#16,077
Just over 5 years ago (June 24th, 2016) the CDC issued a Clinical Alert to U.S. Healthcare facilities about the Global Emergence of Invasive Infections Caused by the Multidrug-Resistant Yeast Candida auris.
C. auris is an emerging fungal pathogen that was first isolated in Japan in 2009. It was initially found in the discharge from a patient's external ear (hence the name `auris'). Retrospective analysis has traced this fungal infection back over 25 years.A week later we saw a release from the UK's PHE On The Emergence Of Candida auris In The UK, where they detailed a large (and ongoing since April 2015) nosocomial outbreak at an adult critical care unit in England.
While they've taken a bit of a backseat due to the pandemic, we've covered the spread, and evolution, of C. auris and other MDROs (Multidrug-Resistant Organisms) - such as C. difficle, CRE, HvKp and MRSA - often in this blog, because together they pose a long-term threat to public health that could rival any influenza pandemic.
ECDC Risk Assessment: Emergence of Hypervirulent Klebsiella pneumoniae ST23 Carrying Carbapenemase genes in EU/EEA countries
EID Journal: COVID-19 and Fatal Sepsis Caused by Hypervirulent Klebsiella pneumoniae, Japan, 2020
COCA Call:Preventing the Spread Multidrug-resistant Organisms (MDROs) in Nursing Homes
mBio: On the Emergence of Candida auris: Climate Change, Azoles, Swamps, and Birds
Although most MDRO infections are still treatable - AMR (antimicrobial resistance) isn't some obscure future threat - as it already impacts millions of lives each year around the globe. In 2019, the CDC estimated that: More than 2.8 million antibiotic-resistant infections occur in the United States each year, and more than 35,000 people die as a result.
Each year we draw a little closer to a long-predicted, but highly plausible `post-antibiotic era', where even common infections become resistant to most antibiotics, and something as simple as a scraped knee, or elective surgery, could be deadly.
C. auris was made nationally notifiable in 2018, and while the absolute numbers remain low, this MDRO is of particular concern because:
- C. auris infections have a high fatality rate
- The strain appears to be resistant to multiple classes of anti-fungals
- This strain is unusually persistent on fomites in healthcare environments.
- And it can be difficult for labs to differentiate it from other Candida strains
While pan-resistant C. auris has been reported on rare occasions, it has always been associated with patients who had already received, or were receiving, anti-fungal treatments.
These two unrelated clusters, both reported since January 2021, suggest the transmission of pan - and echinocandin-resistant strains for the first time in the United States. Due to the limits of testing and surveillance, these 5 cases likely only represent the tip of this emerging pan-resistant iceberg.
It is worth noting that people can be colonized with C. auris, without becoming clinically infected, and that some of these detected cases were only colonized.
However, those who are colonized are at risk of future infection, and can easily spread the fungus to other people - or to environmental surfaces - where it is difficult to remove and can go on to infect others.
I've reproduced the text of yesterday's MMWR report below, but follow the link for the full report, including references.Notes from the Field: Transmission of Pan-Resistant and Echinocandin-Resistant Candida auris in Health Care Facilities ― Texas and the District of Columbia, January–April 2021
Weekly / July 23, 2021 / 70(29);1022–1023
Meghan Lyman, MD1; Kaitlin Forsberg, MPH1; Jacqueline Reuben, MHS2; Thi Dang, MPH3; Rebecca Free, MD1; Emma E. Seagle, MPH1; D. Joseph Sexton, PhD1; Elizabeth Soda, MD4; Heather Jones, DNP4; Daryl Hawkins, MSN2; Adonna Anderson, MSN2; Julie Bassett, MPH3; Shawn R. Lockhart, PhD1; Enyinnaya Merengwa, MD, DrPH3; Preetha Iyengar, MD2; Brendan R. Jackson, MD1; Tom Chiller, MD1 (View author affiliations)View suggested citation
Candida auris is an emerging, often multidrug-resistant yeast that is highly transmissible, resulting in health care–associated outbreaks, especially in long-term care facilities. Skin colonization with C. auris allows spread and leads to invasive infections, including bloodstream infections, in 5%–10% of colonized patients (1). Three major classes of antifungal medications exist for treating invasive infections: azoles (e.g., fluconazole), polyenes (e.g., amphotericin B), and echinocandins. Approximately 85% of C. auris isolates in the United States are resistant to azoles, 33% to amphotericin B, and 1% to echinocandins (2), based on tentative susceptibility breakpoints.* Echinocandins are thus critical for treatment of C. auris infections and are recommended as first-line therapy for most invasive Candida infections (3). Echinocandin resistance is a concerning clinical and public health threat, particularly when coupled with resistance to azole and amphotericin B (pan-resistance).
Pan-resistant C. auris isolates have been reported previously, although rarely, from the United States (4) and other countries (5). Three pan-resistant C. auris cases reported in New York developed resistance following echinocandin treatment and lacked epidemiologic links or common health care (4), suggesting that resistance resulted from antifungal pressure rather than via person-to-person transmission. Since January 2021, however, the Antibiotic Resistance Laboratory Network has detected independent clusters of pan-resistant or echinocandin-resistant cases in Texas and the District of Columbia (DC). Each cluster involved common health care encounters and no known previous echinocandin exposure, suggesting transmission of pan- and echinocandin-resistant strains for the first time in the United States.
Among 101 clinical and screening cases of C. auris† in DC during January–April 2021, three had an isolate that was pan-resistant. All resistant isolates were identified through skin colonization screening at one long-term care facility for severely ill patients, including those requiring mechanical ventilation.
Among 22 clinical and screening cases of C. auris in Texas during the same period, two were pan-resistant and five were resistant to both echinocandins and fluconazole. These seven cases were identified in patients who were cared for at two facilities that share patients in the same city; two patients were at a long-term acute care hospital, three at a short-term acute care hospital, and two at both facilities. Among these cases, four were identified through colonization screening and three through clinical isolates (two blood isolates and one wound isolate).
No known epidemiologic links were identified between the Texas and DC clusters. No patients with pan- or echinocandin-resistant isolates in either cluster had received echinocandins before C. auris specimen collection. Thirty-day mortality in both outbreaks combined was 30%, but the relative contribution of C. auris was unclear.
These two simultaneous, independent clusters of pan- or echinocandin-resistant C. auris cases in patients with overlapping inpatient health care exposures and without previous echinocandin use provide the first evidence suggesting that pan- or echinocandin-resistant C. auris strains might have been transmitted in U.S. health care settings.
Surveillance, public health reporting, and infection control measures are critical to containing further spread. Clinicians should consider early antifungal susceptibility testing in patients with C. auris infection, especially in those with treatment failure. Data are lacking about the most appropriate therapy for pan-resistant infections. Combination and investigational antifungal treatments can be considered, but evidence in clinical settings is limited (6). More information is needed to evaluate patient outcomes and identify proper treatment for C. auris cases with pan-resistance or echinocandin resistance.
Corresponding author: Meghan Lyman, yeo4@cdc.gov, 404-639-4241.
