This is a good study to remind us that while we test for fungal species with ERMI/HERTSMI2, we need to remember that there is a complex microbiome of many species competing for resources, otherwise known as secreting their toxins into the environment to get a competitive advantage for those resources. Moist cellulose!! Yummy!! We mere humans are often collateral damage in microbiological warfare! It’s a dirty and complex game.
We really need to get some good studies on the specific toxins most likely to cause problems from the buildings themselves. At the moment, we can test for about 9 toxins in the urine from 2 different labs. Wouldn’t it be great to have profiles of what can be found in the buildings themselves to help guide us and prove (for legal/liability/disability & other perspectives) the association/causality of the relationship with the building and the disease! More work is needed!
Toxic microbial secondary metabolites have been proposed to be related to adverse health effects observed in moisture-damaged buildings. Initial steps in assessing the actual risk include the characterization of the exposure. In our study, we applied a multi-analyte tandem mass spectrometry-based methodology on sample materials of severely moisture-damaged homes, aiming to qualitatively and quantitatively describe the variety of microbial metabolites occurring in building materials and different dust sample types. From 69 indoor samples, all were positive for at least one of the 186 analytes targeted and as many as 33 different microbial metabolites were found. For the first time, the presence of toxic bacterial metabolites and their co-occurrence with mycotoxins were shown for indoor samples. The bacterial compounds monactin, nonactin, staurosporin and valinomycin were exclusively detected in building materials from moist structures, while chloramphenicol was particularly prevalent in house dusts, including settled airborne dust. These bacterial metabolites are highly bioactive compounds produced by Streptomyces spp., a group of microbes that is considered a moisture damage indicator in indoor environments. We show that toxic bacterial metabolites need to be considered as being part of very complex and diverse microbial exposures in ‘moldy’ buildings.
Bacterial toxins co-occur with mycotoxins in moisture-damaged indoor environments. These compounds are measurable also in settled airborne dust, indicating that inhalation exposure takes place. In attempts to characterize exposures to microbial metabolites not only mycotoxins but also bacterial metabolites have to be targeted by the analytical methods applied. We recommend including analysis of samples of outdoor air in the course of future indoor assessments, in an effort to better understand the outdoor contribution to the indoor presence of microbial toxins. There is a need for a sound risk assessment concerning the exposure to indoor microbial toxins at concentrations detectable in moisture-damaged indoor environments.