25 giugno 2011

Lavastoviglie o allevamento di microorganismi?

lavastoviglie Un articolo scientifico pubblicato sul periodico della British Mycological Society, Fungal Biology, avverte: la lavastoviglie può diventare un allevamento di funghi potenzialmente nocivi. Più della metà dei campioni (il 62%) prelevati dalle guarnizioni di gomma delle lavastoviglie conteneva i funghi Exophiala dermatitidis e Exophiala phaeomuriformis. Entrambe le specie di Exophiala sono tristemente famose: possono colonizzare i polmoni dei pazienti con fibrosi cistica. Lo studio ha riguardato 189 lavastoviglie usate in appartamenti di 18 Paesi.

Dishwashers – A man-made ecological niche accommodating human opportunistic fungal pathogens
P. Zalar (Biology Department, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia), M. Novak (Centraalbureau voor Schimmelcultures Fungal Biodiversity Centre, Utrecht, The Netherlands), G.S. de Hoog (Centraalbureau voor Schimmelcultures Fungal Biodiversity Centre, Utrecht, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands, Peking University Health Science Center, Research Center for Medical Mycology, Beijing, China, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China), N. Gunde-Cimerman (Centre of Excellence for Integrated Approaches in Chemistry and Biology of Proteins, CIPKeBiP, Jamova 39, SI-1000 Ljubljana, Slovenia).
Habitats in human households may accommodate microorganisms outside the common spectrum of ubiquitous saprobes. Enrichment of fungi that may require specific environmental conditions was observed in dishwashers, 189 of which were sampled in private homes of 101 towns or communities. One-hundred-two were sampled from various localities in Slovenia; 42 from other European countries; 13 and 3 from North and South America, respectively; 5 from Israel; 10 from South Africa; 7 from Far East Asia; and 7 from Australia. Isolation was performed on samples incubated at 37 °C. Species belonging to genera Aspergillus, Candida, Magnusiomyces, Fusarium, Penicillium and Rhodotorula were found occasionally, while the black yeasts Exophiala dermatitidis and Exophiala phaeomuriformis (Chaetothyriales) were persistently and most frequently isolated. Sixty-two percent of the dishwashers were positive for fungi, and 56 % of these accommodated Exophiala. Both Exophiala species are known to be able to cause systemic disease in humans and frequently colonize the lungs of patients with cystic fibrosis. We conclude that high temperature, high moisture and alkaline pH values typically occurring in dishwashers can provide an alternative habitat for species also known to be pathogenic to humans.

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