Pulmonary cryptococcosis: A review of pathobiology and clinical aspects

Extensive Pulmonary Cryptococcosis as a Presentation in an Immunocompetent Young Male: A Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Finding

A 42-year-old male presented with a dry cough, breathlessness, and fever. He underwent a computed tomography that revealed large consolidation in the right lung. Biopsy revealed Cryptococcus neoformans. He was on antifungal for 4 months with no clinicoradiological improvement. 18F- fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) showed consolidations in the right lung with multiple lung nodules. 18F-FDG PET/CT ascertains the diagnosis of residual fungal infection and rules out extrapulmonary involvement.

CD146 deficiency promotes inflammatory type 2 responses in pulmonary cryptococcosis

Cryptococcus neoformans (C. neoformans) is an important opportunistic fungal pathogen for pulmonary cryptococcosis. Previously, we demonstrated that CD146 mediated the adhesion of C. neoformans to the airway epithelium. CD146 is more than an adhesion molecule. In the present study, we aimed to explore the roles of CD146 in the inflammatory response in pulmonary cryptococcosis. CD146 was decreased in lung tissues from patients with pulmonary cryptococcosis. Similarly, C. neoformans reduced pulmonary CD146 expression in mice following intratracheal inoculation. To explore the pathological roles of CD146 reduction in pulmonary cryptococcosis, CD146 knockout (KO) mice were inoculated with C. neoformans via intratracheal instillation. CD146 deficiency aggravated C. neoformans infection, as evidenced by a shortened survival time and increased fungal burdens in the lung. Inflammatory type 2 cytokines (IL-4, IL-5, and TNF-α) and alternatively activated macrophages were increased in the pulmonary tissues of CD146 KO-infected mice. CD146 is expressed in immune cells (macrophages, etc.) and nonimmune cells, i.e., epithelial cells and endothelial cells. Bone marrow chimeric mice were established and infected with C. neoformans. CD146 deficiency in immune cells but not in nonimmune cells increased fungal burdens in the lung. Mechanistically, upon C. neoformans challenge, CD146 KO macrophages produced more neutrophil chemokine KC and inflammatory cytokine TNF-α. Meanwhile, CD146 KO macrophages decreased the fungicidity and production of reactive oxygen species. Collectively, C. neoformans infection decreased CD146 in pulmonary tissues, leading to inflammatory type 2 responses, while CD146 deficiency worsened pulmonary cryptococcosis.

Screening and Synthesis of Tetrazole Derivatives that Inhibit the Growth of Cryptococcus Species

Cryptococcosis has become a major health problem worldwide and caused morbidity and mortality in immunocompromised patients, especially those infected with human immunodeficiency virus (HIV). Despite the global distribution of cryptococcosis, the number and types of the available antifungals are limited, and the treatment outcomes in HIV patients are generally poor. In this study, we screened a compound library and identified one tetrazole derivative as an efficient inhibitor of Cryptococcus neoformans and Cryptococcus gattii. We further designed and synthesized a series of tetrazole derivatives and determined their structure-activity relationship, demonstrating that tetrazole backbone-containing compounds could be developed as novel antifungal drugs with distinct mechanisms against Cryptococcus spp. Our findings provide a starting point for novel target identification and structural optimization to develop a distinct class of therapeutics for patients with cryptococcosis.

The SSS revolution in fungal diagnostics: speed, simplicity and sensitivity

INTRODUCTION

Fungal disease has historically presented a diagnostic challenge due to its often non-specific clinical presentations, relative infrequency and reliance on insensitive and time-intensive fungal culture.

SOURCES OF DATA

We present the recent developments in fungal diagnostics in the fields of serological and molecular diagnosis for the most clinically relevant pathogens; developments that have the potential to revolutionize fungal diagnosis through improvements in speed, simplicity and sensitivity. We have drawn on a body of evidence including recent studies and reviews demonstrating the effectiveness of antigen and antibody detection and polymerase chain reaction (PCR) in patients with and without concurrent human immunodeficiency virus infection.

AREAS OF AGREEMENT

This includes recently developed fungal lateral flow assays, which have a low cost and operator skill requirement that give them great applicability to low-resource settings. Antigen detection for Cryptococcus, Histoplasma and Aspergillus spp. are much more sensitive than culture. PCR for Candida spp., Aspergillus spp., Mucorales and Pneumocystis jirovecii is more sensitive than culture and usually faster.

AREAS OF CONTROVERSY

Effort must be made to utilize recent developments in fungal diagnostics in clinical settings outside of specialist centres and integrate their use into standard medical practice. Given the clinical similarities of the conditions and frequent co-infection, further study is required into the use of serological and molecular fungal tests, particularly in patients being treated for tuberculosis.

GROWING POINTS

Further study is needed to clarify the utility of these tests in low-resource settings confounded by a high prevalence of tuberculosis.

AREAS TIMELY FOR DEVELOPING RESEARCH

The diagnostic utility of these tests may require revision of laboratory work flows, care pathways and clinical and lab coordination, especially for any facility caring for the immunosuppressed, critically ill or those with chronic chest conditions, in whom fungal disease is common and underappreciated.

Predictive Performance of Scoring Systems for Mortality Risk in Patients with Cryptococcemia: An Observational Study

Cryptococcal infection is usually diagnosed in immunocompromised individuals and those with meningeal involvement, accounting for most cryptococcosis. Cryptococcemia indicates a poor prognosis and prolongs the course of treatment. We use the scoring systems to predict the mortality risk of cryptococcal fungemia. This was a single hospital-based retrospective study on patients diagnosed with cryptococcal fungemia confirmed by at least one blood culture collected from the emergency department covering January 2012 and December 2020 from electronic medical records in the Taichung Veterans General Hospital. We enrolled 42 patients, including 28 (66.7%) males and 14 (33.3%) females with a mean age of 63.0 ± 19.7 years. The hospital stay ranged from 1 to 170 days (a mean stay of 44.4 days), and the overall mortality rate was 64.3% (27/42). In univariate analysis, the AUC of ROC for MEWS, RAPS, qSOFA, MEWS plus GCS, REMS, NEWS, and MEDS showed 0.833, 0.842, 0.848, 0.846, 0.846, 0.878, and 0.905. In the multivariate Cox regression analysis, all scoring systems, older age, lactate, MAP, and DBP, indicated significant differences between survivor and non-survivor groups. Our results show that all scoring systems could apply in predicting the outcome of patients with cryptococcal fungemia, and the MEDS displays the best performance. We recommend a further large-scale prospective study for patients with cryptococcal fungemia.

