Survival, Persistence, and Isolation of the Emerging Multidrug-Resistant Pathogenic Yeast Candida auris on a Plastic Health Care Surface

Abstract

The emerging multidrug-resistant pathogenic yeast Candida auris represents a serious threat to global health. Unlike most other Candida species, this organism appears to be commonly transmitted within health care facilities and causes health care-associated outbreaks. To better understand the epidemiology of this emerging pathogen, we investigated the ability of C. auris to persist on plastic surfaces common in health care settings compared with that of Candida parapsilosis, a species known to colonize the skin and plastics. Specifically, we compiled comparative and quantitative data essential to understanding the vehicles of spread and the ability of both species to survive and persist on plastic surfaces under controlled conditions (25°C and 57% relative humidity), such as those found in health care settings. When a test suspension of 10⁴ cells was applied and dried on plastic surfaces, C. auris remained viable for at least 14 days and C. parapsilosis for at least 28 days, as measured by CFU. However, survival measured by esterase activity was higher for C. auris than C. parapsilosis throughout the 28-day study. Given the notable length of time Candida species survive and persist outside their host, we developed methods to more effectively culture C. auris from patients and their environment. Using our enrichment protocol, public health laboratories and researchers can now readily isolate C. auris from complex microbial communities (such as patient skin, nasopharynx, and stool) as well as environmental biofilms, in order to better understand and prevent C. auris colonization and transmission.

Keywords: Candida; Candida auris; Candida parapsilosis; clinical methods; persistence; public health.

FIG 1

The log transformed recovery of viable C. auris (blue) and C. parapsilosis (gray) at each time point as determined by culture. The middle bar within each box represents the median; the top and bottom of the box represent the 75th and 25th quartiles, respectively, and dark circles represent outliers. A single asterisk indicates P < 0.05 and double asterisk indicates P < 0.001 between C. auris and C. parapsilosis for each time point.

FIG 2

The log transformed recovery of viable C. auris (blue) and C. parapsilosis (gray) at each time point as determined by esterase activity. The middle bar within each box represents the median; the top and bottom of the box represent the 75th and 25th quartiles, respectively, and dark circles represent outliers. A single asterisk indicates P < 0.05 and double asterisk indicates P < 0.001 between C. auris and C. parapsilosis for each time point.

FIG 3

Isolation of C. auris from clinical and environmental specimens (n = 77) by direct plating on CHROMagar Candida (blue bars) and by processing through the Salt SAB Dex enrichment broth procedure (red bars).