High Incidence of an Emerging Opportunistic Pathogen Candida parapsilosis in Water-Related Domestic Environments

Abstract

Candidiasis is one of the common fungal opportunistic infections, usually associated with diverse Candida species. Candida albicans, C. glabrata complex, C. parapsilosis complex, C. tropicalis and C. auris are often identified in affected patients. Candida parapsilosis sensu stricto is an emerging cause of hospital-acquired Candida infections, predominantly in Southern Europe, South America and Asia. Home envi- ronment is a less known source of infection despite frequent isolation of C. parapsi- losis from kitchen surfaces and household appliances such as dishwashers, washing machines and refrigerators. C. parapsilosis is one of the first colonisers of novel dishwashers and a member of stable fungal communities on rubber seals worldwide in concentrations up to 102 CFU/cm2. It colonises also drawers for detergents in wash- ing machines and drainage channels in refrigerators. Tap water and groundwater act as vector for entrance of C. parapsilosis in the indoor environments. Within C. parapsilosis, four clinically relevant phenotypes can be distinguished. Experimental data on the prevalence of C. parapsilosis isolates phenotypes, obtained from indoor environments, will be presented. Smooth phenotype prevails in dishwashers and washing machines, while crepe and crater dominate in water. In conclusion, the abil- ity to colonise diverse environments and accordingly switch phenotypes defines C. parapsilosis as a versatile, domestic environment-related opportunistic pathogen.