Ethanolic Extract Propolis-Loaded Niosomes Diminish Phospholipase B1, Biofilm Formation, and Intracellular Replication of Cryptococcus neoformans in Macrophages

Secretory phospholipase B1 (PLB1) and biofilms act as microbial virulence factors and play an important role in pulmonary cryptococcosis. This study aims to formulate the ethanolic extract of propolis-loaded niosomes (Nio-EEP) and evaluate the biological activities occurring during PLB1 production and biofilm formation of Cryptococcus neoformans. Some physicochemical characterizations of niosomes include a mean diameter of 270 nm in a spherical shape, a zeta-potential of -10.54 ± 1.37 mV, and 88.13 ± 0.01% entrapment efficiency. Nio-EEP can release EEP in a sustained manner and retains consistent physicochemical properties for a month. Nio-EEP has the capability to permeate the cellular membranes of C. neoformans, causing a significant decrease in the mRNA expression level of PLB1. Interestingly, biofilm formation, biofilm thickness, and the expression level of biofilm-related genes (UGD1 and UXS1) were also significantly reduced. Pre-treating with Nio-EEP prior to yeast infection reduced the intracellular replication of C. neoformans in alveolar macrophages by 47%. In conclusion, Nio-EEP mediates as an anti-virulence agent to inhibit PLB1 and biofilm production for preventing fungal colonization on lung epithelial cells and also decreases the intracellular replication of phagocytosed cryptococci. This nano-based EEP delivery might be a potential therapeutic strategy in the prophylaxis and treatment of pulmonary cryptococcosis in the future.

Simultaneous and Visual Detection of KPC and NDM Carbapenemase-Encoding Genes Using Asymmetric PCR and Multiplex Lateral Flow Strip

Carbapenem-resistant Enterobacteriaceae (CRE) infections constitute a threat to public health, and KPC and NDM are the major carbapenemases of concern. Rapid diagnostic tests are highly desirable in point-of-care (POC) and emergency laboratories with limited resources. Here, we developed a multiplex lateral flow assay based on asymmetric PCR and barcode capture probes for the simultaneous detection of KPC-2 and NDM-1. Biotinylated barcode capture probes corresponding to the KPC-2 and NDM-1 genes were designed and cast onto two different sensing zones of a nitrocellulose membrane after reacting with streptavidin to prepare a multiplex lateral flow strip. Streptavidin-coated gold nanoparticles (SA-AuNPs) were used as signal reporters. In response to the target carbapenemase genes, biotin-labelled ssDNA libraries were produced by asymmetric PCR, which bond to SA-AuNPs via biotin and hybridise with the barcode capture probe via a complementary sequence, thereby bridging SA-AuNPs and the barcode capture probe to form visible red lines on the detection zones. The signal intensities were proportional to the number of resistance genes tested. The strip sensor showed detection limits of 0.03 pM for the KPC-2 and 0.07 pM for NDM-1 genes, respectively, and could accurately distinguish between KPC-2 and NDM-1 genes in CRE strains. For the genotyping of clinical isolates, our strip exhibited excellent consistency with real-time fluorescent quantitative PCR and gene sequencing. Given its simplicity, cost-effectiveness, and rapid analysis accomplished by the naked eye, the multiplex strip is promising auxiliary diagnostic tool for KPC-2 and NDM-1 producers in routine clinical laboratories.

Opportunistic Fungal Invasion in COVID-19 Pandemic: A Critical Review in Diagnosis and Management

Severe acute respiratory syndrome corona virus-2 (SARS-CoV-2) is the culprit behind the pandemic across the globe in recent decades. Variants of SARS-CoV especially coronavirus disease 2019 (COVID-19)-related fungus might not be identified or might be misdiagnosed on a worldwide scale. Patients of COVID-19 acquired invasive mycoses, especially if they are very ill or immunosuppressed. Clinical intervention based on various standard guidelines would be necessary to guarantee that Aspergillus and Candida -infected COVID-19 patients are adequately treated. To facilitate clinical professionals, doctors, paramedics, and laboratory staff in the treatment of various variants of COVID-19 patients with concurrent aspergillosis, candidiasis, mucormycosis, or cryptococcosis, a tabulation format is drafted in this study. We believe it is prudent to take into account the general nature, and variety of the mycosis that is arriving, the strength and limits of the diagnostic tools, clinical conditions, and the need for standardized or customized therapy in various coronavirus-infected patients.

Catestatin: Antimicrobial Functions and Potential Therapeutics

The rapid increase in drug-resistant and multidrug-resistant infections poses a serious challenge to antimicrobial therapies, and has created a global health crisis. Since antimicrobial peptides (AMPs) have escaped bacterial resistance throughout evolution, AMPs are a category of potential alternatives for antibiotic-resistant "superbugs". The Chromogranin A (CgA)-derived peptide Catestatin (CST: hCgA352-372; bCgA344-364) was initially identified in 1997 as an acute nicotinic-cholinergic antagonist. Subsequently, CST was established as a pleiotropic hormone. In 2005, it was reported that N-terminal 15 amino acids of bovine CST (bCST1-15 aka cateslytin) exert antibacterial, antifungal, and antiyeast effects without showing any hemolytic effects. In 2017, D-bCST1-15 (where L-amino acids were changed to D-amino acids) was shown to exert very effective antimicrobial effects against various bacterial strains. Beyond antimicrobial effects, D-bCST1-15 potentiated (additive/synergistic) antibacterial effects of cefotaxime, amoxicillin, and methicillin. Furthermore, D-bCST1-15 neither triggered bacterial resistance nor elicited cytokine release. The present review will highlight the antimicrobial effects of CST, bCST1-15 (aka cateslytin), D-bCST1-15, and human variants of CST (Gly364Ser-CST and Pro370Leu-CST); evolutionary conservation of CST in mammals; and their potential as a therapy for antibiotic-resistant "superbugs".

False positive detection of serum cryptococcal antigens due to insufficient sample dilution: A case series

At present, with the development of technology, the detection of cryptococcal antigen (CRAG) plays an increasingly important role in the diagnosis of cryptococcosis. However, the three major CRAG detection technologies, latex agglutination test (LA), lateral flow assay (LFA) and Enzyme-linked Immunosorbent Assay, have certain limitations. Although these techniques do not often lead to false-positive results, once this result occurs in a particular group of patients (such as human immunodeficiency virus patients), it might lead to severe consequences.

