Mucormycosis resistance
After CAPA, candidiasis and COVID-19-associated mucormycosis (CAM) – most frequently, rhino-orbital-cerebral disease or pulmonary disease – have been the leading reported fungal coinfections in COVID-19, said Dr. Hoenigl, who described the incidence, timeline, risk factors, and pathogenesis of these infections in a review published this year in Nature Microbiology. .
In India, where there has long been high exposure to Mucorales spores and a greater burden of invasive fungal disease, the rate of mucormycosis doubled in 2021, with rhino-orbital-cerebral disease reported almost exclusively, he said. Pulmonary disease has occurred almost exclusively in the ICU setting and has been present in about 50% of cases outside of India, including Europe and the United States.
A preprint meta-analysis of CAM cases posted by the Lancet in July 2022, in which investigators analyzed individual data of 556 reported cases of COVID-19–associated CAM, shows diabetes and history of corticosteroid use present in most patients, and an overall mortality rate of 44.4%, most of which stems from cases of pulmonary or disseminated disease. Thirteen of the 556 reported cases were from the United States.
An important take-away from the analysis, Dr. Hoenigl said, is that Aspergillus coinfection was seen in 7% of patients and was associated with higher mortality. “It’s important to consider that coinfections [of Aspergillus and Mucorales] can exist,” Dr. Hoenigl said, noting that like CAPA, pulmonary CAM is likely underdiagnosed and underreported.
As with CAPA, the clinical and radiological features of pulmonary CAM largely overlap with those associated with COVID-19, and bronchoscopy plays a central role in definitive diagnosis. In the United States, a Mucorales PCR test for blood and BAL fluid is commercially available and used at some centers, Dr. Hoenigl said.
“Mucormycosis is always difficult to treat ... a lot of the treatments don’t work particularly well,” said Dr. Thompson. “With aspergillosis, we have better treatment options.”
Dr. Thompson worries, however, about treatment resistance becoming widespread. Resistance to azole antifungal agents “is already pretty widespread in northern Europe, particularly in the Netherlands and part of the U.K.” because of injudicious use of antifungals in agriculture, he said. “We’ve started to see a few cases [of azole-resistant aspergillosis in the United States] and know it will be more widespread soon.”
Treatment resistance is a focus of the new WHO fungal priority pathogens list – the first such report from the organization. Of the 19 fungi on the list, 4 were ranked as critical: Cryptococcus neoformans, Candida auris, Aspergillus fumigatus, and Candida albicans. Like Dr. Thompson, Dr. Hoenigl contributed to the WHO report.
Dr. Hoenigl reported grant/research support from Astellas, Merck, F2G, Gilread, Pfizer, and Scynexis. Dr. Marr disclosed employment and equity in Pearl Diagnostics and Sfunga Therapeutics. Dr. Thompson, Dr. Permpalung, and Dr. Zeki reported that they have no relevant financial disclosures.