Whole Genome Sequencing Use in Confirming a Pseudo-Outbreak of Candida parapsilosis in an Acute Care Hospital ¡ª Nebraska, 2023

What did we do?

• Candida parapsilosis (CP) is a yeast known to cause invasive infection. During January–July 2023, an acute care hospital in Nebraska observed an increase among patients with CP cultured (9 cases vs 1–6 cases/year during 2019–2022). The Nebraska Department of Health and Human Services investigated to determine outbreak source.

What did we find?

• During January 1–September 18, 2023, 20 patients with CP cultured were identified; 10 (50%) were female and 19 (95%) were White, not Hispanic or Latino. Median age was 65 years (range: 45–91 years).
• No common healthcare-associated exposures or risk factors were identified among patients, and all cultures were performed within the hospital's microbiology laboratory.
• Infection prevention and control (IPC) deficiencies included improper preparation of cleaning solution and lack of standard disinfection protocols for microbiology laboratory equipment.
• Whole genome sequencing found genetically similar CP isolates from 11 of 12 available patient cultures and five environmental cultures of a vortex, plate-rack, and anaerobic collection jars within the microbiology laboratory culture preparation biosafety cabinet.
• After removal of contaminated equipment, decontamination of laboratory surfaces, and updating IPC practices, no additional genetically similar CP cultures have been identified.

Why does it matter?

• Laboratory contamination with CP was identified as the pseudo-outbreak source. This investigation highlights WGS as an epidemiologic tool to enhance patient safety by differentiating between contamination and true infection in a healthcare environment.

Abstract Category: Fungal Diseases, Healthcare-Associated Infections