Candidozyma auris in hospital setting: Molecular characterization of clinical and environmental strains

Candidozyma auris is a yeast that has a strong ability to adapt, can cause serious invasive infections and contaminate various surfaces.

After cases of C. auris have occurred in patients hospitalized in a healthcare facility of Apulia region, Italy, clinical and environmental surveillance was implemented. The aim of this study is to perform genotypic and phenotypic characterization between clinical and environmental isolations. In August and September 2024, in three hospital wards, axillary-inguinal swabs were performed on hospitalized patients; environmental monitoring was carried out simultaneously to detect C. auris in air and surfaces.

C. auris strain was isolated from the blood culture and peritoneal fluid of a patient, and identified using mass spectrometry. Swabs were performed on surfaces in the patient's room using sterile swabs, analyzed by molecular method. Active and passive sampling of air was conducted. Out of the 194 surface swabs, C. auris DNA was detected in 50 samples. Passive air sampling identified C. auris in 33.3% of plates in Intensive Care patient areas. In the Infectious Diseases Unit, a sample tested positive. Active air sampling didn't detect C. auris. 66 patients were screened, all of which resulted negative for C. auris. Swabs collected from two patients were positive. All isolates were susceptible to amphotericin B, anidulafungin and resistant to fluconazole. Amino acid substitutions were identified in the ERG11 and TAC1B genes.

Viable C. auris was detected in a small number of environmental samples and was genetically closely related to isolates from the corresponding patients.