Post-Flood Impacts on Occurrence and Distribution of Mycotoxin-Producing Aspergilli from the Sections Circumdati, Flavi, and Nigri in Indoor Environment

Abstract

Mycotoxin-producing Aspergilli (Circumdati, Flavi, and Nigri), usually associated with contaminated food, may also cause respiratory disorders and are insufficiently studied in water-damaged indoor environments. Airborne (N = 71) and dust borne (N = 76) Aspergilli collected at post-flood and control locations in Croatia resulted in eleven different species based on their calmodulin marker: A. ochraceus, A. ostianus, A. pallidofulvus, A. sclerotiorum, and A. westerdijkiae (Circumdati); A. flavus (Flavi); and A. tubingensis, A. welwitschiae, A. niger, A. piperis, and A. uvarum (Nigri). Most of the airborne (73%) and dust borne (54%) isolates were found at post-flood locations, and the highest concentrations measured in indoor air (5720 colony-forming units (CFU)/m3) and dust (2.5 × 105 CFU/g) were up to twenty times higher than in the control locations. A. flavus dominated among airborne isolates (25%) at the unrepaired locations, while 56% of the dust borne Aspergilli were identified as A. tubingensis and A. welwitschiae. The ability of identified isolates to produce mycotoxins aflatoxin B1 (AFB1), fumonisin B2 (FB2), and ochratoxin A were assessed by LC-MS analysis. All ochratoxin A (OTA)-producing Circumdati belonged to A. westerdijkiae (13.7 ± 15.81 µg/mL); in the section, FlaviA. flavus produced AFB1 (2.51 ± 5.31 µg/mL), while A. welwitschiae and A. niger (section Nigri) produced FB2 (6.76 ± 13.51 µg/mL and 11.24 ± 18.30 µg/mL, respectively). Water damage dominantly supported the occurrence of aflatoxigenic A. flavus in indoor environments. Yet unresolved, the causal relationship of exposure to indoor Aspergilli and adverse health effects may support the significance of this research.

Underreported Human Exposure to Mycotoxins: The Case of South Africa

“…Flooding before the maize harvest in Argentina resulted in more than 65% of samples tested being above the mycotoxin risk threshold [ 59 ]. Jakšić et al [ 60 ] exclusively reported the presence of aflatoxigenic species A. flavus at post-flood locations. Since water is a major promoter of fungal proliferation [ 61 ], the expected aftermath of flooding is even higher, as the occurrence of flood creates a moist environment conducive for fungal growth and mycotoxin production.…”

Loading Rates of Dust and Bioburden in Dwellings in an Inland City of Southern Europe

“…Additionally, the exclusive identification by MEA of Aspergillus sections Fumigati and Flavi and Circumdati section in DG18 increases the importance of applying different culture media to acknowledge the Aspergillus contribution to fungal contamination [32]. In fact, the presence indoors of Aspergillus section Fumigati represents a major risk for the onset and development of respiratory diseases in immunocompromised individuals [47,48], while sections Flavi and Circumdati, major producers of aflatoxin B1 and ochratoxin, respectively, represent the potential exposure to these mycotoxins [3,44,49].…”

“…Atmosphere 2021, 12, x FOR PEER REVIEW 7 of 16 onset and development of respiratory diseases in immunocompromised individuals [47,48], while sections Flavi and Circumdati, major producers of aflatoxin B1 and ochratoxin, respectively, represent the potential exposure to these mycotoxins [3,44,49].…”

Combined Toxicity of the Most Common Indoor Aspergilli

“…Because of their biomedical and economical significance, special importance among indoor Aspergilli is given to those from the section Flavi and series Nigri (ex-section Nigri ) and Versicolores (ex-section Versicolores ), among which A. flavus , A. tubingensis , A. welwitschiae , A. jensenii and A. creber are the most commonly identified species [ 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. The ability to tolerate a range of the water activities (a w ) 0.75–0.90, a wide range of pH and ionic strength make Aspergilli particularly common indoor fungi [ 18 ].…”

“…Indoor dust contains both indoor and outdoor fungi brought from various outdoor sources and thus it is the most representative sample for assessment of human exposure [ 29 ]. Aspergilli from the section Flavi and series Nigri and Versicolores have been frequently identified in indoor dust samples from around the world [ 13 , 30 , 31 , 32 ]. In addition, Aspergilli metabolites have also been identified in various indoor dust samples [ 9 , 33 , 34 , 35 ].…”