Genomic Diversity of Azole-Resistant Aspergillus fumigatus in the United States.

Azole resistance in pathogenic Aspergillus fumigatus has become a global public health issue threatening the use of medical azoles. The environmentally occurring resistance mutations, TR34/L98H (TR34) and TR46/Y121F/T289A (TR46), are widespread across multiple continents and emerging in the United States. We used whole-genome single nucleotide polymorphism (SNP) analysis on 179 nationally represented clinical and environmental A. fumigatus genomes from the United States along with 18 non-U.S. genomes to evaluate the genetic diversity and foundation of the emergence of azole resistance in the United States. We demonstrated the presence of clades of A. fumigatus isolates: clade A (17%) comprised a global collection of clinical and environmental azole-resistant strains, including all strains with the TR34/L98H allele from India, The Netherlands, the United Kingdom, and the United States, and clade B (83%) consisted of isolates without this marker mainly from the United States. The TR34/L98H polymorphism was shared among azole-resistant A. fumigatus strains from India, The Netherlands, the United Kingdom, and the United States, suggesting the common origin of this resistance mechanism. Six percent of azole-resistant A. fumigatus isolates from the United States with the TR34 resistance marker had a mixture of clade A and clade B alleles, suggestive of recombination. Additionally, the presence of equal proportions of both mating types further suggests the ongoing presence of recombination. This study demonstrates the genetic background for the emergence of azole resistance in the United States, supporting a single introduction and subsequent propagation, possibly through recombination of environmentally driven resistance mutations. IMPORTANCE Aspergillus fumigatus is one of the most common causes of invasive mold infections in patients with immune deficiencies and has also been reported in patients with severe influenza and severe acute respiratory syndrome coronavirus 2 (SARs-CoV-2). Triazole drugs are the first line of therapy for this infection; however, their efficacy has been compromised by the emergence of azole resistance in A. fumigatus, which was proposed to be selected for by exposure to azole fungicides in the environment [P. E. Verweij, E. Snelders, G. H. J. Kema, E. Mellado, et al., Lancet Infect Dis 9:789-795, 2009, https://doi.org/10.1016/S1473-3099(09)70265-8]. Isolates with environmentally driven resistance mutations, TR34/L98H (TR34) and TR46/Y121F/T289A (TR46), have been reported worldwide. Here, we used genomic analysis of a large sample of resistant and susceptible A. fumigatus isolates to demonstrate a single introduction of TR34 in the United States and suggest its ability to spread into the susceptible population is through recombination between resistant and susceptible isolates.

Genomic and Phenotypic Analysis of COVID-19-Associated Pulmonary Aspergillosis Isolates of Aspergillus fumigatus.

The ongoing global pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for coronavirus disease 2019 (COVID-19), first described in Wuhan, China. A subset of COVID-19 patients has been reported to have acquired secondary infections by microbial pathogens, such as opportunistic fungal pathogens from the genus Aspergillus. To gain insight into COVID-19-associated pulmonary aspergillosis (CAPA), we analyzed the genomes and characterized the phenotypic profiles of four CAPA isolates of Aspergillus fumigatus obtained from patients treated in the area of North Rhine-Westphalia, Germany. By examining the mutational spectrum of single nucleotide polymorphisms, insertion-deletion polymorphisms, and copy number variants among 206 genes known to modulate A. fumigatus virulence, we found that CAPA isolate genomes do not exhibit significant differences from the genome of the Af293 reference strain. By examining a number of factors, including virulence in an invertebrate moth model, growth in the presence of osmotic, cell wall, and oxidative stressors, secondary metabolite biosynthesis, and the MIC of antifungal drugs, we found that CAPA isolates were generally, but not always, similar to A. fumigatus reference strains Af293 and CEA17. Notably, CAPA isolate D had more putative loss-of-function mutations in genes known to increase virulence when deleted. Moreover, CAPA isolate D was significantly more virulent than the other three CAPA isolates and the A. fumigatus reference strains Af293 and CEA17, but similarly virulent to two other clinical strains of A. fumigatus. These findings expand our understanding of the genomic and phenotypic characteristics of isolates that cause CAPA. IMPORTANCE The global pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent of coronavirus disease 2019 (COVID-19), has already killed millions of people. COVID-19 patient outcome can be further complicated by secondary infections, such as COVID-19-associated pulmonary aspergillosis (CAPA). CAPA is caused by Aspergillus fungal pathogens, but there is little information about the genomic and phenotypic characteristics of CAPA isolates. We conducted genome sequencing and extensive phenotyping of four CAPA isolates of Aspergillus fumigatus from Germany. We found that CAPA isolates were often, but not always, similar to other reference strains of A. fumigatus across 206 genetic determinants of infection-relevant phenotypes, including virulence. For example, CAPA isolate D was more virulent than other CAPA isolates and reference strains in an invertebrate model of fungal disease, but similarly virulent to two other clinical strains. These results expand our understanding of COVID-19-associated pulmonary aspergillosis.

COVID-19-Associated Pulmonary Aspergillosis, March-August 2020.