Approach to the diagnosis of invasive fungal infections of the respiratory tract in the immunocompromised host

PURPOSE OF REVIEW

The burden of invasive fungal infection is increasing worldwide, largely due to a growing population at-risk. Most serious human fungal pathogens enter the host via the respiratory tract. Early identification and treatment of invasive fungal respiratory infections (IFRIs) in the immunocompromised host saves lives. However, their accurate diagnosis is a difficult challenge for clinicians and mortality remains high.

RECENT FINDINGS

This article reviews IFRIs, focussing on host susceptibility factors, clinical presentation, and mycological diagnosis. Several new diagnostic tools are coming of age including molecular diagnostics and point-of-care antigen tests. As diagnosis of IFRI relies heavily on invasive procedures like bronchoalveolar lavage and lung biopsy, several novel noninvasive diagnostic techniques are in development, such as metagenomics, 'volatilomics' and advanced imaging technologies.

SUMMARY

Where IFRI cannot be proven, clinicians must employ a 'weights-of-evidence' approach to evaluate host factors, clinical and mycological data. Implementation studies are needed to understand how new diagnostic tools can be best applied within clinical pathways. Differentiating invasive infection from colonization and identifying antifungal resistance remain key challenges. As our diagnostic arsenal expands, centralized clinical mycology laboratories and efforts to ensure access to new diagnostics in low-resource settings will become increasingly important.

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.

Clinical and imaging characteristics of pulmonary cryptococcosis: a comparative analysis of 118 non-AIDS patients in China

The accurate diagnosis of pulmonary cryptococcosis (PC) is an important guarantee for the selection of reasonable treatment methods. In this paper, the clinical and imaging manifestations of PC in non-AIDS patients were retrospectively analyzed, and according to whether there was an underlying disease, a comparative analysis was carried out to deepen the understanding of PC, and improve the accuracy of its diagnosis. Both clinical and CT imaging data of 118 PC patients were analyzed retrospectively. The clinical manifestations of PC patients were not specific, and 61 patients had no apparent symptoms. A total of 49 patients (49/118) were treated with antifungal agents alone, 46 of them had follow-up records after treatment, and 91.3% (42/46) of them achieved a good outcome. The most common imaging sign was the subpleural nodule or mass. Other main imaging signs include bronchial air sign (50/118), halo sign (32/118), ring target sign (65/118), lobulation sign (72/118), and necrosis (76/118). In terms of age, halo sign, and ring target sign, there were significant differences between the group with underlying disease and the group without underlying disease (P < .05). The CT manifestations of PC have some characteristics, and using antifungal agents can achieve good outcomes.

Pulmonary Cryptococcosis and Pulmonary Fibrosis: A Complication of COVID-19 Pneumonia

Acute respiratory distress syndrome (ARDS) and pulmonary fibrosis (PF) are increasingly identified as complications of coronavirus disease 2019 (COVID-19) infection, the latter being managed with tapering dose glucocorticoids. Studies have shown improved outcomes with steroid use in this subset of patients; however, the use of high doses of steroids predisposes these patients to develop various complications such as opportunistic infections. The incidence of pulmonary cryptococcosis (PC) in patients with post-COVID-19 PF is not known. Here, we discuss a middle-aged male, with no pulmonary comorbidities, who developed PC secondary to the immunocompromised state from high-dose steroid use for the management of post-COVID-19 PF.

Pulmonary Cryptococcosis Diagnosed by a Transbronchial Lung Cryobiopsy in a Patient with Rheumatoid Arthritis

A 77-year-old woman with seronegative rheumatoid arthritis who was being treated with prednisolone (8 mg/day) and methotrexate (12 mg/week) visited our hospital with an 11-day history of a fever and dyspnea. Chest computed tomography showed infiltration in the right lower lobe. A transbronchial lung cryobiopsy (TBLC) showed cryptococcal cells, and bronchoalveolar lavage fluid later showed growth of Cryptococcus neoformans. She was treated with amphotericin B and flucytosine for about four weeks, and the pulmonary shadows improved. The treatment was then changed to fluconazole as outpatient consolidation and maintenance therapy. A rare case of pulmonary cryptococcosis diagnosed by a TBLC is reported.

Infectious and Inflammatory Pathways to Cough

Coughing is a dynamic physiological process resulting from input of vagal sensory neurons innervating the airways and perceived airway irritation. Although cough serves to protect and clear the airways, it can also be exploited by respiratory pathogens to facilitate disease transmission. Microbial components or infection-induced inflammatory mediators can directly interact with sensory nerve receptors to induce a cough response. Analysis of cough-generated aerosols and transmission studies have further demonstrated how infectious disease is spread through coughing. This review summarizes the neurophysiology of cough, cough induction by respiratory pathogens and inflammation, and cough-mediated disease transmission.

Opportunistic infections associated with Janus kinase inhibitor treatment for rheumatoid arthritis: A structured literature review

BACKGROUND

The availability of Janus kinase (JAK) inhibitors has transformed the management of rheumatoid arthritis (RA), helping patients achieve clinical remission. However, the emergence of opportunistic infections (OIs) associated with the use of JAK inhibitors has been reported. This structured literature review was conducted to summarize reports of OIs associated with JAK inhibitor treatment for RA in clinical trials.

METHODS

Structured searches were performed in MEDLINE® and Embase® to identify relevant clinical trial data through March 2021. Bibliographic searches of recent reviews were also conducted, and gray literature searches were used to supplement key gap areas. Publications were screened, extracted, and quality assessed. Data were narratively synthesized.

RESULTS

Following screening, 105 publications describing 62 unique clinical trials reporting the rates of OIs in RA patients treated with JAK inhibitors were included. Overall, the highest exposure-adjusted incidence rate was reported for herpes zoster (HZ) infection (any form), followed by OI (any) and tuberculosis based on limited data from clinical trials with approved doses of JAK inhibitors. Lack of head-to-head trials and differences in trial design preclude direct comparison across JAK inhibitors. Higher rates of OIs were noted in the Asian and Australian populations compared with the global population. Higher rates of OIs were also noted with increasing dose of JAK inhibitors in most clinical trial data.

CONCLUSIONS

HZ was the most common OI reported among RA patients using all currently approved JAK inhibitors in clinical trials, although tuberculosis and other OIs were also reported. More long-term safety studies in the real-world setting are needed to compare the risk of OIs between various JAK inhibitors.

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.

