Environmental Detection of Candidozyma (Candida) auris in Surface Waters of the Gediz Delta, a Critical Coastal Wetland in Türkiye: Expanding One Health Surveillance Perspective.

内容摘要

Candidozyma auris (syn. Candida auris) is an emerging multidrug-resistant yeast of growing clinical and environmental concern. Despite its increasing detection in healthcare settings worldwide, environmental evidence remains scarce. This study presents the first molecular detection of C. auris DNA in surface waters of Türkiye, within the Ramsar-protected Gediz Delta, as part of the national One Health Surveillance Framework. A total of 80 surface-water samples were collected from five wetland ecosystems Tuz Lake, Kulu Lake, Göksu Delta (Akgöl and Paradeniz Lagoons), Kızılırmak Delta, and Gediz Delta. Physicochemical parameters; temperature, pH, and salinity were recorded in situ using a multi parameter sensor. Environmental DNA was extracted from 2 L of 0.22 µm Sterivex-filtered water and analyzed via qPCR using C. auris-specific (CauF/CauR) and Candida-genus (CauRelF/CauRelR) primer sets. Yeast isolation was performed on CHROMagar™ Candida Plus, and identification was achieved by MALDI-TOF MS. C. auris DNA was detected in one sample (1.25%), specifically from the Gediz Delta (Sample No. 5651, 38.523° N, 26.892° E), with Ct values 33.8-37.2 confirmed by sequencing. Broader Candida genus signals were observed in 24% of samples. Culture-based analyses yielded no viable C. auris, but 15 yeast isolates were identified, mainly Pichia kudriavzevii (Candida krusei), C. albicans, and Nakaseomyces glabratus (Candida glabrata). The culture-negative yet qPCR-positive finding indicates that C. auris DNA likely persists in aquatic environments as non-viable or residual material. This finding provides early molecular evidence of environmental dissemination and underscores the need for viability assays, culture-based isolation, and metagenomic monitoring integrated within One Health surveillance programmes.