Unraveling a Candida auris Outbreak: Infection Control Challenges in a Burn ICU

Candida auris in the burn intensive care unit

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Candida auris (C auris) is an emerging fungal pathogen notorious for its extensive drug resistance, environmental persistence, and ability to cause severe infections in immunocompromised individuals. Burn patients, particularly those in intensive care units (ICUs), are at heightened risk due to prolonged hospital stays, open wounds, and frequent medical interventions.

A recent outbreak at a burn ICU (BICU) in Illinois provides a critical case study published in Emerging Infectious Disease Journal on how C auris spreads despite stringent infection control measures.

“In BICUs patients are at increased risk for health care-acquired infections because of breakdown of the skin barrier and the immunocompromising effects of burns; infection is the leading cause of death after burn injury. Fungal wound infections are reported in 6% [to] 45% of all burn admissions; candidemia develops in up to 5% of patients with severe burns. Unlike most Candida species, C auris has a tropism for skin, and it can readily colonize or infect adjacent large, open, nutrient-rich burn wounds.”

The authors continue on to say the patients “have frequent infections and large, open wounds, [and they] often require treatment with systemic and topical antimicrobials, both of which have capacity to eliminate competitive microbiota and encourage colonization with resistant organisms such as C auris. Care provided in BICUs, such as skin debridement, may disperse colonized or infected skin cells into the environment, which contributes to transmission.”

This study was completed in “The Burn Center, [which] is a 10-bed intensive care unit caring for pediatric and adult burn patients at a 547-bed academic tertiary care medical center in the Chicago metropolitan area, Illinois, USA.”

Furthermore, the unit accommodates overflow from other services' ICUs, including both medical and surgical care. The unit adheres to universal contact precautions (gowns, gloves, masks, and eye protection) for all patients, staff, and visitors. The researchers extracted patient data through a retrospective review of the hospital's electronic medical records.

The Challenges of Containing C auris

C auris is difficult to eliminate from health care settings due to its ability to colonize the skin and survive on surfaces for extended periods. In burn ICUs, where patients undergo frequent debridement and require systemic antimicrobials, the risk of colonization is even higher. Standard infection prevention strategies in this outbreak—including universal contact precautions, rigorous environmental cleaning, and enhanced personal protective equipment (PPE) compliance—were insufficient to prevent transmission.

“The outbreak investigation, led by the infection prevention team, consisted of admission screening and weekly point prevalence surveys of all patients in the unit. We defined a hospital-acquired case of C auris as any illness in a patient who, after a negative C auris admission screen, tested positive for C auris on subsequent weekly point prevalence screens or in any clinical specimen. We defined colonized cases as patients who had C auris identified from surveillance cultures but no detection of C auris in any clinical specimens. Clinical cultures refer to blood, wound, respiratory, or urine cultures.”

“We conducted epidemiologic investigations to identify commonalities between cases, including health care workers, medical equipment, prior room occupancies, and exposure locations outside of the BICU, including the operating room, tub room, and procedural areas such as the interventional radiology and gastroenterology suites. We reviewed patients’ history of C auris through query of the Illinois extensively drug-resistant organism registry.”

Compounding the issue, C auris often remains undetected in patients until routine screening or clinical cultures confirm its presence. In this outbreak, the first patient was diagnosed via blood culture in 2021, but additional cases continued to emerge over the next 21 months. Weekly point prevalence surveys revealed 22 additional cases, suggesting ongoing transmission despite containment efforts.

Environmental and Staff-Related Transmission Risks

Investigators identified multiple infection control breaches that may have facilitated the spread of C auris. Shared medical equipment—including Doppler devices, ultrasound machines, and forced-air patient warmers—was not consistently disinfected, increasing the risk of cross-contamination. Hand hygiene adherence, although relatively high among nursing staff, was significantly lower among patient transporters (32%) and food service workers (35%), indicating gaps in staff education and adherence to protocols.

The study also highlighted the potential role of ancillary health care personnel in transmission. Speech therapists, physical therapists, and radiology staff, who frequently moved between different units in the hospital, may have unknowingly carried C auris between patients.

The Role of Whole-Genome Sequencing (WGS)

Whole-genome sequencing (WGS) provided critical insights into the outbreak by revealing multiple distinct clusters of C auris rather than a single-source outbreak. These findings suggest that C auris was introduced to the BICU multiple times from external health care facilities and other units within the hospital. Additionally, WGS detected emerging antifungal resistance mutations, emphasizing the pathogen’s ability to adapt to treatment rapidly.

Implications for Future Infection Prevention

This outbreak highlights the urgent need for more robust infection prevention strategies, including:

• Enhanced Screening: Expanding screening protocols to include multiple body sites could improve early detection and containment of colonized patients.
• Stronger Environmental Controls: Frequent deep cleaning with high-intensity UV disinfection and improved auditing of environmental hygiene practices are necessary to prevent recontamination.
• Improved Staff Training and Accountability: Increased education and monitoring for all hospital personnel, particularly those who move between units, can reduce the risk of C auris transmission.
• Interfacility Communication: Since C auris is often introduced from other health care settings, better coordination between hospitals and long-term care facilities is essential for regional infection control.

Conclusion

The Illinois C auris outbreak underscores the difficulty of controlling this highly resilient pathogen in high-risk hospital environments. While traditional infection prevention measures remain critical, integrating genomic surveillance and more stringent environmental protocols will be key to preventing future outbreaks.

In response to the outbreak and their study, the authors stated, “WGS refined our understanding of this C auris outbreak,” the authors concluded. “The discovery that the outbreak included multiple introductions of C auris onto the unit influenced our current approach to C auris investigation and response; we focus now on between-unit transmission, including the possible role of ancillary personnel who move throughout the hospital, and not just on within-unit infection prevention measures. Furthermore, we conduct admission screening as well as point prevalence survey protocols in response to a C auris case to identify and isolate colonized patients quickly. Integrated WGS and epidemiologic investigation is a powerful tool for identifying drivers of transmission in nosocomial outbreaks.”

The lessons learned from this case serve as a wake-up call for health care facilities worldwide to strengthen their defenses against C auris and other emerging infectious threats.

The study can be found here.