The COVID-19 conditions in Brazil have opened the door for the emergence and spread of a relatively new fungus that is quickly showing signs of becoming a drug-resistant “super fungus”, according to a new report published in the Mushroom Journal.
Since December 2020, researchers have detected Candida auris in nine patients in a hospital in Salvador, northeastern Brazil.
Typically, mushrooms of the genus Candidiasis are relatively harmless, most commonly causing treatable vaginal yeast infections and oral thrush. However, with a death rate of almost 60%, C. auris looks different and SARS-CoV-2 patients are ideal targets.
C. auris can enter the bloodstream, causing a systemic infection known as candidemia, which is similar to bacterial sepsis. The invasion of the bloodstream and the exacerbated immune system response to the pathogen can then damage multiple organs, ultimately leading to death.
“The species is not very sensitive to disinfectants used by hospitals and clinics,” said Arnaldo Colombo, lead author of the new study and director of the Special Mycology Laboratory at the Federal University of São Paulo (UNIFESP). . “As a result, it is able to persist in hospitals, where it colonizes health workers and ends up infecting patients with severe COVID-19 and other long-term critical patients.”
Of the nine patients at the hospital, Colombo said some had the colonized fungus, while others were infected and symptomatic.
“We are monitoring the evolving characteristics of C. auris isolates from patients at the Salvador hospital, and we have already found samples with reduced sensitivity to fluconazole and echinocandins. These belong to the main class of drugs used to treat invasive candidiasis, ”Colombo said.
In fact, Colombo and his team have tested hospital samples for susceptibility to antifungal drugs every month since December 2020. In recent samples, researchers have had to assay the culture with 4 to 5 times the amount of the drug to inactivate it by compared to samples from last year and even the start of this year.
“The mechanism that allows the species to develop drug resistance is not enzymatic degradation, as in so many antibiotic resistant bacteria,” Colombo said. “The fungus develops structural changes in the proteins to which the drug binds to inhibit cell wall synthesis, which is key to its survival.
The Colombo group at UNIFESP is currently working with Dutch colleagues to genetically sequence fungi to see if the gene that confers drug resistance to C. auris transferred from December 2020 to now.
C. auris was first isolated in Japan in 2009, in Asia and Europe in 2011, in the Americas, Colombia, Panama and Chile in 2016, and finally in Brazil in 2020. So far, 5 clades, or lines, of the fungus have been described.
According to Colombo, the clade isolated in Salvador looks more like the Asian original than the variant detected in Venezuela and other South American countries, suggesting a second independent arrival of the super fungus on the continent.
“Alternatively, there may be a local environmental source, as none of the Brazilian patients infected with the fungus have traveled abroad or had infected relatives,” Colombo said.
Whatever its origin, the research team is particularly concerned about the super fungus as Brazil experiences a second wave of COVID-19 infections.
“In the near future, overcrowding and limited resources for infection control practices, such as prolonged use of personal protective equipment due to shortages, will be fertile ground for C. auris spread, colonize invasive devices and deflagrate nosocomial infections, ”the team concludes.