Experimental Drug May Combat Drug-Resistant Fungus

Drug-resistant Candida auris observed to be particularly susceptible to investigational drug.

Candida auris is a fungus that can cause life-threatening infections, and has been known to live in hospitals. This fungus has been found to be resistant to multiple classes of antimicrobials, which severely limits treatment options.

Since it was first reported in 2009, the drug-resistant fungus was linked to infections in 9 countries, and has caused 2 known hospital outbreaks.

In a study published by Antimicrobial Agents and Chemotherapy, the authors examined C. auris’ resistance and growth patterns, and found that an investigational drug, SCY-078, could treat the infections.

“This emerging fungal species has started to infect patients globally, causing invasive infections that are associated with a high death rate,” said lead researcher Mahmoud Ghannoum, PhD. “It is multidrug-resistant, and some strains isolated from patients are resistant to all commercially available antifungal drugs. Multi-drug-resistance used to be reported for bacteria only, and now we must add fungi to the list.”

The investigators collected and analyzed 16 strains of the fungus from patients in Germany, Japan, Korea, and India. The strains were treated with a battery of 11 drugs that belonged to different classes of antifungals to determine concentrations able to kill C. auris.

Although a majority of the samples were resistant to the drugs, small amounts of SCY-078 were observed to distort the fungus and impair its growth, according to the study. The authors said that these findings are an important step to further developing the drug to treat C. auris infections.

When exposed to SCY-078, the fungi was unable to divide, which suggests the drug could stop infections and limit its spread.

Developing new drugs against C. auris is important, because it is known to live on catheters in intensive care units, and form highly drug-resistant communities, called biofilms. The authors exposed the fungi to silicone surfaces similar to catheters, and discovered that the biofilms were weakened after exposure to SYC-078.

While the findings depended on the strain, it suggests that the drug would be particularly effective in treating catheter-associated infections, according to the study.

Previously, the investigational drug has demonstrated efficacy against Candida strains that cause catheter-associated infections, such as C. albicans and C. tropicalis.

“This drug is especially promising because of its broad anti-Candida activity, including activity against drug-susceptible and resistant strains,” Dr Ghannoum said.

This study is the first to show C. auris does not germinate and create spores as other fungi do, which the authors said is surprising due to its ability to spread quickly. Additionally, only certain strains create enzymes that help the fungi establish infections, according to the study. However, despite these perceived weaknesses, C. auris is able to become highly-drug resistant and infect patients.

These findings support clinical trials to evaluate the efficacy and safety of SYC-078, and may eventually lead to novel treatment options.

“Understanding the virulence of C. auris and showing that the investigational drug is effective may lead to the development of new medications to combat this emerging health threat,” Dr Ghannoum concluded.