Stachybotrys chartarum, health hazards related to its presence in both
agricultural and indoor environments
Jean-Denis Bailly
Food Hygiene
Joint Resarch Unit Toxalim
Team Biosynthesis and toxicity of Mycotoxins
National Veterinary School of Toulouse
jd.bailly@envt.fr
Stachybotrys chartarum is a cellulolytic saprophytic hyphomycete of apparent
worldwide distribution. This fungal species has been studied for 50 years due to its
possible implication in human and animal diseases. Indeed, Stachybotrys chartarum is a
potent toxin producer. It has been demonstrated that this fungal species was able to
produce several toxic secondary metabolites among which the most toxic belong to the
family of macrocyclic trichothecenes (Satratoxin G and H, Roridine L2, Verrucarin J).
These compounds are the most potent small molecules protein synthesis inhibitors
known and their toxicity is mainly observed towards tissues with high renewal rate
(epithelia, leukocytes).
Mycotoxins produced by Stachybotrys chartarum were firstly associated with animal
poisoning named Stachybotryotoxicosis. Indeed, the first report of this intoxication was
done in the 1930’s in former USSR and led to the death of many horses. From this date,
several clinical cases were reported worldwide mainly in horses that appear to be the
most sensitive species to these mycotoxins. Stachybotryotoxicosis is characterized in
equines by various disorders, ranging from decreased performances of racehorses to
sudden death in few hours. The classical clinical features are dominated by ulcerations
occurring on mouth and nasal mucosae and hemorrhages in many organs and especially
intestine and lungs. However, intoxications were also observed in other species such as
domestic or wild ruminants.
During the late 90s, Stachybotrys chartarum was subjected to an increased attention due
to its possible implication in human pathologies and specially pulmonary hemorrhages
observed in children in USA and it was also suspected to play a role in the appearance of
sick building syndrome.
Indeed, the strong cellulolytic ability of Stachybotrys allows it growth on water-damaged
building materials such as gypsum board, wallpapers, several building materials… and
Stachybotrys chartarum has been identified as a frequent contaminant of indoor
environments. It raised the hypothesis of a possible exposure of inhabitants to
macrocyclic trichothecenes by inhalation of spores or contaminated dusts and recently,
it was demonstrated the frequent presence of macrocyclic trichothenes in urine from
patients suffering from chronic fatigue syndrome.
Our works aimed to:
-
characterize the nature of Stachybotrys isolates that could contaminate both hay
and indoor environments as well as their toxigenic potential. Indeed, during last
years we noted an increase in equine intoxication with macrocyclic
trichothecenes, possibly related to change in agricultural practices.
-
evaluate the ability of a toxigenic strain to develop and produce macrocyclic
trichothecenes on different indoor materials
-
study the possible aerosolization of these mycotoxin from contaminated
materials to provide new insight into risk assessment related to the presence of
such contaminant.