ATLANTA – The persistence and transmission of Candida auris in health care settings appears to be dependent on environmental survival, underscoring the need for careful investigation of the environment – and, in particular, multiuse patient equipment.
That’s the key lesson from one of the largest outbreaks of the emerging, multidrug-resistant pathogen to date, David Eyre, DPhil, said at the Internationalon Emerging Infectious Diseases.
“Our experience at Oxford began with a Public Health England alert, which closely followed a similar alert from the [Centers for Disease Control and Prevention] in the summer of 2016,” Dr. Eyre of the University of Oxford (England) said during an update on the epidemiology of the outbreak and the successful, multipronged effort to control it.
The outbreak, which occurred in the neurosciences intensive care unit of Oxford University Hospitals beginning in early 2015, was detected in 2016 when a cluster of C. auris infections was identified and traced to the unit. An intensive patient and environmental screening program was established, isolation protocols were used for patients who tested positive, enhanced cleaning processes were initiated, and equipment was removed and replaced with single-use equipment when possible.
“We also worked quite closely with our staff to raise awareness,” he said, adding that colonized patients who were undergoing a surgical procedure received single-dose antifungal prophylaxis prior to the procedure.
A case-control study was conducted, and after the researchers used multivariate logistic regression to control for length of stay, patient physiology, and biomarkers, exposure to multiuse skin surface axillary temperature monitoring was shown to be one of the strongest independent predictors of C. auris colonization and infection (odds ratio 6.80), he said, adding that antifungal exposure was also a significant risk factor, but only 5% of patients had received antifungals.
The axillary probes were then removed from the environment. As of April 2017 (when the probes were removed), 66 patients had been colonized or infected, and an additional 10 cases occurred after the probes were removed, with the last case occurring in November 2017.
Seven of the 76 cases involved invasive infection, and 1 patient died several months after hospital discharge, Dr. Eyre said.
The patient screening processes allowed for estimation of colonization time (approximately 2 months), and also allowed for whole-genome sequencing of 79 samples from 43 patients, 6 environmental isolates, and 2 isolates from regional surveillance, Dr. Eyre said.
All outbreak sequences formed a single genetic cluster within the C. auris South African clade, and were found to have been introduced to Oxford around 2012 or 2013, with about six mutations per year, or “roughly 12 million base pairs in total,” he said, adding that both patients and temperature probes were colonized with multiple strains, and there was “close mixing” between the two.
This pattern changed following removal of the temperature probes, but it took some time.
“However, from November  onward – so that’s now 291 days … we’ve not had another new patient isolate, and that’s not only no invasive infection, but also no colonization despite continuing the screening program,” he said.
According to the, C. auris is “an emerging fungus that presents a serious global health threat” because of its often multidrug-resistant nature, difficulty identifying the pathogen using standard laboratory methods, and the risk for misidentification in labs without specific technology, which could lead to inappropriate management.
“It has caused outbreaks in health care settings. For this reason, it is important to quickly identify C. auris in a hospitalized patient so that health care facilities can take special precautions to stop its spread,” a CDC page on C. auris states. “CDC encourages all U.S. laboratory staff who identify C. auris to notify their state or local public health authorities and CDC at.”
Dr. Eyre reported having no disclosures.
SOURCE: Eyre D et al. ICEID 2018 Oral Presentation.
© Frontline Medical Communications 2018-2021. Reprinted with permission, all rights reserved.