Candida and Fusarium species known as opportunistic human pathogens from customer-accessible parts of residential washing machines.
Energy constraints have altered consumer practice regarding the use of household washing machines. Washing machines were developed that use lower washing temperatures, smaller amounts of water and biodegradable detergents. These conditions may favour the enrichment of opportunistic human pathogenic fungi. We focused on the isolation of fungi from two user-accessible parts of washing machines that often contain microbial biofilms: drawers for detergents and rubber door seals. Out of 70 residential washing machines sampled in Slovenia, 79% were positive for fungi. In total, 72 strains belonging to 12 genera and 26 species were isolated. Among these, members of the Fusarium oxysporum and Fusarium solani species complexes, Candida parapsilosis and Exophiala phaeomuriformis represented 44% of fungi detected. These species are known as opportunistic human pathogens and can cause skin, nail or eye infections also in healthy humans. A machine learning analysis revealed that presence of detergents and softeners followed by washing temperature, represent most critical factors for fungal colonization. Three washing machines with persisting malodour that resulted in bad smelling laundry were analysed for the presence of fungi and bacteria. In these cases, fungi were isolated in low numbers (7.5 %), while bacteria Micrococcus luteus, Pseudomonas aeruginosa, and Sphingomonas species prevailed.
Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia.
Monika Novak
MN
Babič
Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia.
Polona
P
Zalar
Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia; Centre of Excellence for Integrated Approaches in Chemistry and Biology of Proteins (CIPKeBiP), Jamova 39, 1000 Ljubljana, Slovenia.
Bernard
B
Ženko
Agricultural Institute of Slovenia, Hacquetova 17, 1000 Ljubljana, Slovenia.
Hans-Josef
HJ
Schroers
Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia; Centre of Excellence for Integrated Approaches in Chemistry and Biology of Proteins (CIPKeBiP), Jamova 39, 1000 Ljubljana, Slovenia; Jozef Stefan International Postgraduate School, Jamova 39, 1000 Ljubljana, Slovenia.
Sašo
S
Džeroski
Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia; Centre of Excellence for Integrated Approaches in Chemistry and Biology of Proteins (CIPKeBiP), Jamova 39, 1000 Ljubljana, Slovenia. Electronic address: nina.gunde-cimerman@bf.uni-lj.si.
Nina
N
Gunde-Cimerman
D001419:Bacteria / Q000145:classification / Q000302:isolation & purification; D044822:Biodiversity; D002175:Candida / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D004783:Environmental Microbiology; D005093:Exophiala / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D005670:Fusarium / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D006794:Household Articles; D006801:Humans; D016982:Micrococcus luteus; D008969:Molecular Sequence Data; D011550:Pseudomonas aeruginosa; D017422:Sequence Analysis, DNA; D017524:Slovenia; D020578:Sphingomonas
D004269:DNA, Bacterial; D004271:DNA, Fungal
Bacteria; Biofilm; Fabric softener; Fungi; Household appliances; Malodour