engleski

Year to year screening of airborne fungi in hotel environments

High levels of indoor airborne fungi could have negative impact on human health since many them are known to induce respiratory diseases particularly allergies and mucous irritations. It is well known that low efficiency filters, stagnant water and dust of air-conditioning systems can increase counts of indoor airborne fungi. The objective of this study was screening of airborne fungi in hotels (Croatia) which have air-conditioning (cooling and heating) systems. Samples were collected between March and June in 2006 (N=22), 2007 (N=22) and 2008 (N=22) using Petri plate gravitational method on 2% Sabouraud-glucose agar supplemented with antibiotics. Average levels of airborne fungi were 4.5 CFU/plate/h (2006), 4.1 CFU/plate/h (2007) and 6.6 CFU/plate/h (2008) and were not statistically differ. Aeromycological study of outdoors in Croatia conducted in the same period showed that levels of airborne fungi were significantly higher (20-40 CFU/plate/h). Also previous studies in naturally ventilated indoors obtained similar levels as it was observed outdoors. Frequency and composition of aeromycota in hotels showed year to year similarity. Species of Cladosporium (59-63%) and Penicillium (41-63%) dominated over Alternaria (18-27%), Aspergillus (18-22%), Acremonium and Epicoccum (13-18%). Other detected fungi recovered from 4.5 to 9% of samples. In the second step 4 isolates of penicillia and 10 isolates of aspergilla were screened for ochratoxin A (OTA) and sterigmatocystin (ST) production by TLC semiquantitative method. Among isolates only one strain of P. verrucosum was able to produce OTA (6 mg/kg). Our earlier screening of outdoor Aspergillus isolates detected 6/18 A. verisicolor ST-producers (3.8-120 mg/kg). Taking into account detected levels of airborne fungi in hotels we could conclude that risk of fungal respiratory diseases and toxicoses is very low. The results also suggest that air-conditioned systems which are well designed and well-maintained could reduce the levels of potentially toxigenic airborne fungi in particular indoor environments.

fungal allergies; Cladosporium; Alternaria; HVAC systems

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