Frequency of sterigmatocystin (STC) and 5-methoxysterigmatocystin (5-MET-STC)-producing airborne Aspergilli from flooded and unflooded area in Croatia

Abstract

STC-producing Aspergilli, frequently airborne in damp dwellings, could contribute to STC intake by inhalation. In addition, 5-MET-STC could be produced simultaneously resulting with alternating toxic effects. The purpose of this study was to compare STC/5- MET-STC producing abilities of airborne Aspergilli (sect. Versicolores) collected in September 2016 from flooded village (5 repaired/ 5 unrepaired houses and a school) and unflooded control village (5 houses and a school) in Croatia. STC and 5-MET-STC detection were performed by HPLC-DAD-ESI/MS/MS gradient method. STC-producing Aspergilli were more frequent in flooded village compared to control village (40–100 % ; 702 ± 975 CFU/m3). They were isolated from 2/5 unrepaired houses, 5/5 repaired houses and in school from the flooded area, while in the control village they were present in 1/5 houses. STC/5-MET-STC producing abilities were similar for all the isolates (N=14) despite the location. 10/14 isolates produced both STC and 5-MET-STC (1.97 ± 1.05 μg/mg and 5.06±2.90 μg/mg, respectively) while 2/14 produced only STC (4.48 ± 2.56 μg/mg) and 1/14 only 5-MET-STC (6.05 μg/mg ). Significantly higher concentrations of STC/5- MET-STC-producing airborne Aspergilli in flooded houses suggest increased health risk due to expected STC/5-MET-STC content in inhalable airborne particles. Health effects due to the co-occurrence of STC and 5-MET-STC should be further explored.