease among non-immunocompromised patients also. We present a case of Cryptococcus meningitis (CM) in a patient with cardiopulmonary arrest. A 55 year old male patient came with history of headache and fever with neck rigidity since last 3 months. The patient was admitted as a case of CM based on clinical findings and radiological features. Investigations were done to rule out other disorders of the immune system. He was treated with Amphotericine B (IV) and Fluconazole orally for 2 weeks. Culture of CSF was done which showed presence of Cryptococcus neoformans. It is concluded from the findings that Cryptococcus may also affect non-HIV patients regardless to their immune system.

The performance of rapid on-site evaluation of touch imprints of lung tissue biopsies for the diagnosis of pulmonary cryptococcosis in patients without HIV infection

BACKGROUND AND OBJECTIVE

The diagnosis of pulmonary cryptococcosis depends on serum testing, histopathology and mycological culture; there are few studies on touch imprints of lung tissue biopsies for the diagnosis of pulmonary cryptococcosis in patients without HIV infection. The purpose of the current study was to investigate the accuracy and timeliness of on-site touch imprint cytology in the diagnosis of pulmonary cryptococcosis during CT-guided percutaneous lung biopsy.

METHODS

We retrospectively analyzed the diagnosis and treatment of 56 patients with final proof of pulmonary cryptococcosis through histopathology and culture or surgical resection from September 2015 to February 2021. Diagnostic methods and treatment and the turnaround time for diagnosis were analyzed.

RESULTS

The sensitivity of rapid on-site evaluation was 89.3%, and the sensitivity of serology, histopathology and mycological culture was 53.6%, 91.1%, 61.5%, respectively, compared with the final diagnosis. The average turnaround time to diagnose pulmonary cryptococcosis by on-site touch imprint cytology was 8.3 ± 0.9 min, which was significantly faster than serum testing, histopathology and mycological culture.

CONCLUSION

On-site touch imprint cytology showed good sensitivity and timeliness in the diagnosis of pulmonary cryptococcosis. In addition, it contributed to the triage of biopsies based on the preliminary diagnosis. On-site touch imprint cytology should be applied and promoted in the diagnosis of pulmonary cryptococcosis during biopsy.

It is not always Tuberculosis! A case of pulmonary cryptococcosis in an immunocompetent child in Uganda

Pulmonary cryptococcosis is rare in immunocompetent individuals. Limited data exist regarding its occurrence in children, especially in developing countries. This case report describes an 8-year-old HIV-negative child with pulmonary cryptococcosis, previously diagnosed and treated for tuberculosis twice without improvement. Fine needle aspiration biopsy confirmed the diagnosis of pulmonary cryptococcosis and serum cryptococcal antigen test was positive. The child improved on amphotericin and fluconazole treatment. Despite the limited diagnostic capacity in many resource-constrained settings like Uganda, this case report highlights the need to investigate other causes of pneumonia in immunocompetent children that are not improving on conventional antimicrobial treatments.

Comprehensive Analysis and Risk Identification of Pulmonary Cryptococcosis in Non-HIV Patients

Pulmonary cryptococcosis in the non-human immunodeficiency virus-infected population is uncommon. We aimed to explore the relevance between clinical presentations, radiological findings, and comorbidities and identify the outcome predictors. A total of 321 patients at Taichung Veterans General Hospital between 2005 and 2019 were included; of them, 204 (63.6%) had at least one comorbidity, while 67 (20.9%) had two or more. The most common comorbidities were diabetes mellitus (27.4%), malignant solid tumor (19.6%), autoimmune disease (15.6%), and chronic kidney disease (8.4%). Patients experiencing comorbidity, particularly those with multiple comorbidities, had a higher multilobar and extrapulmonary involvement, which could explain these patients being more symptomatic. In the overall population, extrapulmonary involvement independently predicted disease recurrence and death. Amongst patients with isolated pulmonary cryptococcosis, age, cryptococcal antigen (CrAg) titer in blood, and comorbidities not only predicted the extent of disease, but also its outcome. Of note, patients simultaneously with age ≥ 65 years, CrAg test ≥ 1:128, and multiple comorbidities had the lowest disease control of antifungal treatment (76.9%) and the highest rate of disease recurrence or death from any cause (40.0%). In conclusion, approximately two-thirds of patients had at least one underlying comorbidity. In addition to extrapulmonary involvement, old age, high CrAg titer in blood, and multiple comorbidities could act as risk factors for predicting the extent of disease and outcome.

