In March 2023 the CDC commented on data published in the Annals of Internal Medicine that revealed an “alarming” spread of the emerging fungus Candida auris in healthcare facilities in 2020-2021. It also identified a “concerning” increase in 2021 of the number of cases that were resistant to the antifungal medicine echinocandins. In its statement, the CDC deemed the fungus an “urgent” antimicrobial resistant threat, particularly with its growing resistance to antifungal drugs and its potential to cause “severe infections with high death rates”.
What is Candida auris?
Candida auris (C. auris) is a type of yeast that has been causing “severe illness” in hospitalised patients in several countries. For some patients, it enters the bloodstream and causes serious invasive infections throughout the body. The CDC identifies three main causes of concern associated with the fungus:
- It is often “multidrug-resistant”.
- It is difficult to identify with “standard laboratory methods” and can be misidentified.
- It has caused outbreaks in healthcare settings.
Candida auris featured in WHO’s list of fungal priority pathogens last year in the “critical” class.
Although first identified in Japan in 2009, C. auris was first reported in 2016 in the US. Since then, a total of 3,270 clinical cases (where infection is present) and 7,413 screening cases (where the fungus is present but not causing infection) have been reported to the end of 2021. The most dramatic increase in cases occurred during 2020-2021. Dr Meghan Lyman, lead author of the paper that presents these results, called for continued efforts to identify and contain infections.
“The rapid rise and geographic spread of cases is concerning and emphasises the need for continued surveillance, expanded lab capacity, quicker diagnostic tests, and adherence to proven infection prevention and control.”
The CDC reports that patients in healthcare facilities who have been there a long time, have lines of tubes entering their body, or have previously received antibiotics or antifungal medications appear to be at “highest risk of infection”. The increase in cases is linked to both “poor general infection prevention and control (IPC) practices” but also “enhanced efforts to detect cases”.
“The timing of this increase and findings from public health investigations suggest C. auris spread may have worsened due to strain on healthcare and public health systems during the COVID-19 pandemic.”
Professor William Schaffner of the Vanderbilt University Medical Centre told Washington Post that once the fungi get into a hospital, they are “very difficult to control”.
“They can persist, smouldering, causing infections for a considerable period of time despite the best efforts of the infection control team and everyone else in the hospital.”
AMR and C. auris
A particularly concerning feature of these infections is the growing resistance to specific medications. The CDC offers reassurances that “most” of these infections are treatable with echinocandins. However, some infections have been resistant to “all three main classes of antifungal medications”. When this occurs, multiple classes of antifungals at “high doses” are required.
With increased media attention caused by the CDC’s warning, eyes are on vaccine developers to see if there are preventative measures that could be taken. On 23rd March 2023, The Lundquist Institute (TLI) announced that it has a vaccine candidate in development. This vaccine has reported been shown to “effectively treat mice” with the fungal infection, with the next step being human clinical trials.
“The vaccine used to immunise mice is composed of dual Candida cell surface antigens, which upon vaccination produce neutralising and immune enhancer antibodies. The vaccine also induces a robust T-cell immunity against the fungus, allowing mice to survive the infection.”
Furthermore, TLI suggests that in combination with antifungal drugs, the vaccine results in an “augmented survival”. Dr Ashraf Ibrahim, Investigator at TLI hopes the vaccine can be produced in “good quantities” for the next stage of clinical trials.
“We now have the capability to protect patients who infected by this deadly pathogen.”
We look forward to discussing the possibilities of AMR prevention at the World Vaccine Congress in Washington next week. Join us by getting your tickets here!