Factors associated with hospital-acquired Candida auris in a DC hospital

Abstract

From August 2021 to July 2024, a teaching hospital in the DC area experienced a considerable increase in hospital-acquired (HA) Candida auris cases. This project identified possible contributing factors and implemented targeted interventions, which helped reduce the monthly HA case rate and likelihood of an outbreak.

Background

Candida auris (C. auris), a multidrug-resistant fungus, is a major public health concern owing to its inherent resistance to available antifungals and frequent misidentification by conventional laboratory methods. ^1–3 Because of these characteristics, it has been implicated in healthcare-associated outbreaks, particularly in acute-care settings, due to its ability to persist in the environment and ease of transmission. ^2,4,5

Setting

A 477-bed acute-care, teaching, and research hospital in Washington, DC, experienced a notable increase in HA C. auris cases, with cases identified across both medical-surgical and intensive care units.

Objective

To inform targeted mitigation strategies, the facility sought to identify the factors associated with increases in HA C. auris cases between August 2021 and July 2024.

Methods

Cases were identified using TheraDoc, an electronic clinical surveillance system. Demographic and clinical data were retrospectively extracted from electronic medical records (EMR). HA cases were defined as the identification of C. auris from any site on or after hospital day 4. Cases were classified as clinical if C. auris was identified from a diagnostic culture or colonization if identified via surveillance swab. ⁶

HA incident rates were calculated as the number of incident HA cases divided by total patient days during the study period, expressed per 10,000 patient days:

To assess the impact of interventions, incidence rates pre- and post-intervention were compared using a two-sample Poisson rate test, with statistical significance set at P < .05. Analyses were performed using the National Healthcare Safety Network statistic calculator.

Results

A total of 54 patients were identified during the study period, of whom 35 (65%) met criteria for HA infection. Among these, 71% were male, with a median age of 64 years. Most patients had clinical infections rather than colonization, and the average time to positivity was 24 days. Notably, 63% of patients had a length of stay of 28 days or more, and 46% had co-infections with other multi-drug resistant organisms (MDROs) (see Table 1 for detailed data). These findings are consistent with known risk factors for C. auris acquisition. ^2,3

Table 1.

Descriptive characteristics of hospital-acquired cases

	N = 35	Percent
Sex
Male	25	71
Female	10	29
Age group
<= 39	1	3
40–49	4	11
50–59	8	23
60–69	11	31
70–79	4	11
80–89	6	17
90–99	1	3
Average	64
Case type
Colonization	10	29
Clinical	25	71
Length of stay
<7 d	1	3
7–13 d	3	9
14–20 d	5	14
21–27 d	4	11
>= 28 d	22	63
Average	64
Median	38
IQR	55.25
Indwelling device
Central line only	9	26
Urinary catheter only	4	11
Central line and urinary catheter	12	34
No	10	29
Sub-acute rehab in past 90 d
Yes	15	43
No	19	54
Unknown	1	3
Other MDRO
1 MDRO	10	29
>= 2 MDROs	6	17
No	19	54
Outpatient wound clinic
Yes	13	37
No	22	63
Time to positivity
Average (days)	24
Minimum (days)	4
Maximum (days)	399

Note. IQR, interquartile range.

The crude HA incidence rate was 1 case per 10,000 patient days. Incident rate analysis demonstrated a significant reduction post-intervention: the rate decreased from 1.88 to .75 cases per 10,000 patient days (P = .0127) as shown in Figure 1.

Figure 1.

Case rate trend, pre- and post-interventions.

Discussion

The contributing factors can be classified into 2 major categories: operational and laboratory gaps and environmental and clinical practice gaps.

Operational and laboratory gaps

Early in the study period, the facility was unable to perform in-house C. auris testing, which necessitated coordination with the local health department for analysis at a regional public health laboratory. This process led to extended transmission-based precautions for patients due to prolonged turnaround times. Additionally, notification delays from the Department of Health complicated admission management and interfacility transfers. Once internal testing began, delays in interpreting results within the EMR hindered timely implementation of transmission-based precautions. Furthermore, the absence of a standardized definition of hospital-acquired (HA) Candida auris may have contributed to over- or underestimation of true case counts.

