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Difficulty: Very hardInfection Control and Hospital-Acquired Conditions

A 70-year-old man is transferred to the medical intensive care unit (MICU) from a long-term acute care hospital for management of acute respiratory failure. On admission, a routine axilla and groin screening swab returns positive for *Candida auris*. The patient is appropriately placed on Contact Precautions. Two weeks later, an outbreak investigation is initiated when three other patients in the same MICU develop *C. auris* candidemia. An infection control audit reveals the following:

- 100% staff compliance with hand hygiene before and after patient contact using alcohol-based hand sanitizers.
- Staff correctly don and doff gowns and gloves prior to entering and exiting patient rooms.
- Dedicated, disposable medical equipment (e.g., stethoscopes, blood pressure cuffs) is used for each patient.
- Environmental services perform daily and terminal cleaning of patient rooms using a standard quaternary ammonium disinfectant.
- No prophylactic antimicrobial or antifungal agents are administered to asymptomatic patients.

Based on current infection control guidelines, which of the following is the most likely root cause of this pathogen's transmission within the unit?

  1. A
    Inappropriate use of alcohol-based hand sanitizers instead of soap and water
  2. B
    Droplet transmission due to the lack of airborne infection isolation rooms
  3. Environmental persistence due to the use of an ineffective chemical disinfectantAnswer
  4. D
    Unrecognized colonization due to the omission of active surveillance blood cultures
  5. E
    Cross-transmission driven by the absence of systemic antifungal prophylaxis in exposed patients

Answer

The most likely root cause is environmental persistence due to the use of an ineffective chemical disinfectant.
The correct answer is environmental persistence due to the use of an ineffective chemical disinfectant. *Candida auris* is an emerging, multidrug-resistant yeast that causes invasive healthcare-associated infections with high mortality. Unlike most other *Candida* species, *C. auris* readily colonizes the skin and sheds heavily into the healthcare environment, where it can survive on surfaces for weeks. A critical component of *C. auris* infection control is targeted environmental cleaning. Standard quaternary ammonium compounds, which are commonly used for routine hospital disinfection (e.g., for MRSA or VRE), are frequently ineffective against *C. auris*. The Centers for Disease Control and Prevention (CDC) strictly recommends using an EPA-registered hospital-grade disinfectant specifically effective against *C. auris* (List P) or, if unavailable, a sporicidal agent effective against *C. difficile* (List K), such as sodium hypochlorite (bleach) or hydrogen peroxide. The use of a standard quaternary ammonium disinfectant in this scenario allowed the pathogen to persist on surfaces, serving as an ongoing reservoir for cross-transmission despite perfect compliance with personal protective equipment and hand hygiene.

Step-by-Step Solution

1
Analyze the transmission characteristics of the identified pathogen.
Candida auris is identified as a highly resilient fungus that vigorously colonizes human skin and heavily contaminates the patient environment, persisting on surfaces for weeks.
Understanding the pathogen's specific mode of transmission is essential to evaluate the effectiveness of the current infection control bundle.
2
Evaluate the hand hygiene practices reported in the audit.
The staff uses alcohol-based hand sanitizers with 100% compliance. This is the correct, guideline-supported hand hygiene method for C. auris.
Alcohol-based sanitizers effectively kill C. auris, differentiating its management from spore-forming pathogens like C. difficile.
3
Evaluate the environmental cleaning practices reported in the audit.
The facility uses a standard quaternary ammonium disinfectant. This is inadequate for C. auris, which requires EPA List P disinfectants or sporicidal agents (like bleach or hydrogen peroxide).
Quaternary ammonium compounds fail to eradicate C. auris from the environment, allowing continuous fomite-driven cross-transmission despite perfect staff adherence to gowns, gloves, and hand hygiene.

Key Concept

Standard quaternary ammonium disinfectants are ineffective against Candida auris; environmental cleaning for this pathogen requires an EPA-registered hospital-grade disinfectant specifically active against C. auris or a sporicidal agent.
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Topics

Infection Control and Hospital-Acquired Conditions

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