Overview of COVID-19-Associated Invasive Fungal Infection

Invasive Aspergillosis with Cavernous Sinus Thrombosis Following High-Dose Corticosteroid Therapy: A Challenging Case of Rhino-Orbital-Cerebral Mycosis

Invasive aspergillosis is a rare but severe fungal infection primarily affecting immunocompromised individuals. The Coronavirus Disease-2019 (COVID-19) pandemic has introduced new complexities in managing aspergillosis due to the widespread use of corticosteroids for treating COVID-19-related respiratory distress, which can increase susceptibility to fungal infections. Here, we present a challenging case of progressive cerebral aspergillosis complicated by cavernous sinus thrombosis (CST) in a 67-year-old male with a history of COVID-19. The patient, initially misdiagnosed with temporal arteritis, received pulse corticosteroid therapy twice before presenting with persistent left-sided headaches and vision loss. Cranial imaging revealed findings consistent with fungal sinusitis, Tolosa-Hunt syndrome, and orbital pseudotumor, which progressed despite initial antifungal therapy. Subsequent magnetic resonance imaging indicated an invasive mass extending into the left cavernous sinus and other intracranial structures, raising suspicion of aspergillosis. A transsphenoidal biopsy confirmed Aspergillus infection, leading to voriconazole therapy. Despite aggressive treatment, follow-up imaging revealed significant progression, with extension to the right frontal region and left cavernous sinus. The patient then developed visual impairment in the right eye and was diagnosed with CST secondary to fungal sinusitis. Management included a combination of systemic antifungals and antibiotics; however, the patient declined surgical intervention. This case underscores the diagnostic challenges and rapid progression associated with cerebral aspergillosis in post-COVID-19 patients treated with corticosteroids. This report highlights the need for heightened clinical suspicion and prompt, targeted interventions in similar cases to improve patient outcomes. Further research is required to understand the optimal management of invasive fungal infections.

Invasive Fungal Infections in Immunocompromised Conditions: Emphasis on COVID-19

The COVID-19 pandemic caused death of 6 million lives globally, primarily from respiratory failure, but also a significant number from invasive fungal co-infections in these patients, owing to the immune dysfunction in hospitalized patients. Such complications occurred more often in critically ill, hospitalized patients particularly those admitted in intensive care units and were reported as the major reason associated with a high mortality rate worldwide. Fungal pathogens most commonly associated with COVID-19 patients comprise members of the Mucorales (such as Rhizopus, Mucor, and Lichtheimia), as well as genera Aspergillus and Candida. In India, the prevalence rate of mucormycosis is relatively high than aspergillosis and candidiasis, and the predisposing risk factors associated with such infections included uncontrolled diabetes, underlying lung disease, leukopenia, neutropenia, malignancies and prolonged steroid therapy. However, co-infection with other fungi, including Alternaria and Scedosporium was also sporadically reported. These devastating invasive fungal infections are associated with differential mortality (high-low) and morbidity rates even after active management. The diagnosis of such infections is often challenging due to lack of sensitivity in contemporary diagnostic methods and poses an enormous challenge to healthcare experts. Thus, the role of early and accurate diagnosis, and management of such fungal infections, is vital in preventing life-threatening situations. Hence, this review focusses primarily on the epidemiology, predisposing risk factors, host environment, diagnosis and treatment of the most common medically important invasive fungal infections in immunocompromised conditions associated with COVID-19.

Is galactomannan a useful tool for triage and diagnosis of oral invasive aspergillosis?

OBJECTIVE

To evaluate the accuracy of the galactomannan serum test in diagnosing oral invasive aspergillosis.

METHODS

This prospective observational study included oncohematological neutropenic patients with suspected invasive aspergillosis, but without signs of pulmonary involvement. These patients underwent nasofibroscopy, biopsy, galactomannan serum testing, and maxillofacial high-resolution computed tomography to diagnose invasive aspergillosis. Patients were divided into two groups: Group 1 consisted of those with proven invasive aspergillosis, while Group 2 included patients without proven invasive aspergillosis. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated.

RESULTS

Thirteen patients were included in Group 1 and four in Group 2. The sensitivity, specificity, positive predictive and negative predictive values were 0.69, 1.0, 1.0 and 0.5, respectively. Sensitivity was higher in cases with Aspergillus sinusitis than in cases with exclusive oral lesions (0.77 versus 0.5, respectively). The galactomannan serum test optical density index was higher in Group 1 (2.4; range 0.2-3.5) than in Group 2 (0.2; range: 0.1-0.3; P-value = 0.007.