Environmental and clinical practice gaps

Audits revealed inconsistent low-level disinfection practices across nursing units, particularly regarding adherence to required disinfectant contact times. Similar variability was observed in the cleaning of high-touch surfaces by environmental services staff (EVS). These inconsistencies suggested a need for more robust staff education and process standardization.

Screening practices were also limited, initially focusing on select facilities, potentially missing patients from other high-burden facilities. Moreover, clinical staff demonstrated knowledge gaps in recognizing patients who were known to be positive or under evaluation for infection. This lack of awareness further increased the risk of in-hospital transmission.

Interventions

To address the rise in HA cases, the facility implemented a multidisciplinary “Identify-Isolate-Inform” strategy.

Identify

Collaboration with the informatics team led to flagging patients admitted from high-risk facilities within the EMR. Screening protocols were expanded from the emergency department to include all admissions from nursing homes and sub-acute and rehab facilities in the metropolitan area. Once a positive result is identified, the patient’s EMR is flagged for all future admissions. ⁷ Additionally, the laboratory began speciating all Candida isolates to promptly detect all patients with infections and colonization.

Isolate

The Infection Prevention and Control Department developed a new isolation precaution sign for confirmed or suspected C. auris cases entitled Special Contact Isolation. The signage clearly outlined the necessary personal protective equipment and emphasized the use of germicidal wipes for disinfecting shared patient equipment and high-touch surfaces within the patient rooms. ⁸

Periodic audits were conducted using fluorescent markers and blacklight, or surface swabs for adenosine triphosphate, to assess the adequacy of disinfection and cleaning practices among nursing and EVS. ⁹ Feedback was shared with unit leadership, and just-in-time education was provided to reinforce best practices.

Inform

Education was delivered to all direct care staff covering C. auris prevalence, pathogenicity, and transmission-based precautions. ¹⁰ Nurse managers received quick checklists to support adherence to infection prevention protocols.

A formal notification procedure was established whereby the microbiology lab would notify the Infection Prevention department or infectious diseases physicians of all positive C. auris isolates.

The local health department was notified of all confirmed cases to support regional containment efforts. ⁷ Additionally, receiving facilities were notified prior to patient transfers to ensure continuity of care. ³

Although the facility has maintained a case rate of .75 per 10,000 patient days, challenges persist in identifying rule-out cases due to the absence of a specific order for Special Contact Isolation in the EMR. This has been ameliorated by establishing a daily review of a page in the EMR that lists all patients with an order for the C. auris screening test, but as this is a manual process, it may be prone to practice drift.

Limitations

This study was limited to data documented in the patients’ EMR, which may have overlooked other additional contributing factors. ³ It did not assess the low-level disinfection practices of respiratory and other therapy staff, potentially missing other vectors for transmission. Furthermore, the lack of a nationally standardized definition for HA C. auris may have led to inaccuracies in case counts compared to other MDROs.

Conclusion

The implementation of targeted, multidisciplinary interventions contributed to a significant reduction in the HA case rate and lowered the risk of an outbreak. Establishing a standardized definition would assist facilities in monitoring and benchmarking internal infection cases. Further research is needed to evaluate infection prevention compliance in outpatient wound clinics, which may serve as reservoirs for community transmission.

Data availability statement

During the preparation of this work, Dietrich and Tara Millson used OpenAI ChatGPT for grammar and readability. After using this tool/service, the author reviewed and edited the content as required and took full responsibility for the content of the publication.

Financial support

None.

Competing interests

No conflicts of interest for any of the authors.

Ethical standard

This manuscript is original work and does not duplicate any other previously published work. This manuscript has only been submitted to this journal and is not under consideration for publication elsewhere. All listed authors are aware of and agree to the submission of this manuscript to the journal. The manuscript contains nothing abusive, defamatory, fraudulent, illegal, libelous, or obscene. This manuscript has received IRB approval.