Molecular investigation of the incidence of Candida auris infections at selected hospitals in Iran

Abstract

BACKGROUND: The accurate occurrence rate of C. auris infections is still not clear, mainly due to the defects in detection and identification tools routinely used. In this study, we used conventional PCR and real-time PCR assays for sensitive and specific detection/identification of C. auris from either yeast isolates or clinical specimens collected from various patients in different parts of Iran. Our survey is the first large-scale study rating the incidence of C. auris infections in Iran. METHODS: A total of 439 yeast isolates and 590 clinical specimens were screened by specific C. auris-PCR, targeting the ITS region. The validity of positive samples was assessed by sequencing. RESULTS: Four out of 590 clinical specimens (0.68) were positive by conventional PCR, while in real-time PCR performed on 100 clinical samples, including those four samples positive in conventional samples, 6 samples were positive. A complete agreement of the identification of positive cases with sequencing results was documented. Among 439 culture isolates, none was positive for C. auris. After following up and resampling of the patients with positive PCR, only one specimen showed positive culture for C. auris, which was confirmed by sequencing. CONCLUSION: C. auris is not a common cause of systemic or superficial fungal infections in Iran, and a few detected positive cases can be considered as a commensal, coloniser or infecting yeast which may potentially emerge in some clinical and therapeutical conditions. Mycological and phenotypical assays are not sensitive approaches for isolation/identification of C. auris, unless a specific and sensitive molecular-based method is applied.