Candida auris, colonization/screening
2019 Case Definition

Background

Candida auris (C. auris) is an emerging multidrug-resistant yeast that can cause invasive infections and is associated with high mortality. Some strains of C. auris are resistant to the three major classes of antifungals, severely limiting treatment options. C. auris can spread in healthcare settings and cause outbreaks. C. auris can colonize patients’ skin and other body sites, perhaps indefinitely, and colonization poses a risk both for invasive infection and transmission. C. auris persists in the healthcare environment for weeks, and certain routinely used disinfectants in healthcare settings are not effective against the organism. Recent investigations have demonstrated that one-third to half of all patients on a given unit, especially in a long-term care setting, can become colonized with C. auris within weeks of an index patient entering the facility. Outbreaks of C. auris in many parts of the world have been very difficult to control, sometimes requiring closure of hospital units and intensive public health interventions. In some countries with unchecked transmission of C. auris, it has become a leading cause of Candida infections, signaling a rapid change in the epidemiology of Candida infections.

In the United States, C. auris has been predominantly identified among patients with extensive exposure to ventilator units at skilled nursing facilities and long-term acute care hospitals, and those who have received healthcare in countries with extensive C. auris transmission. Other risk factors for C. auris infection are similar to those for invasive infection with other Candida species and include central venous catheter use, and recent broad-spectrum antibiotic or antifungal use.

Commonly used yeast identification methods often misidentify C. auris as other yeasts (especially Candida haemulonii) (Appendix 1 contains a list of fungal species commonly reported in place of C. auris by different laboratory identification methods). C. auris should be suspected when C. haemulonii (especially when isolated from an invasive site) or other organisms listed in Appendix 1 are identified by a yeast identification method that cannot accurately identify C. auris.

As of April 2018, over 700 patients with C. auris infection or colonization have been identified in the United States. Most cases have occurred in New York City, New Jersey, and the Chicago area. C. auris has only recently emerged in the United States, with cases primarily occurring after mid-2015. Given the recent emergence and limited geographic extent of cases, there is an opportunity to control the spread of C. auris before it becomes more widespread in the United States.

Control requires timely detection of the organism and adherence to recommended infection control practices, which includes proper hand hygiene, contact precautions, thorough environmental disinfection, contact tracing, and public health notification and action to prevent transmission within a healthcare facility and in the region.

Laboratory Criteria For Diagnosis

Confirmatory laboratory evidence:

Detection of C. auris from any body site using either culture or a culture independent diagnostic test (CIDT) (e.g., Polymerase Chain Reaction [PCR]).

Presumptive laboratory evidence:

Detection of C. haemulonii from any body site using a yeast identification method that is not able to detect C. auris (see CSTE position statement 18-ID-05, Appendix 1), AND
either the isolate/specimen is not available for further testing, or the isolate/specimen has not yet undergone further testing.

(Note: When additional test results are available, case re-classification may occur, including making this a non-case.)

Epidemiologic Linkage

Person resided within the same household with another person with confirmatory or presumptive laboratory evidence of C. auris infection or colonization.

OR

Person received care within the same healthcare facility as another person with confirmatory or presumptive laboratory evidence of C. auris infection or colonization.*

OR

Person received care in a healthcare facility that commonly shares patients with another facility that had a patient with confirmatory or presumptive laboratory evidence of C. auris infection or colonization.*

OR

Person had an overnight stay in a healthcare facility in the previous one year in a foreign country with documented C. auris transmission (https://www.cdc.gov/fungal/candida-auris/tracking-c-auris.html).

*Note: the person with confirmatory or presumptive laboratory evidence of C. auris and potentially exposed individuals do not need to be present in a health care facility for any overlapping time period. Any case occurring in a facility with a confirmed or probable case identified in the prior 12 months would be considered epidemiologically linked.

Criteria to Distinguish a New Case from an Existing Case

• A person with a clinical case should not be counted as a colonization/screening case
  thereafter (e.g., patient with known infection who later has colonization of skin is not
  counted as more than one case).
• A person with a colonization/screening case can be later categorized as a clinical case
  (e.g., patient with positive screening swab who later develops bloodstream infection would
  be counted in both categories).

Comments

Candida auris, clinical: Public Health jurisdiction may consider stratifying clinical cases as invasive vs non-invasive.

Suspected

Person with presumptive laboratory evidence from a clinical specimen collected for the purpose of diagnosing or treating disease in the normal course of care and no evidence of epidemiologic linkage. A clinical specimen includes specimens from sites reflecting invasive infection (e.g., blood, cerebrospinal fluid) and specimens from non-invasive sites such as wounds, urine, and the respiratory tract, where presence of C. auris may simply represent colonization and not true infection.

Probable

Person with presumptive laboratory evidence from a clinical specimen collected for the purpose of diagnosing or treating disease in the normal course of care and evidence of epidemiologic linkage. A clinical specimen includes specimens from sites reflecting invasive infection (e.g., blood, cerebrospinal fluid) and specimens from non-invasive sites such as wounds, urine, and the respiratory tract, where presence of C. auris may simply represent colonization and not true infection.

Confirmed

Person with confirmatory laboratory evidence from a clinical specimen collected for the purpose of diagnosing or treating disease in the normal course of care. This includes specimens from sites reflecting invasive infection (e.g., blood, cerebrospinal fluid) and specimens from non-invasive sites such as wounds, urine, and the respiratory tract, where presence of C. auris may simply represent colonization and not true infection.