CONCLUSIONS

The galactomannan serum test is a valuable tool for screening invasive aspergillosis, especially in cases with nasal or sinus involvement, but biopsy is still the gold standard for diagnosis.

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.

Post-COVID pulmonary fungal infections: An unanticipated predicament or a ticking time bomb? Clinico-microbiological profile of cases encountered during the second wave of COVID-19 pandemic at a teaching hospital in the Himalayas with a brief literature review

Introduction

This study attempts to generate preliminary data regarding post-COVID pulmonary fungal infections, namely, COVID-19-associated pulmonary aspergillosis (CAPA), COVID-19-associated pulmonary mucormycosis (CAPM), and mixed infections from the Himalayas and compares the micro-radio-clinical profile and outcomes of the affected patients.

Materials and Methods

A retrospective data analysis was conducted, where clinical profiles, microbiological and radiological reports, and outcomes of n = 16 patients of post-COVID pulmonary infections were compared.

Results

Of n = 16 patients, n = 7 had CAPA (n = 5 Aspergillus fumigatus, n = 1 Aspergillus flavus, and n = 1 Aspergillus niger), n = 5 CAPM (Rhizopus arrhizus), and n = 4 with mixed infections (n = 3 infected with Aspergillus fumigatus and Rhizopus spp. and n = 1 with Aspergillus flavus and Rhizopus arrhizus). Thick-walled cavitary lesions, air-fluid levels, and multiple centrilobular nodules were some of the common radiological findings reported among these patients.

Conclusion

The immuno-compromised state following COVID-19 infection and treatment might be responsible for the progression of regular exposure to the dense Himalayan vegetation into an invasive pulmonary fungal infection. Suspecting post-COVID pulmonary fungal infection is necessary for primary care physicians to ensure timely referral to higher centers. Mixed pulmonary fungal infections (coinfection with Aspergillus spp. and Rhizopus spp.) are also emerging as important sequelae of COVID-19.

Fungal pathogens and COVID-19

COVID-19 pandemic highlighted the complications of secondary fungal infections that occurred globally in severe cases of coronavirus disease managed in the intensive care units. Furthermore, varied underlying host factors, such as preexisting immunosuppression, the use of immunomodulatory agents, and invasive procedures predisposing lung tissues to fungal colonization and proliferation, caused increased susceptibility to fungal infections in COVID-19 patient populations. These invasive fungal infections directly impact the overall length of hospitalization and mortality. The most commonly reported fungal infections in patients with COVID-19 include aspergillosis, invasive candidiasis, and mucormycosis. An overall worldwide increase in the prevalence of candidiasis and aspergillosis was observed in COVID-19 patients , whereas outbreaks of mucormycosis were mainly recorded from India. Diagnostic challenges and limited antifungal treatment options make secondary fungal infections among COVID-19 patients more burdensome, which results in improper management and increased mortality.

Atypical imaging patterns during lung invasive mould diseases: lessons for clinicians

Imaging of pulmonary invasive mould diseases (IMDs), which represents a cornerstone in their work-up, is mainly based on computed tomography (CT). The purpose of this review is to discuss their CT features, mainly those related to aspergillosis and mucormycosis. We will especially focus on atypical radiological presentations that are increasingly observed among non-neutropenic emerging populations of patients at risk, such as those receiving novel anticancer therapies or those in the intensive care unit. We will also discuss the interest of other available imaging techniques, mainly positron emission tomography/CT, that may play a role in the diagnosis as well as evaluation of disease extent and follow-up. We will show that any new airway-centred abnormality or caveated lesion should evoke IMDs in mildly immunocompromised hosts. Limitations in their recognition may be due to potential underlying abnormalities that increase the complexity of interpretation of lung imaging, as well as the non-specificity of imaging features. In this way, the differentials of all morphological/metabolic aspects must be kept in mind for the optimal management of patients, as well as the benefit of evaluation of the vascular status.