Update on Pulmonary Cryptococcosis

Pulmonary cryptococcosis is a common but underdiagnosed opportunistic fungal infection in both immunocompromised and immunocompetent patients. The causal agents include at least eight evolutionary distinct haploid lineages as well as their hybrids of the human pathogenic Cryptococcus complex. In this update, we review recent advances in epidemiology, mode of transmission, risk factors, diagnostic methods, and therapy of pulmonary cryptococcosis. Our review suggests significant challenges and opportunities for research, from bedside to benchside and back to bedside.

Examination of a Chinese-made cryptococcal glucuronoxylomannan antigen test in serum and bronchoalveolar lavage fluid for diagnosing pulmonary cryptococcosis in HIV-negative patients

BACKGROUND

We presented the performance of a Chinese-made cryptococcal glucuronoxylomannan (GXM) antigen test using serum and bronchoalveolar lavage fluid (BALF) samples in the HIV-negative Chinese population.

METHODS

Between February 2017 and January 2019, HIV-negative patients with pulmonary cryptococcosis were recruited and followed-up every three months, including completion of a chest CT examination and collection of serum and BALF samples.

RESULTS

Here, thirty-seven confirmed and ten clinically diagnosed patients were recruited. Furthermore, samples from 174 noncryptococcosis patients that may cause false positives were also collected. The sensitivity of a lateral flow assay (LFA) for detecting cryptococcal GXM antigen in serum and BALF samples from confirmed cases was 97% and 95%, respectively, and the specificity was 98.2% and 93%, respectively, and the differences in these values between the BALF and serum samples were not significant. The serum cryptococcal GXM antigen value showed a positive correlation (r: 0.581, p < 0.001) with pulmonary lesion size, while the BALF value showed no correlation (r: 0.253, p: 0.13). The positivity rate of BALF was higher than that of serum when the diameter of the pulmonary lesion was small (diameter less than 20 mm). Moreover, the serum cryptococcal GXM antigen levels showed an overall decreasing trend with the decrease in pulmonary lesion size after antifungal therapy in patient follow-up.

CONCLUSIONS

The Chinese-made cryptococcal GXM antigen test has better sensitivity and specificity for diagnosing pulmonary cryptococcosis in the HIV-negative Chinese population, and it could be used to diagnose and to monitor this disease.

Clinicopathological features of isolated pulmonary cryptococcosis in HIV-negative patients

Objective

To analyse the clinicopathological features of isolated pulmonary cryptococcosis in human immunodeficiency virus (HIV)-negative patients.

Methods

This retrospective study analysed the following data from HIV-negative patients diagnosed with pulmonary cryptococcosis: demographics, underlying diseases, clinical manifestations on admission, laboratory tests, imaging data, results of histopathology, treatment options and outcomes. Sputum samples from all patients were collected and assessed for the presence of yeast or fungi. Cryptococcal antigen testing was performed for some patients. Histopathological analysis was also undertaken for some samples of lung tissue.

Results

The study analysed 37 patients (22 males). Thirteen (35.14%) patients were asymptomatic, 24 (64.86%) were symptomatic and 17 (45.95%) patients had no underlying disease. Out of 25 tested patients, 23 (92.00%) tested positive on the serum cryptococcal capsular polysaccharide antigen test. During 6 to 24 months of follow-up, all 37 patients that were either treated with or without antifungal therapy alone or combined with surgical resection showed complete recovery. One patient made a full recovery without any treatment.

Conclusion

Early identification of pulmonary cryptococcosis in HIV-negative patients and timely detection of cryptococcal antigens in serum or respiratory specimens may help to improve diagnosis, prognosis and treatment of the disease.

