Species diversity and cytotoxic potency of airborne sterigmatocystin-producing Aspergilli from the section Versicolores Daniela Jakšić Despot a , Sandor Kocsubé b , Ottó Bencsik b , Anita Kecskeméti b , András Szekeres b , Csaba Vágvölgyi b , Janos Varga b , Maja Šegvić Klarić a, ⁎ a Department of Microbiology, Faculty of Pharmacy and Biochemistry, University of Zagreb, Schrottova 39, 10000 Zagreb, Croatia b Department of Microbiology, Faculty of Science and Informatics, University of Szeged, H-6726 Szeged, Közép fasor 52, Hungary HIGHLIGHTS • Abundance and species diversity of indoor STC-producing Aspergillus (Versicolores) • Based on CaM sequences indoor air comprised seven species of Versicolores. • All isolates produced STC but with differences in production capacity. • High STC levels in grain mill dust indicated the contamination with STC-producers. • STC and Aspergilli are cytotoxic in concentrations that can be detected indoors. GRAPHICAL ABSTRACT abstract article info Article history: Received 2 February 2016 Received in revised form 24 March 2016 Accepted 25 March 2016 Available online 18 April 2016 Editor: D. Barcelo This study presents the distribution and species diversity of sterigmatocystin-producing Aspergilli from the sec- tion Versicolores in the indoor air of apartment-AP, basements-BS and grain mill-GM in Croatia, as well as the cy- totoxic potency of isolates. The species comprised 0.7–20% of total airborne fungi detected in the AP, 11–55% in the BS, and 0–2% in the GM. Based on CaM sequences, seven species were identified; dominant were Aspergillus jensenii and Aspergillus creber, followed by Aspergillus protuberus, Aspergillus venenatus, Aspergillus tennesseensis, Aspergillus amoenus, Aspergillus griseoaurantiacus and three undescribed species. All of the identified species produced sterigmatocystin-STC (HPLC/UV-VIS); A. griseoaurantiacus (208.29 μg/mL) and A. jensenii (1.192–133.63 μg/mL) produced the highest levels, the lowest were detected in A. protuberus and A. tennesseensis (0.117–2.749 μg/mL). Lower species diversity was obtained in the GM due to overgrowth with more propulsive fungi. Relatively high STC levels (0.06–2.35 μg/g) detected in 52% of GM dust samples confirmed the presence of STC-producers, although this STC cannot be exclusively attributed to Aspergilli (Versicolores). STC and the majority of STC-producing Aspergilli were cytotoxic to human lung A549 cells (IC 50 0.9–2.3 μg/mL) and THP-1 macrophage-like cells (IC 50 0.3–0.6 μg/mL) in relatively low concentrations suggesting that humans can be at high risk during chronic exposure. © 2016 Elsevier B.V. All rights reserved. Keywords: Versicolores Airborne fungi Mycotoxin Sterigmatocystin Cytotoxicity Dust Science of the Total Environment 562 (2016) 296–304 ⁎ Corresponding author. E-mail address: msegvic@pharma.hr (M.Š. Klarić). http://dx.doi.org/10.1016/j.scitotenv.2016.03.183 0048-9697/© 2016 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv