Pulmonary aspergillosis and cryptococcosis as a complication of COVID-19

Description of Cryptococcosis Following SARS-CoV-2 Infection: A Disease Survey Through the Mycosis Study Group Education and Research Consortium (MSG-19)

BACKGROUND

Invasive fungal infections have been described throughout the COVID-19 pandemic. Cryptococcal disease after infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been reported in several isolated case reports and 1 larger case series. We sought to describe cryptococcal infections following SARS-CoV-2 through establishing a database to investigate underlying risk factors, disease manifestations, and outcomes.

METHODS

We created a crowdsourced call for cases solicited through the Mycoses Study Group Education and Research Consortium, the Centers for Disease Control and Prevention Emerging Infectious Diseases Network, and infectious diseases Twitter groups. Data were collected in a web-based and secure REDCap survey without personal identifiers.

RESULTS

Sixty-nine cases were identified and submitted by 29 separate institutional sites. Cryptococcosis was diagnosed a median of 22 days (interquartile range, 9-42 days) after SARS-CoV-2 infection. Mortality among those with available follow-up was 72% (26/36) for the immunocompetent group and 48% (15/31) for the immunocompromised group (likelihood ratio, 4.01; P = .045). We observed a correlation between disease manifestation (central nervous system infection, proven/probable disseminated disease, and respiratory) and mortality (P = .002).

CONCLUSIONS

The mortality rate of 59% for patients with cryptococcosis following SARS-CoV-2 is higher than that of modern Cryptococcus cohorts. There was an association between immunocompromised status and cryptococcal disease manifestations as well as mortality. Moreover, our series emphasizes the need for clinical and laboratory assessment of opportunistic infections beyond 30 days when concerning symptoms develop.

Case Report: Cryptococcal Meningitis in a Previously Immunocompetent Patient with Coronavirus Disease 2019

Cryptococcus neoformans infections occur most frequently in immunocompromised patients. Here, we report a case of cryptococcal meningitis in a previously immunocompetent 78-year-old female patient after treatment of COVID-19. Underlying diseases included hypertension, hyperlipidemia, and diabetes. The patient was critically ill and was treated with remdesivir, baricitinib, and dexamethasone. During hospitalization, her mental state changed, and C. neoformans was detected in the cerebrospinal fluid. She died despite receiving antifungal treatment. Treatment of COVID-19 may be a predisposing factor for C. neoformans infection. There is a need for concern and countermeasures for opportunistic fungal infections that may accompany COVID-19.

COVID-19 associated with cryptococcosis: a scoping review

Background

There is growing evidence of fungal infections associated with COVID-19. The development of cryptococcosis in these patients has been infrequently reported. However, it can be life-threatening.

Objective

To identify cases of COVID-19 patients who developed cryptococcosis and to compare baseline characteristics and management between those who survived and those who died.

Methods

We conducted a scoping review using PubMed, Scopus, Web of Science, and Embase to identify studies that reported patients with COVID-19 and cryptococcosis. No language restriction was applied. Single case reports, case series, and original articles were included. It is important to note that 'n' refers to the total number of individuals with the specified variable.

Results

A total of 58 studies were included. Among these studies, 51 included individual patient data, detailing information on a total of 65 patients, whereas eight studies reported the proportion of cryptococcosis in COVID-19 patients. One study provided both individual and aggregate case information. From individual patient data, the majority were male (73.9%; n = 48) with a median age of 60 years (range: 53-70). Severe COVID-19 and multiple comorbidities, led by arterial hypertension and diabetes mellitus, were frequently reported, but few had classic immunosuppression factors. On the other hand, HIV status, either negative or positive, was reported in just over half of the patients (61.5%; n = 40). Most were admitted to the intensive care unit (ICU) (58.5%; n = 31), received mechanical ventilation (MV) (50.0%; n = 26), and developed disseminated cryptococcosis (55.4%; n = 36). Secondary infection, mainly bacterial, was reported in 19 patients (29.2%). Mortality was 47.7% (n = 31). Of the studies that reported the proportion of cryptococcosis in COVID-19 cases, the majority were descriptive studies published as conference abstracts.

Conclusion

Cryptococcosis in COVID-19 patients has been reported more frequently. However, it is still not as common as other fungal infections associated with COVID-19. Few patients have some classic immunosuppression factors. The factors associated with mortality were male sex, age, ICU admission, MV, secondary infections, and lymphopenia.

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.

COVID-19 Associated with Cryptococcosis: A New Challenge during the Pandemic

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a great threat to global health. In addition to SARS-CoV-2 itself, clinicians should be alert to the possible occurrence of co-infection or secondary infection among patients with COVID-19. The possible co-pathogens include bacteria, viruses, and fungi, but COVID-19-associated cryptococcosis is rarely reported. This review provided updated and comprehensive information about this rare clinical entity of COVID-19-associated cryptococcosis. Through an updated literature search till 23 August 2022, we identified a total of 18 culture-confirmed case reports with detailed information. Half (n = 9) of them were elderly. Fifteen (83.3%) of them had severe COVID-19 and ever received systemic corticosteroid. Disseminated infection with cryptococcemia was the most common type of cryptococcosis, followed by pulmonary and meningitis. Except one case of C. laurentii, all other cases are by C. neoformans. Liposomal amphotericin B and fluconazole were the most commonly used antifungal agents. The overall mortality was 61.1% (11/18) and four of them did not receive antifungal agents before death. Improving the poor outcome requires a physician's high suspicion, early diagnosis, and prompt treatment.

Comparative risk assessment of COVID-19 associated mucormycosis and aspergillosis: A systematic review

COVID-19 is not only limited to a defined array but also has expanded with several secondary infections. Two uncommon opportunistic fungal infections, COVID-19 associated mucormycosis (CAM) and aspergillosis (CAA), have recently been highly acquainted by many worldwide cases. Two immune response deteriorating factors are considered to be responsible for immunosuppression: comorbidities and medication. Due to unlike infection sites and patterns, CAM and CAA-associated factors deflect a few degrees of proximity, and the present study is for its assessment. The study evaluated 351 CAM cases and 191 CAA cases retrieved from 65 and 53 articles based on inclusion criteria, respectively. Most of the CAM reported from India and CAA were from four South-European and West-European neighbor countries. The mean ages of CAM and CAA were 52.72 ± 13.74 and 64.81 ± 11.14, correspondingly. Mortality of CAA (56.28%) was two times greater than CAM (26.02%). Nevertheless, the count of diabetes cases was very high in CAM compared to CAA. The main comorbidities of CAM were diabetes (nearly 80%) and hypertension (more than 38%). All noticeable complications were higher in CAA except diabetes, and these were diabetes (34.55%), hypertension (45.03%), and obesity (18.32%). Moreover, pre-existing respiratory complications like asthma and chronic obstructive pulmonary disease are visible in CAA. The uses of steroids in CAM and CAA were nearly 70% and 66%, respectively. Almost one-fourth of CAA cases were reported using immunosuppressant monoclonal antibodies, whereas only 7.69% were for CAM. The overall finding highlights diabetes, hypertension, and steroids as the risk factors for CAM, whereas obesity, chronic pulmonary disease, and immunosuppressants for CAA.

Pulmonary cryptococcosis after recovery from COVID-19 in an immunocompetent patient: A rare case report

RATIONALE

Cryptococcus neoformans (C neoformans) infection typically occurs in immunocompromised patients infected with human immunodeficiency virus (HIV), or those taking immunosuppressive drugs, corticosteroids, or chemotherapy. Recently, there have been an increasing number of reports of cryptococcosis as opportunistic infections in COVID-19 patients, all of which have been related to immunocompromising conditions, underlying medical diseases, immune suppression drugs, or corticosteroids. Here, we report the first case of pulmonary cryptococcosis in an immunocompetent patient with a history of COVID-19 who had no history of underlying diseases or immune modulation drugs.

PATIENT CONCERNS

A previously healthy 46-year-old man presented with tiny lung nodules. He had quit smoking 6 years prior. He had no significant medical history except for COVID-19 3 months prior, and had not received corticosteroids or cytokine blockers when he had COVID-19. He had been coughing since he recovered from COVID-19.

DIAGNOSIS

Bronchoalveolar lavage cultures showed the growth of C neoformans. A CT-guided percutaneous needle biopsy of the lung lesion was performed. Histopathology of the biopsy specimen showed granulomas with encapsulated yeast. There was no growth of C neoformans in the CSF or blood. He was diagnosed with pulmonary cryptococcosis.

INTERVENTION

Antifungal drug (fluconazole) was administered for 6 months in the outside clinic.

OUTCOMES

The lung lesions disappeared after 6 months medication.

LESSONS

This case may illustrate the risk of pulmonary cryptococcosis after SARS-CoV-2 infection in an immunocompetent patient. Opportunistic infections can occur even after recovery from COVID-19 for several reasons. First, SARS-CoV-2 infection causes immune dysregulation including lymphocytopenia. Second, T lymphocytes play a principal role against Cryptococcus. Third, these changes in the immune system due to COVID-19 may last for several weeks. Thus, we suggest careful consideration of lung lesions in patients with a history of COVID-19.

Overview of COVID-19-Associated Invasive Fungal Infection

Purpose of Review

Invasive fungal infections are a complication of COVID-19 disease. This article reviews literature characterizing invasive fungal infections associated with COVID-19.

Recent Findings

Multiple invasive fungal infections including aspergillosis, candidiasis, pneumocystosis, other non-Aspergillus molds, and endemic fungi have been reported in patients with COVID-19. Risk factors for COVID-19-associated fungal disease include underlying lung disease, diabetes, steroid or immunomodulator use, leukopenia, and malignancy. COVID-19-associated pulmonary aspergillosis (CAPA) and COVID-19-associated mucormycosis (CAM) are the most common fungal infections described. However, there is variability in the reported incidences related to use of differing diagnostic algorithms.

Summary

Fungal pathogens are important cause of infection in patients with COVID-19, and the diagnostic strategies continue to evolve. Mortality in these patients is increased, and providers should operate with a high index of suspicion. Further studies will be required to elucidate the associations and pathogenesis of these diseases and best management and prevention strategies.

Screening of the Pandemic Response Box Reveals an Association between Antifungal Effects of MMV1593537 and the Cell Wall of Cryptococcus neoformans, Cryptococcus deuterogattii, and Candida auris

There is an urgent unmet need for novel antifungals. In this study, we searched for novel antifungal activities in the Pandemic Response Box, a collection of 400 structurally diverse compounds in various phases of drug discovery. We identified five molecules which could control the growth of Cryptococcus neoformans, Cryptococcus deuterogattii, and the emerging global threat Candida auris. After eliminating compounds which demonstrated paradoxical antifungal effects or toxicity to mammalian macrophages, we selected compound MMV1593537 as a nontoxic, fungicidal molecule for further characterization of antifungal activity. Scanning electron microscopy revealed that MMV1593537 affected cellular division in all three pathogens. In Cryptococcus, MMV1593537 caused a reduction in capsular dimensions. Treatment with MMV1593537 resulted in increased detection of cell wall chitooligomers in these three species. Since chitooligomers are products of the enzymatic hydrolysis of chitin, we investigated whether surface chitinase activity was altered in response to MMV1593537 exposure. We observed peaks of enzyme activity in C. neoformans and C. deuterogattii in response to MMV1593537. We did not detect any surface chitinase activity in C. auris. Our results suggest that MMV1593537 is a promising, nontoxic fungicide whose mechanism of action, at least in Cryptococcus spp, requires chitinase-mediated hydrolysis of chitin. IMPORTANCE The development of novel antifungals is a matter of urgency. In this study, we evaluated antifungal activities in a collection of 400 molecules, using highly lethal fungal pathogens as targets. One of these molecules, namely, MMV1593537, was not toxic to host cells and controlled the growth of isolates of Cryptococcus neoformans, C. deuterogattii, C. gattii, Candida auris, C. albicans, C. parapsilosis, and C. krusei. We tested the mechanisms of antifungal action of MMV1593537 in the Cryptococcus and C. auris models and concluded that the compound affects the cell wall, a structure which is essential for fungal life. At least in Cryptococcus, this effect involved chitinase, an enzyme which is required for remodeling the cell wall. Our results suggest that MMV1593537 is a candidate for future antifungal development.

Tendency in Pulmonary Aspergillosis Investigation during the COVID-19 Era: What Is Changing?

Aspergillosis is a disease caused by Aspergillus, and invasive pulmonary aspergillosis (IPA) is the most common invasive fungal infection leading to death in severely immuno-compromised patients. The literature reports Aspergillus co-infections in patients with COVID-19 (CAPA). Diagnosing CAPA clinically is complex since the symptoms are non-specific, and performing a bronchoscopy is difficult. Generally, the microbiological diagnosis of aspergillosis is based on cultural methods and on searching for the circulating antigens galactomannan and 1,3-β-D-glucan in the bronchoalveolar lavage fluid (bGM) or serum (sGM). In this study, to verify whether the COVID-19 period has stimulated clinicians to pay greater attention to IPA in patients with respiratory tract infections, we evaluated the number of requests for GM-Ag research and the number of positive tests found during the pre-COVID-19 and COVID-19 periods. Our data show a significant upward trend in GM-Ag requests and positivity from the pre-COVID to COVID period, which is attributable in particular to the increase in IPA risk factors as a complication of COVID-19. In the COVID period, parallel to the increase in requests, the number of positive tests for GM-Ag also increased, going from 2.5% in the first period of 2020 to 12.3% in the first period of 2021.

Three Models of Vaccination Strategies Against Cryptococcosis in Immunocompromised Hosts Using Heat-Killed Cryptococcus neoformans Δsgl1

Vaccines are one of the greatest medical accomplishments to date, yet no fungal vaccines are currently available in humans mainly because opportunistic mycoses generally occur during immunodeficiencies necessary for vaccine protection. In previous studies, a live, attenuated Cryptococcus neoformans Δsgl1 mutant accumulating sterylglucosides was found to be avirulent and protected mice from a subsequent lethal infection even in absence of CD4⁺ T cells, a condition most associated with cryptococcosis (e.g., HIV). Here, we tested three strategies of vaccination against cryptococcosis. First, in our preventative model, protection was achieved even after a 3-fold increase of the vaccination window. Second, because live C. neoformans Δsgl1-vaccinated mice challenged more than once with WT strain had a significant decrease in lung fungal burden, we tested C. neoformans Δsgl1 as an immunotherapeutic. We found that therapeutic administrations of HK C. neoformans Δsgl1 post WT challenge significantly improves the lung fungal burden. Similarly, therapeutic administration of HK C. neoformans Δsgl1 post WT challenge resulted in 100% or 70% survival depending on the time of vaccine administration, suggesting that HK Δsgl1 is a robust immunotherapeutic option. Third, we investigated a novel model of vaccination in preventing reactivation from lung granuloma using C. neoformans Δgcs1. Remarkably, we show that administration of HK Δsgl1 prevents mice from reactivating Δgcs1 upon inducing immunosuppression with corticosteroids or by depleting CD4⁺ T cells. Our results suggest that HK Δsgl1 represents a clinically relevant, efficacious vaccine that confers robust host protection in three models of vaccination against cryptococcosis even during CD4-deficiency.

Invasive Respiratory Fungal Infections in COVID-19 Critically Ill Patients

Patients with coronavirus disease 19 (COVID-19) admitted to the intensive care unit (ICU) often develop respiratory fungal infections. The most frequent diseases are the COVID-19 associated pulmonary aspergillosis (CAPA), COVID-19 associated pulmonary mucormycosis (CAPM) and the Pneumocystis jirovecii pneumonia (PCP), the latter mostly found in patients with both COVID-19 and underlying HIV infection. Furthermore, co-infections due to less common mold pathogens have been also described. Respiratory fungal infections in critically ill patients are promoted by multiple risk factors, including epithelial damage caused by COVID-19 infection, mechanical ventilation and immunosuppression, mainly induced by corticosteroids and immunomodulators. In COVID-19 patients, a correct discrimination between fungal colonization and infection is challenging, further hampered by sampling difficulties and by the low reliability of diagnostic approaches, frequently needing an integration of clinical, radiological and microbiological features. Several antifungal drugs are currently available, but the development of new molecules with reduced toxicity, less drug-interactions and potentially active on difficult to treat strains, is highly warranted. Finally, the role of prophylaxis in certain COVID-19 populations is still controversial and must be further investigated.

COVID-19-associated Cryptococcus infection (CACI): a review of literature and clinical pearls

Background

Cryptococcal infection has been increasingly reported in patients with COVID-19 infection, but the epidemiological factors, presentation, diagnostic certainty, and outcome have not been well-described.

Methods

We reviewed the published cases of COVID-19-associated Cryptococcus infections (CACI) to shed the light on the burden of this infection.

Results

We identified 13 patients with confirmed cryptococcal infection. Cryptococcus infection was primarily seen in patients with severe COVID-19 disease who received corticosteroids therapy and admitted to the intensive care unit. Pulmonary CACI was the most common reported infection followed by cryptococcal meningitis.

Conclusion

In light of the high mortality rate, clinicians should maintain a high clinical suspicion of CACI in critically ill patients.

Invasive cryptococcal disease in COVID-19: systematic review of the literature and analysis

During the Coronavirus Disease 2019 (COVID-19) pandemic, an increasing number of fungal infections associated with SARS-CoV-2 infection have been reported. Among them, cryptococcosis could be a life-threatening disease. We performed a Systematic Review (PRISMA Statement) of cryptococcosis and COVID-19 co-infection, case report/series were included: a total of 34 cases were found, then we added our case report. We collected patients' data and performed a statistical analysis comparing two groups of patients sorted by outcome: "dead" and "alive". Three cases were excluded for lack of information. To compare categorical data, we used a Fisher-exact test (α=0.05). To compare quantitative variables a U Mann-Whitney test was used (α=0.05), with a 95% Confidence Interval. A total of 32 co-infected patients were included in the statistical analysis. Mortality rate was 17/32 (53.1%): these patients were included in "dead" group, and 15/32 (46.9%) patients survived and were included in "alive" group. Overall, males were 25/32 (78.1%), the median age was 60 years (IQR 53-70) with non-statistically significant difference between groups (p=0.149 and p=0.911, respectively). Three variables were associated with mortality: ARDS, ICU admission and inadequate treatment. Overall, 21 out of 24 (87.5%) patients were in ARDS with a statistically significant difference among two groups (p=0.028). ICU admission for COVID-19 was observed in 18/26 (69.2%), more frequently among dead group (p=0.034). Finally, 15/32 (46.9%) patients had adequate treatment (amphotericin B + flucytosine for invasive cryptococcosis) mostly among alive patients (p=0.039). In conclusion, mortality due to cryptococcal infection among COVID-19 patients remains high but an early diagnosis and appropriate treatment could reduce mortality.