Cryptococcus Infection in Captive Callitrichids in the United Kingdom

Cryptococcosis is widely reported in North America and Australia but considered rare in the UK. Disease is mainly caused by Cryptococcus neoformans and Cryptococcus gattii and affects animals and humans. Cases of cryptococcosis have been described in non-human primates, including a few in the Callitrichidae family. Six captive callitrichids from five zoological facilities in the UK were diagnosed with cryptococcosis on post-mortem examination over a 13-year period. Histological examination revealed intralesional yeast bodies consistent with Cryptococcus spp in lung, brain, lymph nodes, larynx, salivary gland and ears. C. neoformans was confirmed in two cases by culture and by culture and polymerase chain reaction (28S rRNA gene), respectively. This case series is the first report of Cryptococcus spp in captive callitrichids in the UK and reinforces the need to include this fungal disease in the differential diagnosis of sick callitrichids in zoo settings.

Pleiotropy and epistasis within and between signaling pathways defines the genetic architecture of fungal virulence

Cryptococcal disease is estimated to affect nearly a quarter of a million people annually. Environmental isolates of Cryptococcus deneoformans, which make up 15 to 30% of clinical infections in temperate climates such as Europe, vary in their pathogenicity, ranging from benign to hyper-virulent. Key traits that contribute to virulence, such as the production of the pigment melanin, an extracellular polysaccharide capsule, and the ability to grow at human body temperature have been identified, yet little is known about the genetic basis of variation in such traits. Here we investigate the genetic basis of melanization, capsule size, thermal tolerance, oxidative stress resistance, and antifungal drug sensitivity using quantitative trait locus (QTL) mapping in progeny derived from a cross between two divergent C. deneoformans strains. Using a "function-valued" QTL analysis framework that exploits both time-series information and growth differences across multiple environments, we identified QTL for each of these virulence traits and drug susceptibility. For three QTL we identified the underlying genes and nucleotide differences that govern variation in virulence traits. One of these genes, RIC8, which encodes a regulator of cAMP-PKA signaling, contributes to variation in four virulence traits: melanization, capsule size, thermal tolerance, and resistance to oxidative stress. Two major effect QTL for amphotericin B resistance map to the genes SSK1 and SSK2, which encode key components of the HOG pathway, a fungal-specific signal transduction network that orchestrates cellular responses to osmotic and other stresses. We also discovered complex epistatic interactions within and between genes in the HOG and cAMP-PKA pathways that regulate antifungal drug resistance and resistance to oxidative stress. Our findings advance the understanding of virulence traits among diverse lineages of Cryptococcus, and highlight the role of genetic variation in key stress-responsive signaling pathways as a major contributor to phenotypic variation.

Landmark clinical observations and immunopathogenesis pathways linked to HIV and Cryptococcus fatal central nervous system co-infection

Cryptococcal meningitis remains one of the leading causes of death among HIV-infected adults in the fourth decade of HIV era in sub-Saharan Africa, contributing to 10%-20% of global HIV-related deaths. Despite widespread use and early induction of ART among HIV-infected adults, incidence of cryptococcosis remains significant in those with advanced HIV disease. Cryptococcus species that causes fatal infection follows systemic spread from initial environmental acquired infection in lungs to antigenaemia and fungaemia in circulation prior to establishment of often fatal disease, cryptococcal meningitis in the CNS. Cryptococcus person-to-person transmission is uncommon, and deaths related to blood infection without CNS involvement are rare. Keen to the persistent high mortality associated with HIV-cryptococcal meningitis, seizures are common among a third of the patients, altered mental status is frequent, anaemia is prevalent with ensuing brain hypoxia and at autopsy, brain fibrosis and infarction are evident. In addition, fungal burden is 3-to-4-fold higher in those with seizures. And high immune activation together with exacerbated inflammation and elevated PD-1/PD-L immune checkpoint expression is immunomodulated phenotypes elevated in CSF relative to blood. Lastly, though multiple Cryptococcus species cause disease in this setting, observations are mostly generalised to cryptococcal infection/meningitis or regional dominant species (C neoformans or gattii complex) that may limit our understanding of interspecies differences in infection, progression, treatment or recovery outcome. Together, these factors and underlying mechanisms are hypotheses generating for research to find targets to prevent infection or adequate therapy to prevent persistent high mortality with current optimal therapy.