An Alternative Diagnostic Method for C. neoformans: Preliminary Results of Deep-Learning Based Detection Model

Cryptococcus neoformans is an opportunistic fungal pathogen with significant medical importance, especially in immunosuppressed patients. It is the causative agent of cryptococcosis. An estimated 220,000 annual cases of cryptococcal meningitis (CM) occur among people with HIV/AIDS globally, resulting in nearly 181,000 deaths. The gold standards for the diagnosis are either direct microscopic identification or fungal cultures. However, these diagnostic methods need special types of equipment and clinical expertise, and relatively low sensitivities have also been reported. This study aims to produce and implement a deep-learning approach to detect C. neoformans in patient samples. Therefore, we adopted the state-of-the-art VGG16 model, which determines the output information from a single image. Images that contain C. neoformans are designated positive, while others are designated negative throughout this section. Model training, validation, testing, and evaluation were conducted using frameworks and libraries. The state-of-the-art VGG16 model produced an accuracy and loss of 86.88% and 0.36203, respectively. Results prove that the deep learning framework VGG16 can be helpful as an alternative diagnostic method for the rapid and accurate identification of the C. neoformans, leading to early diagnosis and subsequent treatment. Further studies should include more and higher quality images to eliminate the limitations of the adopted deep learning model.

Human Airway Epithelium Responses to Invasive Fungal Infections: A Critical Partner in Innate Immunity

The lung epithelial lining serves as the primary barrier to inhaled environmental toxins, allergens, and invading pathogens. Pulmonary fungal infections are devastating and carry high mortality rates, particularly in those with compromised immune systems. While opportunistic fungi infect primarily immunocompromised individuals, endemic fungi cause disease in immune competent and compromised individuals. Unfortunately, in the case of inhaled fungal pathogens, the airway epithelial host response is vastly understudied. Furthering our lack of understanding, very few studies utilize primary human models displaying pseudostratified layers of various epithelial cell types at air-liquid interface. In this review, we focus on the diversity of the human airway epithelium and discuss the advantages and disadvantages of oncological cell lines, immortalized epithelial cells, and primary epithelial cell models. Additionally, the responses by human respiratory epithelial cells to invading fungal pathogens will be explored. Future investigations leveraging current human in vitro model systems will enable identification of the critical pathways that will inform the development of novel vaccines and therapeutics for pulmonary fungal infections.

Could the Lung Be a Gateway for Amphotericin B to Attack the Army of Fungi?

Fungal diseases are a significant cause of morbidity and mortality worldwide, primarily affecting immunocompromised patients. Aspergillus, Pneumocystis, and Cryptococcus are opportunistic fungi and may cause severe lung disease. They can develop mechanisms to evade the host immune system and colonize or cause lung disease. Current fungal infection treatments constitute a few classes of antifungal drugs with significant fungi resistance development. Amphotericin B (AmB) has a broad-spectrum antifungal effect with a low incidence of resistance. However, AmB is a highly lipophilic antifungal with low solubility and permeability and is unstable in light, heat, and oxygen. Due to the difficulty of achieving adequate concentrations of AmB in the lung by intravenous administration and seeking to minimize adverse effects, nebulized AmB has been used. The pulmonary pathway has advantages such as its rapid onset of action, low metabolic activity at the site of action, ability to avoid first-pass hepatic metabolism, lower risk of adverse effects, and thin thickness of the alveolar epithelium. This paper presented different strategies for pulmonary AmB delivery, detailing the potential of nanoformulation and hoping to foster research in the field. Our finds indicate that despite an optimistic scenario for the pulmonary formulation of AmB based on the encouraging results discussed here, there is still no product registration on the FDA nor any clinical trial undergoing ClinicalTrial.gov.

A 52-Year-Old Obese Man With Persistent Cough

CASE PRESENTATION

A 52-year-old man was referred to our hospital with an abnormal chest radiography infiltrate. He presented with cough that persisted for 1 month without fever, chills, dyspnea, or sputum. He has been treated with clarithromycin 400 mg/d for 1 week with no improvement. He had a history of hypertension, hyperuricemia, and gastroesophageal reflux disease. He had no family history of respiratory disease. He smoked 10 cigarettes daily for 10 years, which he had quit 15 years ago. He denied a history of alcohol or illicit drug use, occupational exposure, recent travel, and exposure to TB. He reported being sexually active with one current partner.

Comparison of the clinical manifestations and chest CT findings of pulmonary cryptococcosis in immunocompetent and immunocompromised patients: a systematic review and meta-analysis

Objective

The purpose of our study was to perform a meta-analysis and systematic review to compare differences in clinical manifestations and chest computed tomography (CT) findings between immunocompetent and immunocompromised pulmonary cryptococcosis (PC) patients.

Methods

An extensive search for relevant studies was performed using the PubMed, EMBASE, Cochrane Library, and Web of Sciences databases from inception to September 30, 2021. We included studies that compared the clinical manifestations and chest CT findings between immunocompetent and immunocompromised PC patients. Study bias and quality assessment were performed using the Newcastle–Ottawa Scale (NOS).

Results

Nine studies involving 248 immunocompromised and 276 immunocompetent PC patients were included in our analysis. The NOS score of each eligible study was above 5, indicating moderate bias. The proportion of elderly patients (> = 60 years old) in the immunosuppressed group was significantly higher than that in the immunocompetent group (OR = 2.90, 95% CI (1.31–6.43), Z = 2.63, p = 0.01). Fever (OR = 7.10, 95% CI (3.84–13.12), Z = 6.25, p < 0.000) and headache (OR = 6.92, 95% CI (2.95–16.26), Z = 4.44, p < 0.000) were more common in immunosuppressed patients. According to thin-section CT findings, lesions were more frequently distributed in the upper lobe (OR = 1.90, 95% CI (1.07–3.37), Z = 2.2, p = 0.028) in immunocompromised individuals. The proportions of patients with cavity sign (OR = 5.11, 95% CI (2.96–8.83), Z = 5.86, p = 0.00), ground-glass attenuation (OR = 5.27, 95% CI (1.60–17.35), Z = 2.73, p = 0.01), and mediastinal lymph node enlargement (OR = 2.41, 95% CI (1.12–5.20), Z = 2.24, p = 0.03) were significantly higher in immunocompromised patients.

Conclusion

No significant differences in nonspecific respiratory symptoms were found between immunocompromised and immunocompetent PC patients. Nevertheless, fever and headache were more common in immunocompromised patients. Among the CT findings, cavity, ground-glass attenuation, and mediastinal lymph node enlargement were more common in immunocompromised individuals.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-02175-9.

