Mould growth on building materials - Statens Byggeforskningsinstitut

ing over some time) recovered from the lung. The bedroom of the child was heavily infested
with S. chartarum and air samples revealed 6×10 4 CFU/m 3 of the fungus.
From St. Louis there is also a report 27 on a case of IPH in an infant, who was exposed to
fungi during a 2 weeks holiday. On the return trip the infant developed the hemorrhage upon
exposure to tobacco smoke. Low quantities of hemosiderin in macrophages in the lung indicated
no preceding bleedings. During the vacation (14 days) the infant had resided in a room
with visible mould <strong>growth</strong> of Trichoderma, Penicillium, Cladosporium and Ulocladium.
Recently a fatal IPH case has been discovered in Belgium (N. Nolard, personal communication),
in this case airborne spores were detected, they were released in high numbers due to
constructional work in the bathroom.
2.4 Biologically active metabolites from moulds
Microfungi have the ability to produce a high number of secondary metabolites, which they
for various reasons need in their natural habitat 169,170 . Most of these are produced as a response
to other organisms especially other fungi 171 . Some of these metabolites can cause a
toxic response "when introduced by a natural route in low concentrations to higher vertebrates
and animals" and are referred to as mycotoxins 172 .
Sorenson 173 and Miller 69 were some of the first to realise the implications of mycotoxins in the
indoor environment. The latter emphasises that moulds generally produce several mycotoxins
and synergizers, which are not toxic themselves, but enhance the toxicity of some mycotoxins
174 . It is also stressed that repeated low concentration exposure of airborne mycotoxins
would be very difficult to diagnose.
When trying to predict which biologically active compounds of microfungal origin may be present
in water-damaged buildings - at least five problems have to be addressed:
• Most secondary metabolites and mycotoxins are species specific making identification of
isolates to the species level extremely important. Changes in taxonomy including introduction
of new species and synonomisation of others have further complicated this
work 62,175 .
• False positive findings of mycotoxins are often common from laboratories which use insufficiently
specific methods, or which are not experienced in mycotoxin analysis and the
large number of interfering compounds produced by moulds 62 .
• Even in fungal extracts of species, which have been extensively studied for their metabolites
as e.g. Aspergillus flavus, A. fumigatus, and Fusarium graminearum, unknown biologically
active metabolites are still present 69 .
• A large number of the secondary metabolites described in the literature have been tested
in a very few assays, and extremely few compounds have been tested in full animal studies.
The latter method is unfortunately often the only way of finding defects in the offspring
or reveal metabolites which are activated in special organs such as liver or kidney
144,176 . For exposure assessment even fewer metabolites have been tested in inhalation
studies where some metabolites have been magnitudes more potent 177 .
• The produced metabolites vary considerably between media, so the moulds may produce
very different metabolites when growing on building materials 63,178 .
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