Clinical analysis in immunocompetent and immunocompromised patients with pulmonary cryptococcosis in western China

Cryptococcosis is a systemic infection and it may occur in immunocompromised and immunocompetent hosts. In order to better understand the clinical characteristics of patients with PC in different immune status, we retrospectively investigated the clinical, radiological, and treatment profiles of immunocompetent and immunocompromised patients with PC during a 10-year period (2008–2017). As a result, out of 136 patients, 94 (69.1%) were immunocompromised hosts. For the PC patients without CNS involvement, higher percentage of immunocompetent patients (39.5%, 15/38) had asymptomatic presentation than immunocompromised patients (6.3%, 3/48) (P < 0.05). Multiple pulmonary nodules (72.7%, 56/77), ground-glass attenuation/interstitial changes (94.4%, 17/18) and cavitation (88.6%, 31/35) were significantly frequent in immunocompromised patients (P < 0.05). A total of 47 patients were misdiagnosed as tuberculosis or tumors based on CT signs. PC was likely to be misdiagnosed as tuberculosis in immunocompromised patients (88.2%, 15/17), and tumor was more likely to be considered in immunocompetent patients (43.3%, 13/30). Immunocompetent patients accounted for 80% (24/30) of patients with definite diagnosis on surgical lung biopsy. Fluconazole monotherapy can achieve good clinical outcome in most PC patients without central nervous system (CNS) involvement (91.5%, 54/59). After 3 months of treatment, 92.7% (38/41) patients have improved imaging findings. In conclusion, PC has diverse imaging manifestations and it is easily misdiagnosed. Lobectomy should be carefully selected in immunocompetent patients with a single lung lesion. Fluconazole monotherapy is preferred for PC patients without CNS involvement.

Pulmonary cryptococcosis coexisting with central type lung cancer in an immuocompetent patient: a case report and literature review

Background

Pulmonary Cryptococcosis is a common fungal infection mainly caused by Cryptococcus neoformans/C.gattii species in immunocompromised patients. Cases of pulmonary cryptococcosis in patients with normal immune function are increasingly common in China. Clinical and radiographic features of pulmonary cryptococcosis are various and without obvious characteristics, so it is often misdiagnosed as pulmonary metastatic tumor or tuberculosis. When coexisting with malignant lung tumors, it was more difficult to differentiate from metastatic lung cancer, although the coexistence of pulmonary cryptococcosis and central type lung cancer is rare. Reviewing the imaging manifestations and diagnosis of the case and the relevant literature will contribute to recognition of the disease and a decrease in misdiagnoses.

Case presentation

A 72-year-old immunocompetent Han Chinese man had repeated dry cough for more than half a year. CT examination of chest showed an irregular mass at the left hilum of the lung, and two small nodules in the right lung, which were considered as the left central lung cancer with right lung metastasis. However, the patient was diagnosed with pulmonary cryptococcosis coexisting with central type lung cancer based on the results of laboratory examination, percutaneous lung biopsy, fiberoptic bronchoscopy, and surgical pathology. The patient underwent surgical resection of the left central type lung cancer and was placed on fluconazole treatment after a positive diagnosis was made. Five years after the lung cancer surgery, the patient had a recurrence, but the pulmonary cryptococcus nodule disappeared.

Conclusion

Our case shows that CT findings of central type lung cancer with multiple pulmonary nodules are not necessarily metastases, but may be coexisting pulmonary cryptococcosis. CT images of cryptococcosis of the lung were diverse and have no obvious characteristics, so it was very difficult to distinguish from metastatic tumors. CT-guided percutaneous lung biopsy was a simple and efficient method for identification.

Pleural effusion in an immunocompetent host with cryptococcal pneumonia: A case report

BACKGROUND

Pulmonary cryptococcosis is an opportunistic infection that mainly occurs among immunocompromised patients although it can sometimes occur in immunocompetent individuals. However, the imaging findings of pulmonary cryptococcosis in immunocompetent hosts differ from those in immunosuppressed patients. In addition, the most common imaging findings of isolated pulmonary cryptococcosis are single or multiple nodules. Cavities and the halo sign are, however, prevalent in immunosuppressed patients. In immunocompetent patients, lung consolidation, pleural effusion or cavities are scarce.