Metagenomic next-generation sequencing assists in the diagnosis of Cryptococcus pneumonia: Case series and literature review

Background

Pulmonary cryptococcosis (PC) was once thought to occur only in patients with immune deficiencies, such as tested positive for the Human Immunodeficiency Virus (HIV). However, in recent years, it has been discovered that more than half of the patients with PC in our nation are individuals with normal immune function. As more and more PC cases are recorded, our diagnosis and treatment approaches, as well as our understanding of PC, are gradually improving. In reality, most PC patients still have a high incidence of misdiagnosis on their initial visit. It is primarily linked to the diverse clinical manifestations, atypical imaging findings, and inaccurate diagnostic approaches.

Methods

The research was conducted from 2019 to 2020. We performed traditional microbiological testing and mNGS on sample from patients with fever of Pulmonary nodules or lung infections. Furthermore, we collected patients' baseline information, clinical features, laboratory and imaging examination results, diagnosis, treatment and outcome. In the end, we confirmed three cases of PC using biopsy and mNGS.

Conclusion

Our data demonstrates that mNGS can be utilized as an auxiliary method for PC diagnosis. Early mNGS aids in the identification of pathogens, enabling early diagnosis and treatment, as well as a reduction in the rate of misdiagnosis and illness progression.

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.

Disseminated cryptococcosis mimicking malignant lymphoma on 18F-FDG PET/CT: A case report

RATIONALE

Disseminated cryptococcosis is extremely rare and is easily misdiagnosed as a malignant lymphoma. 18F-Fluorodeoxyglucose Positron Emission Tomography (PET)/ computed tomography (CT) may be useful to assess the involvement of disseminated cryptococcosis and to evaluate residual disease after treatment.

PATIENT CONCERNS

A 21-years-old man presented with fever and cough for a month, with multiple red nodules scattered on the skin. 18F- Fluorodeoxyglucose PET/CT revealed multiple hypermetabolic lymph nodes in the upper and lower parts of the diaphragmatic region and hypermetabolic nodules in the skin. According to the PET/CT results, malignant lymphoma was considered a possibility, especially T-cell lymphoma involving the skin.

DIAGNOSIS

Cryptococcosis was diagnosed using inguinal lymph node biopsy and blood culture.

INTERVENTIONS

The patient received two months of amphotericin B, fluconazole, and half a month of meropenem.

OUTCOMES

The patient's body temperature returned to normal and the red nodules on the skin disappeared. Most of the hypermetabolic enlarged lymph nodes disappeared, which was confirmed by reexamination with PET/CT.

LESSONS

Disseminated cryptococcosis is easily misdiagnosed as malignant lymphoma, especially when the lymph nodes are more involved. When multiple hypermetabolic enlarged lymph nodes appear on PET/CT, except for lymphoma, specific infections should also be considered.

Chronic disseminated cryptococcosis without meningeal involvement in a severely immunosuppressed HIV-infected patient successfully treated with fluconazole

A 43-year-old female with advanced HIV infection presented with two chronic skin lesions. Cutaneous cryptococcosis was confirmed and pulmonary cryptococcosis was suspected. The patient was neurologically asymptomatic and the cerebrospinal fluid cryptococcal antigen lateral flow assay was negative. She received oral fluconazole and had resolution of the skin lesions and significant improvement of the lung lesions. We report a person with AIDS with chronic disseminated cryptococcosis without meningeal involvement successfully treated with oral fluconazole.

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.

Supplementary benefits of CT-guided transthoracic lung aspiration biopsy for core needle biopsy

Objective

This study aimed to investigate the diagnostic efficacy of computed tomography (CT)-guided transthoracic lung core needle biopsy combined with aspiration biopsy and the clinical value of this combined routine microbial detection.

Materials and methods

We retrospectively collected the electronic medical records, CT images, pathology, and other data of 1085 patients with sequential core needle biopsy and aspiration biopsy of the same lung lesion under CT guidance in the First Affiliated Hospital of Wenzhou Medical University from January 2016 to January 2021. GenXpert MTB/RIF detection and BD BACTEC™ Mycobacterium/fungus culture were applied to identifying the microbiological results of these patients. We then compared the positive diagnostic rate, false negative rate, and diagnostic sensitivity rate of three methods including core needle biopsy alone, aspiration biopsy alone, and both core needle biopsy and aspiration biopsy.

Results

The pathological results of cutting histopathology and aspiration of cell wax were examined for 1085 patients. The diagnostic rates of cutting and aspiration pathology were 90.1% (978/1085) and 86.3% (937/1085), respectively, with no significant difference (P > 0.05). Considering both cutting and aspiration pathologies, the diagnostic rate was significantly improved, up to 98% (1063/1085) (P < 0.001). A total of 803 malignant lesions were finally diagnosed (803/1085, 74.0%). The false negative rate by cutting pathology was 11.8% (95/803), which was significantly lower than that by aspiration biopsy [31.1% (250/803), P < 0.001]. Compared with core needle biopsy alone, the false negative rate of malignant lesions decreased to 5.6% (45/803) (P < 0.05). Next, the aspirates of the malignant lesions highly suspected of corresponding infection were cultured. The results showed that 16 cases (3.1%, 16/511) were infected with Mycobacterium tuberculosis complex, Aspergillus niger, and Acinetobacter baumannii, which required clinical treatment. 803 malignant tumors were excluded and 282 cases of benign lesions were diagnosed, including 232 cases of infectious lesions (82.3%, 232/282). The diagnostic rate of Mycobacterium/fungus culture for infectious lesions by aspiration biopsy (47.4%) was significantly higher than that by lung core needle biopsy (22.8%; P < 0.001). The diagnostic rate of aspiration biopsy combined with core needle biopsy was 56% (130/232). The parallel diagnostic rate of aspirated biopsy for GenXpert detection and Mycobacterium/fungal culture combined with core needle biopsy was 64.7% (150/232), which was significantly higher than that of lung core needle biopsy alone (P < 0.001). Finally, pulmonary tuberculosis was diagnosed in 90 cases (38.8%) of infectious lesions. Compared with the sensitivity of core needle biopsy to detect tuberculosis (27.8%, 25/90), the sensitivity of aspirating biopsy for GenXpert detection and Mycobacterium/fungal culture was significantly higher, at 70% (63/90) and 56.7% (51/90), respectively. Although there was no significant difference in the sensitivity of aspirated biopsy for GenXpert and Mycobacterium/fungal culture to detect pulmonary tuberculosis, the sensitivity was significantly increased to 83.3% (P < 0.05) when the two tests were combined. Moreover, when aspirated biopsies were combined with GenXpert detection, Mycobacterium/fungus culture, and core needle biopsy, the sensitivity was as high as 90% (81/90).

