The battle against fungi: lessons in antifungal stewardship from COVID 19 times

The COVID-19 pandemic has highlighted the detrimental effect of secondary pathogens in patients with a primary viral insult. In addition to superinfections with bacterial pathogens, invasive fungal infections were increasingly reported. The diagnosis of pulmonary fungal infections has always been challenging; however, it became even more problematic in the setting of COVID-19, particularly regarding the interpretation of radiological findings and mycology test results in patients with these infections. Moreover, prolonged hospitalization in ICU, coupled with underlying host factors. such as preexisting immunosuppression, use of immunomodulatory agents, and pulmonary compromise, caused additional vulnerability to fungal infections in this patient population. In addition, the heavy workload, redeployment of untrained staff, and inconsistent supply of gloves, gowns, and masks during the COVID-19 outbreak made it harder for healthcare workers to strictly adhere to preventive measures for infection control. Taken together, these factors favored patient-to-patient spread of fungal infections, such as those caused by Candida auris, or environment-to-patient transmission, including nosocomial aspergillosis. As fungal infections were associated with increased morbidity and mortality, empirical treatment was overly used and abused in COVID-19-infected patients, potentially contributing to increased resistance in fungal pathogens. The aim of this paper was to focus on essential elements of antifungal stewardship in COVID-19 for three fungal infections, COVID-19-associated candidemia (CAC), -pulmonary aspergillosis (CAPA), and -mucormycosis (CAM).

COVID-19-Associated Pulmonary Aspergillosis Isolates Are Genomically Diverse but Similar to Each Other in Their Responses to Infection-Relevant Stresses.

Secondary infections caused by the pulmonary fungal pathogen Aspergillus fumigatus are a significant cause of mortality in patients with severe coronavirus disease 19 (COVID-19). Even though epithelial cell damage and aberrant cytokine responses have been linked to susceptibility to COVID-19-associated pulmonary aspergillosis (CAPA), little is known about the mechanisms underpinning copathogenicity. Here, we analyzed the genomes of 11 A. fumigatus isolates from patients with CAPA in three centers from different European countries. CAPA isolates did not cluster based on geographic origin in a genome-scale phylogeny of representative A. fumigatus isolates. Phenotypically, CAPA isolates were more similar to the A. fumigatus A1160 reference strain than to the Af293 strain when grown in infection-relevant stresses, except for interactions with human immune cells wherein macrophage responses were similar to those induced by the Af293 reference strain. Collectively, our data indicate that CAPA isolates are genomically diverse but are more similar to each other in their responses to infection-relevant stresses. A larger number of isolates from CAPA patients should be studied to better understand the molecular epidemiology of CAPA and to identify genetic drivers of copathogenicity and antifungal resistance in patients with COVID-19. IMPORTANCE Coronavirus disease 2019 (COVID-19)-associated pulmonary aspergillosis (CAPA) has been globally reported as a life-threatening complication in some patients with severe COVID-19. Most of these infections are caused by the environmental mold Aspergillus fumigatus, which ranks third in the fungal pathogen priority list of the WHO. However, little is known about the molecular epidemiology of Aspergillus fumigatus CAPA strains. Here, we analyzed the genomes of 11 A. fumigatus isolates from patients with CAPA in three centers from different European countries, and carried out phenotypic analyses with a view to understanding the pathophysiology of the disease. Our data indicate that A. fumigatus CAPA isolates are genomically diverse but are more similar to each other in their responses to infection-relevant stresses.

Prognostic Impact of Bronchoalveolar Lavage Fluid Galactomannan and Aspergillus Culture Results on Survival in COVID-19 Intensive Care Unit Patients: a Post Hoc Analysis from the European Confederation of Medical Mycology (ECMM) COVID-19-Associated Pulmonary Aspergillosis Study.

Critically ill patients with coronavirus disease 2019 (COVID-19) may develop COVID-19-associated pulmonary aspergillosis (CAPA), which impacts their chances of survival. Whether positive bronchoalveolar lavage fluid (BALF) mycological tests can be used as a survival proxy remains unknown. We conducted a post hoc analysis of a previous multicenter, multinational observational study with the aim of assessing the differential prognostic impact of BALF mycological tests, namely, positive (optical density index of ≥1.0) BALF galactomannan (GM) and positive BALF Aspergillus culture alone or in combination for critically ill patients with COVID-19. Of the 592 critically ill patients with COVID-19 enrolled in the main study, 218 were included in this post hoc analysis, as they had both test results available. CAPA was diagnosed in 56/218 patients (26%). Most cases were probable CAPA (51/56 [91%]) and fewer were proven CAPA (5/56 [9%]). In the final multivariable model adjusted for between-center heterogeneity, an independent association with 90-day mortality was observed for the combination of positive BALF GM and positive BALF Aspergillus culture in comparison with both tests negative (hazard ratio, 2.53; 95% CI confidence interval [CI], 1.28 to 5.02; P = 0.008). The other independent predictors of 90-day mortality were increasing age and active malignant disease. In conclusion, the combination of positive BALF GM and positive BALF Aspergillus culture was associated with increased 90-day mortality in critically ill patients with COVID-19. Additional study is needed to explore the possible prognostic value of other BALF markers.

Risk factors and outcome of pulmonary aspergillosis in critically ill coronavirus disease 2019 patients-a multinational observational study by the European Confederation of Medical Mycology.

OBJECTIVES: Coronavirus disease 2019 (COVID-19) -associated pulmonary aspergillosis (CAPA) has emerged as a complication in critically ill COVID-19 patients. The objectives of this multinational study were to determine the prevalence of CAPA in patients with COVID-19 in intensive care units (ICU) and to investigate risk factors for CAPA as well as outcome. METHODS: The European Confederation of Medical Mycology (ECMM) conducted a multinational study including 20 centres from nine countries to assess epidemiology, risk factors and outcome of CAPA. CAPA was defined according to the 2020 ECMM/ISHAM consensus definitions. RESULTS: A total of 592 patients were included in this study, including 11 (1.9%) patients with histologically proven CAPA, 80 (13.5%) with probable CAPA, 18 (3%) with possible CAPA and 483 (81.6%) without CAPA. CAPA was diagnosed a median of 8 days (range 0-31 days) after ICU admission predominantly in older patients (adjusted hazard ratio (aHR) 1.04 per year; 95% CI 1.02-1.06) with any form of invasive respiratory support (HR 3.4; 95% CI 1.84-6.25) and receiving tocilizumab (HR 2.45; 95% CI 1.41-4.25). Median prevalence of CAPA per centre was 10.7% (range 1.7%-26.8%). CAPA was associated with significantly lower 90-day ICU survival rate (29% in patients with CAPA versus 57% in patients without CAPA; Mantel-Byar p < 0.001) and remained an independent negative prognostic variable after adjusting for other predictors of survival (HR 2.14; 95% CI 1.59-2.87, p ≤ 0.001). CONCLUSION: Prevalence of CAPA varied between centres. CAPA was significantly more prevalent among older patients, patients receiving invasive ventilation and patients receiving tocilizumab, and was an independent strong predictor of ICU mortality.