CASE SUMMARY

A 29-year-old Asian male was admitted to our hospital with complaints of cough and fever that had persisted for a month. As a chest computed tomography scan showed consolidation in his left lower lobe, he was initially diagnosed with pneumonia and received antibiotic treatment. A second review of the chest computed tomography image revealed multiple cavities and pleural effusion. Flexible fiberoptic bronchoscopy was subsequently performed, bronchoalveolar lavage fluid and serum cryptococcal antigen tests were positive. Cryptococcus capsules were observed in bronchoalveolar lavage fluid ink stain. Histopathological examination of a percutaneous lung biopsy from the left lower lobe further revealed granulomatous inflammation, and periodic acid-Schiff staining showed red-colored yeast walls, signifying pulmonary cryptococcosis. The patient was then treated with a daily dose of fluconazole (0.4 g), but the cough and fever still persisted. We therefore changed treatment to voriconazole (0.2 g, twice a day), and the patient’s clinical outcome was satisfactory.

CONCLUSION

Although rare, clinicians should not disregard the possibility of cavities and pleural effusion occurring in immunocompetent hosts without underlying diseases.

Pulmonary Cryptococcosis: comparison of Cryptococcal antigen detection and radiography in Immunocompetent and Immunocompromised patients

Background

We compared the cryptococcal antigen detection and imaging findings between immunocompetent and immunocompromised patients in whom pulmonary cryptococcosis had been diagnosed. The aim of our study was to determine whether the patient’s immune status and radiography affect the detection of cryptococcal antigen.

Methods

According to whether they took immunosuppressive drugs or not, seventy and eight adult patients with pulmonary cryptococcosis were divided into two groups: the immunocompetent group and the immunocompromised group. According to the detection of CrAg, each group was divided into the CrAg+ group and the CrAg- group. Then, clinical records, laboratory examinations and computed tomography findings were collected and analyzed.

Results

No difference was found in baseline characteristics, clinical symptoms, and laboratory investigations. By comparing CrAg detection in these two groups, it was found that the number of CrAg+ cases in the immunocompetent group was more than that in the immunocompromised group. And in the immunocompetent group, diffuse lesions were more common in CrAg+ group and limited lesions were more frequently observed in CrAg- group.

Conclusions

The patient’s immune status and radiography would affect the detection of cryptococcal antigen. And serum CrAg could be a useful tool for the diagnosis of pulmonary cryptococcosis in immunocompetent patients with extensive lung involvement.

Invasive Pulmonary Cryptococcal Infection Masquerading as Lung Cancer with Brain Metastases: A Case Report

Cryptococcosis, a global disease problem, seen frequently in the immuno-suppressed, also affects patients without apparent immuno-suppression. Pulmonary cryptococcosis patients often present as cryptococcal pneumonia, whereas intracranial cryptococcosis presents with meningitis. We present a 33-year-old immunocompetent man, diagnosed with invasive pulmonary cryptococcal disease with spread to the brain. This case is unique because the patient was previously treated for tuberculosis and presented with typical bronchopulmonary thoracic, extra-thoracic as well as computed tomography (CT) scan features suggestive of lung cancer. Cryptococcosis was diagnosed by identification of oval thick-walled yeast on histology of lung biopsy specimen. The patient was treated with flucytosine and fluconazole initially and subsequently with Amphotericin B and fluconazole. He made clinical improvement with the resolution of symptoms but had residual radiological features. Invasive cryptococcosis affecting the lung and brain may present with a clinical picture similar to metastatic lung cancer. We recommend routine fungal stains and fungal culture in suspected cases.

Pulmonary cryptococcosis: A review of pathobiology and clinical aspects

Pulmonary cryptococcosis is an important opportunistic invasive mycosis in immunocompromised patients, but it is also increasingly seen in immunocompetent patients. The main human pathogens are Cryptococcus neoformans and C. gattii, which have a worldwide distribution. In contrast to cryptococcal meningitis, pulmonary cryptococcosis is still underdiagnosed because of limitations in diagnostic tools. It can mimic lung cancer, pulmonary tuberculosis, bacterial pneumonia, and other pulmonary mycoses both clinically and radiologically. Pulmonary nodules are the most common radiological feature, but these are not specific to pulmonary cryptococcosis. The sensitivity of culture of respiratory samples for Cryptococcus is poor and a positive result may also reflect colonisation. Cryptococcal antigen (CrAg) with lateral flow device is a fast and sensitive test and widely used on serum and cerebrospinal fluid, but sera from patients with pulmonary cryptococcosis are rarely positive in the absence of disseminated disease. Detection of CrAg from respiratory specimens might assist the diagnosis of pulmonary cryptococcosis but there are very few data. Molecular detection techniques such as multiplex reverse transcription polymerase chain reaction (RT-PCR) could also provide better sensitivity but these still require validation for respiratory specimens. The first line of treatment for pulmonary cryptococcosis is fluconazole, or amphotericin B and flucytosine for those with central nervous system involvement. Pulmonary cryptococcosis worsens the prognosis of cryptococcal meningitis. In this review, we summarize the biological aspects of Cryptococcus and provide an update on the diagnosis and management of pulmonary cryptococcosis.

