Eeva-Liisa Hintikka

Mycotoxins in Crude Building Materials from Water-Damaged Buildings

ABSTRACT We analyzed 79 bulk samples of moldy interior finishes from Finnish buildings with moisture problems for 17 mycotoxins, as well as for fungi that could be isolated using one medium and one set of growth conditions. We found the aflatoxin precursor, sterigmatocystin, in 24% of the samples and trichothecenes in 19% of the samples. Trichothecenes found included satratoxin G or H in five samples; diacetoxyscirpenol in five samples; and 3-acetyl-deoxynivalenol, deoxynivalenol, verrucarol, or T-2-tetraol in an additional five samples. Citrinine was found in three samples. Aspergillus versicolor was present in most sterigmatocystin-containing samples, and Stachybotrys spp. were present in the samples where satratoxins were found. In many cases, however, the presence of fungi thought to produce the mycotoxins was not correlated with the presence of the expected compounds. However, when mycotoxins were found, some toxigenic fungi usually were present, even if the species originally responsible for producing the mycotoxin was not isolated. We conclude that the identification and enumeration of fungal species present in bulk materials are important to verify the severity of mold damage but that chemical analyses are necessary if the goal is to establish the presence of mycotoxins in moldy materials.

Experimental lung mycotoxicosis in mice induced by Stachybotrys atra

Stachybotrys atra is often isolated from building materials in houses with moisture problems. Spores of S. atra can contain mycotoxins which may lead to various symptoms in exposed residents in damp houses. The pathogenesis of S. atra‐induced lung diseases has not been elucidated. The purpose of the present study was to investigate lung mycotoxicosis experimentally in mice after an intranasal exposure to spores of S. atra‐fungus. One group of mice received one intranasal injection of spores of a toxic strain of S. atra (1 × 106 spores) and the other group spores of a less toxic strain. Spores of both strains contained spirolactones and spirolactams while the highly toxic strain contained also trichothecene mycotoxins, satratoxins. The spores containing satratoxins caused severe intra‐alveolar, bronchiolar and interstitial inflammation with haemorrhagic exudative processes in the alveolar and bronchiolar lumen. A significant difference was observed in the severity of the lung damage caused by the two strains of S. atra. The spores without satratoxins induced a milder inflammation, so that the toxic compounds of S. atra‐spores are most likely responsible for the severity of the lung injury.

Laboratory experiments on membrane filter sampling of airborne mycotoxins produced by Stachybotrys atra corda

Abstract A membrane filter method for sampling of airborne stachybotrystoxins was studied in the laboratory. Toxigenic strains of Stachybotrys atra on wallpaper, grain, hay and straw were used as toxin sources in the experiments. Air samples were collected on cellulose nitrate and polycarbonate membrane filters at air flow rates of 10–20 l min −1 . After the filter sampling, the air was passed through methanol. The results showed that stachybotrystoxins (trichothecenes) were concentrated in airborne fungal propagules, and thus can be collected on filters. Polycarbonate filters with a pore size of 0.2 μm collected the highest percentage of toxic samples. The laboratory experiments indicated that polycarbonate filter sampling for the collection of airborne mycotoxins is a promising method for extension to field measurements.

Stachybotrys Atra Corda May Produce Mycotoxins in Respirator Filters in Humid Environments

This paper examines the growth and toxin production of Stachybotrys atra, a cellulose-decomposing fungi, in two respirator filters with different ratios of cellulose and fiberglass at relative humidities of air (RH) 78–100% for 86 days. The results show that S. atra can grow only in filter material of high cellulose content. S. atra grew slightly at RH 84–89%, but did not produce toxins. Under saturated conditions, S. atra grew and produced satratoxin H regardless of variation in temperature. The present study indicates that S. atra can grow on cellulose-containing filter material and produce toxins in the filter under humid conditions.

Comparison of detection methods for trichothecenes produced by Fusarium sporotrichioides on fodder and grains at different air humidities.

Growth and toxin production of a highly toxic strain of Fusarium sporotrichioides Sherb were studied on oat and wheat grains and on straw under experimental conditions, in which relative humidity (RH) of air was regulated. The materials were incubated at three different RH levels at a range of 84-100%. F. sporotrichioides grew well on oat and wheat grains at RH 97-100% but grew less well at RH 84-88% and on straw. Toxin production was measured with three biological toxicity tests (cytotoxicity test, dermotoxicity test, and yeast cell toxicity test), with chemical analysis, and T-2 ELISA assay. Cytotoxicity and production of trichothecene mycotoxins were detected in all the samples incubated at all three RH levels. On oat and wheat grains, T-2 toxin, neosolaniol, and diacetoxyscirpenol were found, and on straw T-2 toxin, HT-2 toxin, neosolaniol, and T-2 tetraol were determined. In the T-2 ELISA assay, all material samples were found to contain T-2 toxin. The cytotoxicity test was the most sensitive method for detecting biological toxicity of samples inoculated with fungus. The T-2 ELISA assay and chemical analysis were about equally sensitive to detect T-2 toxin in samples.

Occurrence of Trichothecenes in feed and cereals in Finland.

In 1985 82 samples of feed and food grain were analyzed for trichothecenes deoxynivalenol (DON), nivalenol (NV), diacetoxyscirpenol (DAS), T-2 toxin, HT-2 toxin and fusarenon-X (F-X). Trichothecenes were found in 77 of these samples. The highest amounts were DON 6300 ug/kg and DAS 1680 ug/kg.In 1986, in a corresponding study of 113 samples, trichothecenes were found in 110 samples. A new trichothecene in Finland, 3-acetyldeoxynivalenol (3-AcDON), was identified in 35 of these samples in concentration of 2–211 ug/kg.Analyzing methods were gas chromatography and GC-mass spectrometry. It is characteristic of the feed samples suspected of causing outbreaks in animals in Finland that several trichothecenes are often found in the same sample. As an example of this is a poultry feed with following results: DON 33 ug/kg, 3-AcDON 21 ug/kg, DAS 45 ug/kg, T-2 toxin 40 ug/kg, HT-2 toxin 12 ug/kg.