Diagnosis and Outcomes of Fungal Co-Infections in COVID-19 Infections: A Retrospective Study

The SARS-CoV-2 pandemic has resulted in a public health emergency with unique complications such as the development of fungal co-infections. The diagnosis of fungal infections can be challenging due to confounding imaging studies and difficulty obtaining histopathology. In this retrospective study, 173 patients with COVID-19 receiving antifungal therapy due to concern for fungal co-infection were evaluated. Patient characteristics, clinical outcomes, and the utility of fungal biomarkers were then evaluated for continuation of antifungal therapy. Data were collected from the electronic health record (EPIC) and analyzed using SPSS (version. 28, IBM, Inc., Armonk, NY, USA) Data are presented as mean ± SD or percentages. A total of 56 COVID-19 patients were diagnosed with fungal co-infection and 117 COVID-19 + patients had no fungal infection. Significantly fewer female patients were in the fungal+ group compared to COVID-19 control patients (29% in fungal+ compared to 51% in controls p = 0.005). Fungal diagnostics were all significantly higher in fungal+ patients. These include 1,4-beta-D-glucan (BDG), fungal culture, and bronchoalveolar lavage galactomannan (BAL GM). Intensive care unit hospitalization, mechanical ventilation, and mortality in fungal+ patients with COVID-19 were significantly higher than in control patients. Finally, significantly more fungal+ patients received voriconazole, isavuconazonium, or amphotericin B therapies, whereas control patients received significantly more short-course fluconazole. COVID-19+ patients with fungal co-infection were significantly more likely to be in the ICU and mechanically ventilated, and they result in higher mortality compared to control COVID-19 patients. The use of fungal diagnostics markers were helpful for diagnosis.

Discovery and development of novel substituted monohydrazides as potent antifungal agents

Novel substituted monohydrazides synthesized for this study displayed broad-spectrum activity against various fungal strains, including a panel of clinically relevant Candida auris strains. The activity of these compounds was either comparable or superior to amphotericin B against most of the fungal strains tested. These compounds possessed fungistatic activity in a time-kill assay and exhibited no mammalian cell toxicity. In addition, they prevented the formation of fungal biofilms. Even after repeated exposures, the Candida albicans ATCC 10231 (strain A) fungal strain did not develop resistance to these monohydrazides.

COVID-19 Is an Independent Risk Factor for Detrimental Invasive Fungal Disease in Patients on Veno-Venous Extracorporeal Membrane Oxygenation: A Retrospective Study

Invasive fungal disease (IFD) is associated with the mortality of patients on extracorporeal membrane oxygenation (ECMO). Several risk factors for IFD have been identified in patients with or without ECMO. Here, we assessed the relevance of coronavirus disease (COVID-19) for the occurrence of IFD in patients on veno-venous (V-V) ECMO for respiratory failure. In a retrospective analysis of all ECMO cases between January 2013 and December 2022 (2020-2022 for COVID-19 patients), active COVID-19 and the type, timing and duration of IFD were investigated. Demographics, hospital, ICU length of stay (LoS), duration of ECMO, days on invasive mechanical ventilation, prognostic scores (Respiratory ECMO Survival Prediction (RESP) score, Charlson Comorbidity Index (CCI), Therapeutic Intervention Scoring System (TISS)-10, Sequential Organ Failure Assessment (SOFA) score and Simplified Acute Physiology Score (SAPS)-II) and length of survival were assessed. The association of COVID-19 with IFD was investigated using propensity score matching and uni- and multivariable logistic regression analyses. We identified 814 patients supported with ECMO, and 452 patients were included in further analyses. The incidence of IFD was 4.8% and 11.0% in patients without and with COVID-19, respectively. COVID-19 status represented an independent risk factor for IFD (OR 4.30; CI 1.72-10.85; p: 0.002; multivariable regression analysis). In patients with COVID-19, 84.6% of IFD was candidemia and 15.4% represented invasive aspergillosis (IA). All of these patients died. In patients on V-V ECMO, we report that COVID-19 is an independent risk factor for IFD, which is associated with a detrimental prognosis. Further studies are needed to investigate strategies of antifungal therapy or prophylaxis in these patients.

Fungal Infections Identified with Multiplex PCR in Severe COVID-19 Patients during Six Pandemic Waves