Conclusion

CT-guided lung aspiration biopsy has a significant supplementary effect on core needle biopsies, which is indispensable in clinical application. Additionally, the combination of aspiration biopsy and core needle biopsy can significantly improve the diagnostic rate of benign and malignant lesions. Aspiration biopsy showed that pulmonary malignant lesions are complicated with pulmonary tuberculosis, aspergillus, and other infections. Finally, the diagnostic ability of lung puncture core needle biopsy and aspiration biopsy combined with routine microbial detection under CT positioning in the diagnosis of pulmonary infectious diseases was significantly improved.

Cryptococcus gattii: A Poseur to Behold!

Cryptococcosis is an invasive systemic mycosis caused by Cryptococcus, a genus of yeast. Causative organisms for human cryptococcosis include Cryptococcus neoformans and Cryptococcus gattii. Disease due to C.neoformans is conventionally seen in patients with underlying immunosuppression, whereas C.gattii-related infection is usually seen in immunocompetent people. The fact that the infection can occur among otherwise healthy individuals underscores the importance of having a necessary understanding of the pathophysiology and clinical and radiological presentations of the disease. We report a case of disseminated pulmonary and central nervous system (CNS) cryptococcosis in an apparently immunocompetent individual with unusual radiological findings necessitating probing for alternative diagnoses. We have attempted to supplement and revise the existing data on the radiological manifestations of C.gattii.

Primary Cutaneous Cryptococcosis Caused by Cryptococcus gatti in an Elderly Patient

According to the spread of Cryptococcus sp., fungal infections can be classified as primary or secondary. In primary cutaneous cryptococcosis, the fungi are restricted to the skin of the patients, without systemic involvement. The incidence of primary cutaneous cryptococcosis is high in patients with immunosuppression, and this type of infection is rarely observed in patients who are immunocompetent. In the present case report, a patient who is immunocompetent and has systemic comorbidity reported that, after skin trauma, ulcerovegetative lesions appeared in the right upper arm; the etiologic agent was identified as Cryptococcus gatti, serotype B. The cutaneous lesions healed completely after 5 months of fluconazole treatment.

Clinical Diagnosis, Treatment, and Laboratory Detection of 50 Cases of Pulmonary Cryptococcosis

Objective

This study retrospectively analyzed the clinical diagnosis, treatment process, and laboratory test data of patients with pulmonary cryptococcosis to improve the understanding and diagnosis and treatment ability of the disease.

Methods

Patients with pulmonary cryptococcosis diagnosed in the First Affiliated Hospital of Dalian Medical University from October 2003 to July 2021 were selected, and their medical records were consulted. The general data, clinical manifestations, laboratory examinations, imaging characteristics, diagnosis, and treatment methods were studied. The software SPSS 22 was used for statistical analysis.

Results

A total of 50 patients with pulmonary cryptococcosis were included in the study. The ratio of male to female was 1 : 1. The average age was 53.56 ± 11.99 years with a range of 27-82 years. Grouping the patients by age, with 10 years as an age group, we found that 40-60 years was the high-incidence age group. Two patients (4%) had a history of bird contact, and 18 patients (36%) had at least one underlying conditions. Hypertension and cough were the most common underlying condition and clinical manifestation, respectively. The main admission diagnoses were lung shadow (19/50, 38%) and chest/lung mass (15/50, 30%). In the imaging findings, the most common type of lesions was nodule/nodule shadow (29/69, 42.03%). Lesion distribution in the lower lobe, single lobe, and right lung was more frequent than that in the upper lobe, multilobes, and left lung, respectively. Burr sign (12/43, 27.91%) was the most common concomitant sign. Pulmonary ventilatory defect was found in 7 cases. Laboratory test results were largely nonspecific. The pathological examination showed granuloma, with 47 cases (94%) confirmed by postoperative biopsy. Two cases (4%) were confirmed by serology. One case (2%) was diagnosed with Cryptococcus smear. 43 cases (86%) were treated with simple surgical resection, 6 cases (12%) were treated with antifungal drugs, and 1 case (2%) was transferred to another hospital for suspicion of pulmonary tuberculosis.

Conclusions

Pulmonary cryptococcosis is more common in the middle-aged and elderly, and the clinical specificity is low. It can occur in people with normal or impaired immune function. The main clinical and imaging manifestation is cough and pulmonary nodules, which are very easy 5to be misdiagnosed. Surgical resection is the primary treatment.

Pulmonary Cryptococcosis Diagnosed by Metagenomic Next-Generation Sequencing in a Young Patient With Normal Immune Function: A Case Report

Background

Pulmonary cryptococcosis (PC) is a serious opportunistic fungal infection that usually occurs in immunocompromised patients. This disease is often difficult to diagnose in time due to its clinical manifestations and radiological feature similar to other pulmonary infections, as well as the low sensitivity of conventional diagnostic methods. Cryptococcosis in immune-competent patients is rare.

Case Presentation

Here we report a case of PC in an immune-competent patient. Tuberculosis was suspected according to radiological features due to the positive T-lymphocyte spot test and pure protein derivative skin test. To further detect the pathogen, bronchoalveolar lavage fluid (BALF) was collected for metagenomic next-generation sequencing (mNGS). Cryptococcus neoformans (one specific read) was identified by mNGS, indicating the PC of this patient. The following BALF culture and cryptococcal antigen lateral flow assay (CrAg-LFA) test also showed Cryptococcus infection, confirming the mNGS detection. Voriconazole (0.4 g daily) was given orally according to the subsequent susceptibility results. After seven months of treatment, the patient's condition improved.

Conclusion

Metagenomic next-generation sequencing (mNGS) is a better diagnostic tool to help clinicians distinguish pulmonary cryptococcosis from other atypical pulmonary infections.

Performance of the Colloidal Gold Immunochromatography of Cryptococcal Antigen on Bronchoalveolar Lavage Fluid for the Diagnosis of Pulmonary Cryptococcosis

Objective

This study aimed to investigate the efficacy of the colloidal gold immunochromatography method in the detection of Cryptococcus antigen in bronchoalveolar lavage fluid (BALF) for pulmonary cryptococcosis (PC) diagnosis.

