CDC found 6.9% of those testing positive for Candida auris colonization on skin develop invasive infection, and calls for better surveillance and prevention.
Candida auris
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Invasive infection with Candida auris developed in 6.9% of patients who tested positive for colonization on the skin, according to an analysis1 of US national case-based surveillance data by the Centers for Disease Control and Prevention (CDC).
The study analyzed data from 21,195 patients with positive screening results from 36 reporting jurisdictions between 2016 and 2023. Infection had developed in 6.9% (1,458 across 22 jurisdiction); and among those, 40.1% (584) evidenced a positive clinical culture from blood and 26.8% (391) from urine.
"This study highlights the potential for C auris infections, particularly candidemia, among colonized patients and the importance of timely identification and management," lead author Anna Baker, MPH, Epidemiologist, Mycotic Diseases Branch, CDC, Atlanta, GA, told Contagion.
"Our findings show that C auris can be detected through screening long before it may be detected through clinical specimens, emphasizing the benefit of screening to facilitating earlier interventions and reducing opportunities for transmission," she said.
The investigators found that the number of patients with positive screens increased each year of the study period, and that the percentages of those developing an invasive infection increased from0.0% (0/13) in 2016 to 9.9% (129,1299) in 2020, before decreasing to 4.9% (365/7/493) in 2023. They attributed the decline after 2020, in part, to improved infection prevention and control efforts, as well as increased screening after COVID-19.
The median number of days from initial screening to detecting a clinical specimen was longest for blood (58, IQR 22-130) and shortest for respiratory (28, IQR 17-74). Positive testing in blood was approximately twice as common as urine in women; with similar occurrence from blood and urine in men.
"Results showing a greater proportion of positive urine specimens among men compared to women might reflect patterns in medical device usage—eg, urinary catheters—anatomical susceptibility, or diagnostic practices," Baker posited.
The rate of infections following positive screening was similar by age and sex, but varied by region and facility type. Positive samples representing invasive infection were most frequently collected in long-term acute-care hospitals, followed by acute care hospitals, ventilator-capable skilled nursing facilities (SNFs), non-ventilator-equipped SNFs, and then other facility types.
6.9% of patients colonized with C auris developed invasive infections, with bloodstream infections being the most common.
Screening often detects C auris weeks before clinical infection, allowing for earlier intervention and reduced transmission risk.
Infection rates varied by facility type and region, with long-term acute care hospitals seeing the highest rates and regional differences likely tied to testing and reporting practices.
Although the volume of screening and frequency of clinical cases was highest in the West, the investigators note that this region also had a relatively low percentage of clinical cases involving blood. "That finding might reflect regional differences in case reporting and in testing practices for C auris in noninvasive body sites," they suggested.
Baker and colleagues suspect that their data underestimates the actual percentage of patients with C auris colonization who progress to infection. The factors underlying that possible underestimation include: screening omissions; insensitivity of culture; treating clinical laboratories that do not routinely distinguish C auris from other Candida species. In addition, they note that data from 2024 were not finalized at the time the study was submitted for publication, and suggest that some patients at the end of the study period might not have had sufficient lead time for clinical cases to occur.
The investigators acknowledged other limitations of the study, including inadequate data on previous negative screening results, on differentiating between infection and colonization, as well as on underlying patient conditions.
"Rigorous infection prevention and control remain necessary to prevent the spread of C auris and subsequent clinical infections," Baker and colleagues urge."Further studies could investigate risk factors and strategies to prevent invasive C auris infections through patients with colonization--eg, through patient decolonization."
In discussing the study with Contagion, Baker pointed out that while it did not directly evaluate decolonization protocols, it does demonstrate that patients are persistently colonized and presents this challenge for facilities caring for these patients, and evidences the potential benefit of strategies to reduce C auris skin burden to prevent transmission.
"Currently there are no recommended decolonization strategies for C auris. The CDC, along with other agencies, are interested in exploring pathogen reduction or 'decolonization' methods as an additional tool to mitigate transmission and prevent additional cases, but C auris presents many challenges because of its high resistance and its persistence on skin and surfaces," Baker explained.
"Established clinical endpoints are needed to evaluate products' abilities to not only reduce C auris burden but also reduce infections and transmission," she said.
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