Pneumonia caused by severe acute respiratory syndrome coronavirus 2 emerged in China at the end of 2019. Because of the severe immunomodulation and lymphocyte depletion caused by this virus and the subsequent administration of drugs directed at the immune system, we anticipated that patients might experience fungal superinfection. We collected data from 186 patients who had coronavirus disease-associated pulmonary aspergillosis (CAPA) worldwide during March-August 2020. Overall, 182 patients were admitted to the intensive care unit (ICU), including 180 with acute respiratory distress syndrome and 175 who received mechanical ventilation. CAPA was diagnosed a median of 10 days after coronavirus disease diagnosis. Aspergillus fumigatus was identified in 80.3% of patient cultures, 4 of which were azole-resistant. Most (52.7%) patients received voriconazole. In total, 52.2% of patients died; of the deaths, 33.0% were attributed to CAPA. We found that the cumulative incidence of CAPA in the ICU ranged from 1.0% to 39.1%.

SARS-CoV-2 and Aspergillus section Fumigati coinfection in an immunocompetent patient treated with corticosteroids.

BACKGROUND: Patients with severe viral pneumonia are likely to receive high-dose immunomodulatory drugs to prevent clinical worsening. Aspergillus species have been described as frequent secondary pneumonia agents in severely ill influenza patients receiving steroids. COVID-19 patients admitted to Intensive Care Unit (ICU) are receiving steroids as part of their treatment and they share clinical characteristics with other patients with severe viral pneumonias. COVID-19 patients receiving steroids should be considered a putative risk group of invasive aspergillosis. CASE REPORT: We are reporting a SARS-CoV-2/Aspergillus section Fumigati coinfection in an elderly intubated patient with a history of pulmonary embolism treated with corticosteroids. The diagnosis was made following the ad hoc definitions described for patients admitted to ICU with severe influenza, including clinical criteria (fever for 3 days refractory to the appropriate antibiotic therapy, dyspnea, pleural friction rub, worsening of respiratory status despite antibiotic therapy and need of ventilator support), a radiological criterion (pulmonary infiltrate) and a mycological criterion (several positive galactomannan tests on serum with ratio ≥0.5). In addition, Aspergillus section Fumigati DNA was found in serum and blood samples. These tests were positive 4 weeks after the patient was admitted to the ICU. The patient received voriconazole and after two month in ICU his respiratory status improved; he was discharged after 6 weeks of antifungal treatment. CONCLUSIONS: Severely ill COVID-19 patients would be considered a new aspergillosis risk group. Galactomannan and Aspergillus DNA detection would be useful methods for Aspergillus infection diagnosis as they allow avoiding the biosafety issues related to these patients.

COVID-19-Associated Invasive Aspergillosis: Data from the UK National Mycology Reference Laboratory.

COVID-19-associated pulmonary aspergillosis (CAPA) was recently reported as a potential infective complication affecting critically ill patients with acute respiratory distress syndrome following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, with incidence rates varying from 8 to 33% depending on the study. However, definitive diagnosis of CAPA is challenging. Standardized diagnostic algorithms and definitions are lacking, clinicians are reticent to perform aerosol-generating bronchoalveolar lavages for galactomannan testing and microscopic and cultural examination, and questions surround the diagnostic sensitivity of different serum biomarkers. Between 11 March and 14 July 2020, the UK National Mycology Reference Laboratory received 1,267 serum and respiratory samples from 719 critically ill UK patients with COVID-19 and suspected pulmonary aspergillosis. The laboratory also received 46 isolates of Aspergillus fumigatus from COVID-19 patients (including three that exhibited environmental triazole resistance). Diagnostic tests performed included 1,000 (1-3)-ß-d-glucan and 516 galactomannan tests on serum samples. The results of this extensive testing are presented here. For a subset of 61 patients, respiratory specimens (bronchoalveolar lavage specimens, tracheal aspirates, and sputum samples) in addition to serum samples were submitted and subjected to galactomannan testing, Aspergillus-specific PCR, and microscopy and culture. The incidence of probable/proven and possible CAPA in this subset of patients was approximately 5% and 15%, respectively. Overall, our results highlight the challenges in biomarker-driven diagnosis of CAPA, especially when only limited clinical samples are available for testing, and the importance of a multimodal diagnostic approach involving regular and repeat testing of both serum and respiratory samples.

Putative invasive pulmonary aspergillosis in critically ill patients with COVID-19: An observational study from New York City.

BACKGROUND: Critically ill patients with coronavirus disease-2019 (COVID-19) are at the theoretical risk of invasive pulmonary aspergillosis (IPA) due to known risk factors. PATIENTS/METHODS: We aimed to describe the clinical features of COVID-19-associated pulmonary aspergillosis at a single centre in New York City. We performed a retrospective chart review of all patients with COVID-19 with Aspergillus isolated from respiratory cultures. RESULTS: A total of seven patients with COVID-19 who had one or more positive respiratory cultures for Aspergillus fumigatus were identified, all of whom were mechanically ventilated in the ICU. Four patients were classified as putative IPA. The median age was 79 years, and all patients were male. The patients had been mechanically ventilated for a mean of 6.8 days (range: 1-14 days) before Aspergillus isolation. Serum galactomannan level was positive for only one patient. The majority of our cases received much higher doses of glucocorticoids than the dosage with a proven mortality benefit. All four patients died. CONCLUSIONS: Vigilance for secondary fungal infections will be needed to reduce adverse outcomes in critically ill patients with COVID-19.