Incidental Cryptococcal lung mass in an immunocompetent patient

Cryptococcus is an encapsulated fungal organism often implicated in central nervous system and pulmonary disease in patients with AIDS or other immunocompromising diseases. However, immunocompetent hosts can also be infected. In these cases, symptoms are generally mild and common radiographic findings include small, well-defined, smoothly marginated pulmonary nodules. We present a case of a 31-year-old man without any immunocompromising factors found to have pulmonary Cryptococcal infection presenting as a large lung mass.

The use of surgery in a real-world clinic to diagnose and treat pulmonary cryptococcosis in immunocompetent patients

Background

We evaluated the role played by surgery in the diagnosis and treatment of pulmonary cryptococcosis (PC) in immunocompetent subjects.

Methods

We retrospectively studied 53 immunocompetent patients who were pathologically diagnosed with PC between January 2000 and December 2016 in a tertiary referral center. We compared the radiological presentations of, and diagnostic modalities used to evaluate, patients diagnosed both surgically and non-surgically. We also compared the treatment outcomes of patients who underwent surgical resection alone and those who received additional antifungals following surgical resection.

Results

Of the 53 patients, 30 (57%) were diagnosed via non-surgical modalities including percutaneous needle biopsy (PCNB) (n=29) and transbronchial lung biopsy (TBLB) (n=1); and 23 (43%) were diagnosed by surgical modalities including video-assisted thoracoscopic wedge resection (n=22) and lobectomy (n=1). An initial clinical suspicion of a lung malignancy was associated with the use of surgical diagnostic approaches (P<0.001). Whereas undetermined locations were associated with the use of surgical diagnostic approaches, radiological findings such as clustered nodular patterns (P<0.001), cavities (P=0.005), air bronchograms (P<0.001), and peripheral lesions (P<0.001) were associated with the use of non-surgical diagnostic approaches. Of the 30 non-surgically diagnosed patients, 21 (70%) were treated with antifungals and 9 (30%) were followed-up without treatment. Of the 23 patients who underwent surgical treatment, 8 received additional antifungals. The proportion of patients who had radiological improvement was significantly higher in surgically diagnosed patients than non-surgically diagnosed patients (100% vs. 73%; P=0.007). However, there was no significant difference in disease progression between patients who underwent surgical resection alone and those who additionally received antifungals (P=0.999).

Conclusions

Surgical resection was required in some patients to diagnose PC. An initial suspicion of a lung malignancy was associated with use of surgical diagnostic approaches. Surgical resection not only afforded reliable diagnoses but also effectively treated PC. There was no need for additional antifungals after complete surgical resection.

The performance of serum cryptococcal capsular polysaccharide antigen test, histopathology and culture of the lung tissue for diagnosis of pulmonary cryptococcosis in patients without HIV infection

Background

Clinicians may fail to make an early diagnosis of pulmonary cryptococcosis (PC) without HIV infection. Serum cryptococcal capsular polysaccharide antigen (CrAg) test, histopathology and culture of lung tissue play different roles in diagnosis of PC.

Objective

To investigate the performance of serum CrAg test, histopathology and culture of the lung tissue in diagnosis of PC without HIV infection.

Patients/methods

From January 2011 to September 2017, patients with proven PC were recruited from a teaching hospital in southern China. Those patients with HIV infection, PC confirmed by surgery or PC with probable or possible diagnosis were excluded from the study. Latex agglutination test and CrAg lateral flow assay were used for detection of serum CrAg. Lung biopsy and needle aspiration were performed under computed tomography guidance.

