Dishwashers as an Extreme Environment of Potentially Pathogenic Yeast Species

Abstract

The study aimed to compare the yeast species diversity in the specific environment of dishwashers, taking into account the potential risk for users. Yeasts were isolated from ten dishwashers and from tap water supplied to the appliances. Samples were collected for mycological analyses at the beginning of each month, from February to May 2016. Four dishwasher sites (rubber seals, detergent dispensers, sprinklers, and water drains) were analyzed. The microfungi were identified by the standard procedures applied in mycological diagnostics. To confirm species identification, molecular analysis was performed based on the sequences of the D1/D2 region. The presence of microfungi was detected in 70% of the investigated appliances. Rubber seals, detergent dispensers, and water drains were the most frequently colonized elements. Thirty-five yeast strains were isolated in this study, of which twenty-seven were obtained from dishwashers and eight from tap water. The strains belonged to six genera and six species (Candida parapsilosis, Clavispora lusitaniae, Dipodascus capitatus, Exophiala dermatitidis, Meyerozyma guilliermondii, and Rhodotorula mucilaginosa). Most of the strains came from rubber seals. In this way, it was demonstrated that the dishwashers’ condition is sufficient as an ecological niche for microfungi.

Microbial diversity and proxy species for human impact in Italian karst caves

“…The predominance of Candida www.nature.com/scientificreports/ genus, which includes many species known as common colonizers of humans, in show -caves may reflect a relation with touristic flow. Candida has also been reported as an oligotrophic multi-stress tolerant fungus, skilled to colonize a wide range of natural, urbanized and human environmental contexts 22,23 . Cave visitors, as previously reported, may act as primary vector in the spreading of this genus, by bio-aerosols formation (breathing, sneezing or coughing), surface contact and shedding of skin scales, hair and lint from clothing 24 .…”

Window seals as a source of yeast contamination

“…In this study, a wide spectrum of yeast species, mainly basidial fungi, with very high adhesion properties, micellar and biofilm formation were isolated from seals' surface. Similar characteristics of yeast were observed on the dishwasher (Zalar et al 2011;Zupan ci c et al 2016;Raghupathi et al 2018;Kulesza et al 2021) and washing machine seals (Babi c et al 2015;D€ og ˇen et al 2017;Tischner et al 2019). Besides adherence to surfaces, fungi need water, nutrients and regulatory substances to survive on seals.…”

“…Colonized window seal surfaces can be a source of building contamination. In favourable conditions, the fungal biofilm cells can be released from the matrix (Lagree and Mitchell 2017), spread aerogenously to other rooms (Fr€ ohlich-Nowoisky et al 2009), colonize seals (Zalar et al 2011;Babi c et al 2015;Zupan ci c et al 2016;Kulesza et al 2021) and other polyurethane materials (Loredo-Treviño et al 2011). An example is A. pullulans, classified as a primary colonizer with a very high ability to create a biofilm.…”

“…Moreover, the seals are made of poly (ether urethane) foam, which gives them high adhesive properties, further increasing the potential of this site as a habitat for fungi, especially yeasts. Numerous research studies have shown many fungi species on the seals of sinks (Zupan ci c et al 2016) and appliances, such as refrigerators (Altunatmaz et al 2012;Lalitha 2019;Novak Babi c et al 2020), washing machines (Babi c et al 2015;D€ og ˇen et al 2017;Tischner et al 2019) and dishwashers (Zalar et al 2011;Zupan ci c et al 2016;Raghupathi et al 2018;Kulesza et al 2021).…”

Biocontrol Potential of Sodin 5, Type 1 Ribosome-Inactivating Protein from Salsola soda L. Seeds

“…Finally, we tested two ubiquitous yeasts, Candida parapsilosis and Rhodotorula mucilaginosa , which are often isolated from habitats associated with human and anthropogenic pollution [ 55 , 56 ]. They can be isolated from seawater and salty mud [ 57 , 58 ], but are not primarily associated with salterns or halophytes, which may partly explain their susceptibility to sodin 5.…”