Methods

A total of 111 patients with clinically suspected PC who were finally diagnosed with nonhuman immunodeficiency virus infection and hospitalized in the Ningbo First Hospital from March 2017 to December 2021 were retrospectively analyzed. All the confirmed cases were divided into two groups as follows: the PC group (33 cases) and the non-PC group (78 cases). All the patients were subjected to serum and BALF cryptococcal capsular polysaccharide antigen-lateral flow immunochromatographic assay (CrAg-LFA) and etiological culturing.

Results

In the PC group, serum CrAg-LFA was positive for 24 and negative for 9 cases, serum Cryptococcus culture was positive for 1 and negative for 32 cases, BALF CrAg-LFA was positive for 31 and negative for 2 cases, and BALF Cryptococcus culture was positive for 9 and negative for 24 cases. In the non-PC group, serum CrAg-LFA was positive for 1 and negative for 77 cases, serum culture was negative in all the cases, and both BALF CrAg-LFA and culture were negative in all the cases. The sensitivity, specificity, and accuracy of BALF CrAg-LFA for PC diagnosis were 93.9%, 100%, and 98.2%, respectively, whereas those of BALF culture were 27.3%, 100%, and 78.4%, respectively. The sensitivity and accuracy of BALF CrAg-LFA were higher than that of serum CrAg-LFA and BALF etiological culture with statistically significant differences (p < 0.05).

Conclusion

The diagnostic value of BALF CrAg-LFA for PC is superior to that of serum CrAg-LFA and BALF etiological culture.

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.

Structure-Guided Synthesis of FK506 and FK520 Analogs with Increased Selectivity Exhibit In Vivo Therapeutic Efficacy against Cryptococcus

Calcineurin is an essential virulence factor that is conserved across human fungal pathogens, including Cryptococcus neoformans, Aspergillus fumigatus, and Candida albicans. Although an excellent target for antifungal drug development, the serine-threonine phosphatase activity of calcineurin is conserved in mammals, and inhibition of this activity results in immunosuppression. FK506 (tacrolimus) is a naturally produced macrocyclic compound that inhibits calcineurin by binding to the immunophilin FKBP12. Previously, our fungal calcineurin-FK506-FKBP12 structure-based approaches identified a nonconserved region of FKBP12 that can be exploited for fungus-specific targeting. These studies led to the design of an FK506 analog, APX879, modified at the C-22 position, which was less immunosuppressive yet maintained antifungal activity. We now report high-resolution protein crystal structures of fungal FKBP12 and a human truncated calcineurin-FKBP12 bound to a natural FK506 analog, FK520 (ascomycin). Based on information from these structures and the success of APX879, we synthesized and screened a novel panel of C-22-modified compounds derived from both FK506 and FK520. One compound, JH-FK-05, demonstrates broad-spectrum antifungal activity in vitro and is nonimmunosuppressive in vivo. In murine models of pulmonary and disseminated C. neoformans infection, JH-FK-05 treatment significantly reduced fungal burden and extended animal survival alone and in combination with fluconazole. Furthermore, molecular dynamic simulations performed with JH-FK-05 binding to fungal and human FKBP12 identified additional residues outside the C-22 and C-21 positions that could be modified to generate novel FK506 analogs with improved antifungal activity. IMPORTANCE Due to rising rates of antifungal drug resistance and a limited armamentarium of antifungal treatments, there is a paramount need for novel antifungal drugs to treat systemic fungal infections. Calcineurin has been established as an essential and conserved virulence factor in several fungi, making it an attractive antifungal target. However, due to the immunosuppressive action of calcineurin inhibitors, they have not been successfully utilized clinically for antifungal treatment in humans. Recent availability of crystal structures of fungal calcineurin-bound inhibitor complexes has enabled the structure-guided design of FK506 analogs and led to a breakthrough in the development of a compound with increased fungal specificity. The development of a calcineurin inhibitor with reduced immunosuppressive activity and maintained therapeutic antifungal activity would add a significant tool to the treatment options for these invasive fungal infections with exceedingly high rates of mortality.

Essential Oils in Respiratory Mycosis: A Review

Respiratory mycosis is a major health concern, due to the expanding population of immunosuppressed and immunocompromised patients and the increasing resistance to conventional antifungals and their undesired side-effects, thus justifying the development of new therapeutic strategies. Plant metabolites, namely essential oils, represent promising preventive/therapeutic strategies due to their widely reported antifungal potential. However, regarding fungal infections of the respiratory tract, information is disperse and no updated compilation on current knowledge is available. Therefore, the present review aims to gather and systematize relevant information on the antifungal effects of several essential oils and volatile compounds against the main type of respiratory mycosis that impact health care systems. Particular attention is paid to Aspergillus fumigatus, the main pathogen involved in aspergillosis, Candida auris, currently emerging as a major pathogen in certain parts of the world, and Cryptococcus neoformans, one of the main pathogens involved in pulmonary cryptococcosis. Furthermore, the main mechanisms of action underlying essential oils’ antifungal effects and current limitations in clinical translation are presented. Overall, essential oils rich in phenolic compounds seem to be very effective but clinical translation requires more comprehensive in vivo studies and human trials to assess the efficacy and tolerability of these compounds in respiratory mycosis.

Computed tomography-based radiomics for identifying pulmonary cryptococcosis mimicking lung cancer

BACKGROUND

Pulmonary cryptococcosis (PC) is an invasive pulmonary fungal disease, and nodule/mass-type PC may mimic lung cancer (LC) in imaging appearance. Thus, an accurate diagnosis of nodule/mass-type PC is beneficial for appropriate management. However, the differentiation of nodule/mass-type PC from LC through computed tomography (CT) is still challenging.

PURPOSE

To develop and externally test a CT-based radiomics model for differentiating nodule/mass-type PC from LC.

METHODS

In this retrospective study, patients with nodule/mass-type PC or LC who underwent non-enhanced chest CT were included: institution 1 was for the training set, and institutions 2 and 3 were for the external test set. Large quantities of radiomics features were extracted. The radiomics score (Rad-score) was calculated using the linear discriminant analysis, and a subsequent 5-fold cross-validation was performed. A combined model was developed by incorporating Rad-score and clinical factors. Finally, the models were tested with an external test set and compared using the area under the receiver operating characteristic curve (AUC).