Results

Eighty-nine patients with proven PC including 41 male (46.1%) and 48 female (53.9%) were enrolled. Fifty-one (57.3%) patients had underlying disease. Positive CrAg test was found in 83 (93.3%) cases. Among six cases with negative CrAg test, PC was confirmed by histology in two cases and positive culture in four cases. The histopathological results of 77 (86.5%) cases revealed cryptococcal granuloma and 12 cases showed chronic inflammation, which was confirmed by positive culture. Among 65 cases, the diseased tissue of 46 (70.8%) cases presented Cryptococcus neoformans in the culture and one case was diagnosed with lung cancer coexisting with PC.

Conclusion

Our findings showed that serum CrAg test is rapid and sensitive in diagnosing PC, histology is important for confirming PC and culture plays a complementary role. Biopsied lung tissue should be submitted for cultures whenever feasible.

Pulmonary cryptococcosis coexisting with adenocarcinoma: a case report and review of the literature

Background

Pulmonary cryptococcosis is a common fungal infection frequently seen in immunocompromised patients. Owing to its nonspecific clinical and radiographic features, the differential diagnosis with secondary tuberculosis, malignant tumor, and bacterial pneumonia is sometimes difficult. Many case reports have focused on misdiagnosis of pulmonary cryptococcosis as a malignant tumor. But to the best of our knowledge, the coexistence of pulmonary cryptococcosis and malignant tumor is rarely presented.

Case presentation

A 52-year-old immunocompetent Han Chinese woman was presented to our emergency department complaining of headache and vomiting accompanied by postural changes. She was diagnosed with pulmonary cryptococcosis according to results of laboratory tests, computed tomography, and percutaneous lung biopsy. Owing to the poor therapeutic effects of 6-month fluconazole treatment, she underwent a second percutaneous lung biopsy and was diagnosed with pulmonary cryptococcosis coexisting with adenocarcinoma. Delayed treatment of malignant tumor resulted in lymph node metastasis, higher pathologic stage, and probably poorer prognosis.

Conclusions

Our patient’s case serves as a reminder not to misdiagnose pulmonary cryptococcosis coexisting with adenocarcinoma.

Efficacy of Prosopilosidine from Prosopis glandulosa var. glandulosa against Cryptococcus neoformans Infection in a Murine Model

In this study, 2,3-dihydro-1H-indolizinium alkaloid-prosopilosidine (PPD), that was isolated from Prosopis glandulosa, was evaluated against C. neoformans in a murine model of cryptococcosis. In vitro and in vivo toxicity of indolizidines were also evaluated. Mice were infected via the tail vein with live C. neoformans. Twenty-four hours post-infection, the mice were treated with PPD once a day (i.p.) or twice a day (bid) orally, or with amphotericin B (Amp B) intraperitoneally (IP), or with fluconazole (Flu) orally for 5 days. The brains of all of the animals were aseptically removed and the numbers of live C. neoformans were recovered. In vitro toxicity of indolizidine alkaloids was determined in HepG2 cells. PPD showed to be potent in vivo activity against C. neoformans at a dose of 0.0625 mg/kg by eliminating ~76% of the organisms compared to ~83% with Amp B (1.5 mg/kg). In addition, PPD was found to be equally efficacious, but less toxic, at either 0.125 or 0.0625 mg/kg compared to Amp B (1.5 mg/kg) when it was administered bid (twice a day) by an i.p. route. When tested by an oral route, PPD (10 mg/kg) showed potent activity in this murine model of cryptococcosis with ~82% of organisms eliminated from the brain tissue, whereas Flu (15 mg/kg) reduced ~90% of the infection. In vitro results suggest that quaternary indolizidines were less toxic as compared to those of tertiary bases. PPD (20 mg/kg) did not cause any alteration in the plasma chemistry profiles. These results indicated that PPD was active in eliminating cryptococcal infection by oral and i.p. routes at lower doses compared to Amp B. or Flu.

Pulmonary cryptococcosis in immunocompetent patient: a case report

Pulmonary cryptococcosis (PC) is an opportunistic and conditional disease. It commonly occurs in immunocompromised patients. We presented a case of PC in an immunocompetent patient. This patient had the complaints of irritating cough and shortness of breath. A variety of antibiotic treatment was ineffective. The patient eventually received percutaneous transcutaneous biopsy and PC was diagnosed. Patient was treated by intravenous fluconazole for two weeks. The patient's follow-up was performed by Pulmonary Department, and we learned that the patient was well.