Fungal colonization of air-conditioning systems and indoor cultivated plants and its relation to human health

Fungi have been implicated as quantitatively the most important bio-aerosol component of indoor air associated with contaminated air-conditioning systems and soil of indoor cultivated plants. The objectives of this study were not only to assess the level of fungal contamination in the filter dust of air conditioning systems and soil of indoor cultivated potted plants present inside homes, offices and hospitals for one year, but also fungal identification and examination of their potentiality to produce extracellular hydrolytic enzymes. A total of 5740 fungal colony-forming units (CFU) were collected belonging to 57 fungal species. The predominant molds isolated were Aspergillus spp., Penicillium spp., Cladosporium spp. and Fusarium spp. Enzymatic activity test of the isolated fungi revealed that many isolates showed cellulolytic and keratinolytic activity. In addition, some isolates showed lipolytic, proteolytic and hemolytic activity and could grow at 37oC, which indicate their pathogenic potentiality as human opportunistic pathogens. The results of this surveillance study indicated that in the case of CF, the abundance of fungal colonies was much higher in homes than offices and hospitals while in case of CP, it was much higher in hospitals followed by offices and homes. It is important to stress that fungal colonization of air-conditioning systems and soil of potted plants should not be ignored and to educate homes, offices and hospitals about the need of routine cleaning and disinfection of gadgets like air-conditioning systems and soil of cultivated plants for minimizing the chances of proliferation and dispersal of potentially pathogenic fung.