RESULTS

A total of 168 patients (45 with PC and 123 with LC) were in the training set, and 72 (36 with PC and 36 with LC) were in the external test set. Of the 81 patients with PC, 30 were immunocompromised (37%). Rad-score, comprised of 18 features, had an AUC of 0.844 after 5-fold cross-validation, which was lower than that (AUC = 0.943, P = 0.003) of the combined model integrating Rad-score, age, lobulation, pleural retraction, and patches. In the external test set, Rad-score and the combined model obtained good predictive performance (AUC = 0.824 for Rad-score, and 0.869 for the combined model). Moreover, the combined model outperformed the clinical model in the cross-validation and external test (0.943 vs. 0.810, P <0.001; 0.869 vs. 0.769, P = 0.011).

CONCLUSIONS

The proposed combined model exhibits a good differential diagnostic performance between nodule/mass-type PC and LC. The CT-based radiomics analysis has the potential to serve as an effective tool for the differentiation of nodule/mass-type PC from LC in clinical practice. This article is protected by copyright. All rights reserved.

Challenges in Serologic Diagnostics of Neglected Human Systemic Mycoses: An Overview on Characterization of New Targets

Systemic mycoses have been viewed as neglected diseases and they are responsible for deaths and disabilities around the world. Rapid, low-cost, simple, highly-specific and sensitive diagnostic tests are critical components of patient care, disease control and active surveillance. However, the diagnosis of fungal infections represents a great challenge because of the decline in the expertise needed for identifying fungi, and a reduced number of instruments and assays specific to fungal identification. Unfortunately, time of diagnosis is one of the most important risk factors for mortality rates from many of the systemic mycoses. In addition, phenotypic and biochemical identification methods are often time-consuming, which has created an increasing demand for new methods of fungal identification. In this review, we discuss the current context of the diagnosis of the main systemic mycoses and propose alternative approaches for the identification of new targets for fungal pathogens, which can help in the development of new diagnostic tests.

Grocott Methenamine Silver Staining Is the Optimal Approach to Histological Diagnosis of Pulmonary Cryptococcosis

Background

Histological staining methods for Cryptococcus identification vary in accuracy. This study aimed to investigate the clinical value of Grocott methenamine silver (GMS), periodic acid-Schiff (PAS), and Alcian blue (AB) staining in the diagnosis of pulmonary cryptococcosis (PC).

Methods

From April 2004 to June 2021, the clinical and pathological data of 152 patients with PC were collected from the Department of Pathology, Sun Yat-sen University Cancer Center. The sensitivity and identifiability of GMS, PAS, and AB staining for histological diagnosis were systematically evaluated using statistical methods combined with the microscopic characteristics of PC cases.

Results

Statistical analysis showed that the detection rates of GMS, PAS, and AB staining were 100.0% (152/152), 94.7% (144/152), and 81.6% (124/152), respectively. McNemar’s test showed that the sensitivity of GMS was significantly higher than those of PAS (P = 0.008) and AB stains (P < 0.001). Both PAS and AB stains had obvious non-specific staining, which interfered with the detection of Cryptococcus, and increased diagnostic difficulties. In contrast, in GMS staining, Cryptococcus spores were prominent with a clean background and were clearly observed at low or medium power magnification, with the identifiability significantly better than those of PAS or AB staining.

Conclusion

GMS staining had sensitivity up to 100%, and identifiability that was better than those of PAS and AB staining. GMS is the best method for histological diagnosis of PC.

Cryptococcal antigen testing of lung tissue homogenate improves pulmonary cryptococcosis diagnosis: Two case reports

BACKGROUND

Pulmonary cryptococcosis (PC) is an opportunistic infectious disease of the respiratory system. Lung tissue biopsies, culture of respiratory samples (e.g., sputum, lung tissue, pleural fluid, and bronchoalveolar lavage fluid), and cryptococcal antigen (CrAg) testing are helpful for a definitive diagnosis. However, these tests are sometimes falsely negative. PC is often misdiagnosed or underdiagnosed owing to the absence of obvert symptoms, poor imaging specificity, and false-negative laboratory tests.

CASE SUMMARY

We report two female patients who underwent computed tomography-guided percutaneous needle pulmonary biopsy of a lung nodule for a confirmed diagnosis. In both patients, the CrAg test on the lung biopsy tissue homogenate was positive, while the serum CrAg test was negative. Combined with the lung tissue pathology, we made the diagnosis of PC. Antifungal therapy was effective in both patients.

CONCLUSION

Given the findings of our cases and the literature review, lung tissue homogenate CrAg testing can be helpful in improving the diagnosis of PC.

A Velvet Transcription Factor Specifically Activates Mating through a Novel Mating-Responsive Protein in the Human Fungal Pathogen Cryptococcus deneoformans

Sexual reproduction facilitates infection by the production of both a lineage advantage and infectious sexual spores in the ubiquitous human fungal pathogen Cryptococcus deneoformans. However, the regulatory determinants specific for initiating mating remain poorly understood. Here, we identified a velvet family regulator, Cva1, that strongly promotes sexual reproduction in C. deneoformans. This regulation was determined to be specific, based on a comprehensive phenotypic analysis of cva1Δ under 26 distinct in vitro and in vivo growth conditions. We further revealed that Cva1 plays a critical role in the initiation of early mating events, including sexual cell-cell fusion, but is not important for the late sexual development stages or meiosis. Thus, Cva1 specifically contributes to mating activation. Importantly, a novel mating-responsive protein, Cfs1, serves as the key target of Cva1 during mating, since its absence nearly blocks cell-cell fusion in C. deneoformans and its sister species C. neoformans. Together, our findings provide insight into how C. deneoformans ensures the regulatory specificity of mating.

IMPORTANCE The human fungal pathogen C. deneoformans is a model organism for studying fungal sexual reproduction, which is considered to be important to infection. However, the specific regulatory determinants for activation of sexual reproduction remain poorly understood. In this study, by combining transcriptomic and comprehensive phenotypic analysis, we identified a velvet family regulator Cva1 that specifically and critically elicits early mating events, including sexual cell-cell fusion. Significantly, Cva1 induces mating through the novel mating-responsive protein Cfs1, which is essential for cell-cell fusion in C. deneoformans and its sister species C. neoformans. Considering that Cva1 and Cfs1 are highly conserved in species belonging to Cryptococcaeceae, they may play conserved and specific roles in the initiation of sexual reproduction in this important fungal clade, which includes multiple human fungal pathogens.