Background and Objectives: With an increasing number of severe COVID-19 cases presenting with secondary fungal infections, this study aimed to determine the prevalence of fungal co-infections in severe COVID-19 patients across the six waves, identify the most common fungal pathogens associated with severe COVID-19, and explore any potential links between patient characteristics, therapeutic strategies, and the prevalence and type of fungal infection. Materials and Methods: A retrospective analysis was conducted on severe COVID-19 patients admitted to the Infectious Diseases and Pulmonology Hospital, "Victor Babes", Romania, between March 2020 and August 2022. Samples were collected from respiratory specimens, blood, and urine, after which a standard nucleic acid extraction protocol was employed. Patients were divided into groups with and without fungal infections, identified using multiplex PCR. The groups were compared based on demographic data, comorbidities, pandemic wave number, and clinical outcomes. Results: Out of 288 patients, 96 (33.3%) had fungal infections, with Candida spp. being the most common. Patients with fungal infections had higher rates of obesity (35.4% vs. 21.4%, p = 0.010) and a higher Charlson comorbidity index (CCI > 2) (37.5% vs 25.0%, p = 0.027). Ventilator use was significantly higher in the fungal infection group (45.8% vs. 18.8%; p < 0.001), as was ICU admission (39.6% vs. 26.6%; p = 0.024) and mortality (32.3% vs 12.0%; p < 0.001). The distribution of different fungal species varied across the pandemic waves, with no statistical significance (p = 0.209). The mortality risk notably increased with the degree of drug resistance (OR for three or more drug resistances = 6.71, p < 0.001). The second, fourth, and fifth pandemic waves were significantly associated with higher mortality risk (OR = 3.72, 3.61, and 4.08, respectively, all p < 0.001). Aspergillus spp. and Mucor spp. infections were significantly associated with increased mortality risk (OR = 4.61 and 6.08, respectively, both p < 0.001). Conclusions: Our study indicates a significant presence of fungal co-infections among severe COVID-19 patients that is associated with increased morbidity and mortality, particularly in patients with drug-resistant infections. These findings underline the necessity for comprehensive diagnostic approaches and tailored treatment strategies in managing COVID-19 patients, especially during specific pandemic waves and in patients with particular fungal infections. Further research is required to understand the implications of these co-infections and their management.

Invasive pulmonary aspergillosis with candidiasis: usefulness of molecular and ultrastructural morphological analysis on FFPE tissue for invasive fungal infections

Invasive pulmonary aspergillosis (IPA) is one of the most frequent forms of invasive fungal infections (IFI); however, it is often difficult to identify the pathogenic fungal species and to select appropriate treatments for patients with IFI including IPA. Here, we describe the detailed pathophysiology of an autopsy case of severe respiratory failure due to IPA with candidiasis. The patient developed severe respiratory failure after influenza infection and died, and the autopsy revealed a mixed disease of IPA with candidiasis. In this study, in addition to the routine pathological examination, we further examined formalin-fixed paraffin-embedded (FFPE) tissues by scanning electron microscopy (SEM) and partial genomic DNA sequencing. Although optical microscopy alone was insufficient to identify the pathogenic organisms, SEM clearly depicted the characteristic morphology of Aspergillus sp. and Candida sp. as closely overlapping in a nested fashion, providing evidence of mixed infection of both fungal species in a focal site. The technique using FFPE tissue in combination with ultrastructural observation by SEM, elemental analysis by SEM-EDX, and DNA sequencing is promising for analyzing the pathophysiology of IFI.

Amphotericin B Pharmacokinetics: Inter-strain Differences in Rats Following Intravenous Administration of the Most Commonly Marketed Formulations of the Drug

Background

Amphotericin B (AmB) is the first-line drug to treat invasive fungal infections. However, its delivery to the body and clinical use faces many challenges because of its poor solubility, poor pharmacokinetics, and severe nephrotoxicity.

Objectives

Due to the necessity for designing safer and more effective nanocarriers for AmB and the importance of preclinical pharmacokinetic studies in evaluating these novel drug delivery systems, the present study was framed to explore the influence of rat strain on the pharmacokinetic profile of this drug.

Methods

Twenty-four Wistar and Sprague-Dawley (SD) rats were intravenously injected with 1 mg/kg AmB as Fungizone or AmBisome, which are the two most commonly marketed formulations of the drug. Blood samples were collected before and at regular intervals up to 24 h after administration. Drug concentration was analyzed by a validated HPLC method, and pharmacokinetic parameters were determined by the non-compartmental method.

Results

Irrespective of the type of formulation, the AUC0-t and AUC0-∞ values were significantly higher (P < 0.001), and Cl as an important PK parameter was markedly lower (P < 0.001) in SD rats compared to the Wistar strain. For Fungizone, the mean Cl values in SD and Wistar rats were 206.90 and 462.95 mL/h/kg (P < 0.001), respectively. The apparent volume of distribution (Vss) was also lower in SD rats compared to Wistar; however, for AmBisome, the difference in Vss was not statistically significant. Our further investigation suggested that the higher amount of total protein in the SD strain may justify the higher plasma concentrations and lower Cl and Vss of amphotericin B in this strain compared to the Wistar strain.

Conclusions

Overall, following intravenous administration of AmB, there were significant differences in the pharmacokinetic parameters of the drug between two rat strains for both formulations. The obtained data is important for correctly interpreting experimental data from different research groups.