Untersuchungen zum Vorkommen und zur gesundheitlichen ...

4.6 Summary
Diversity
The results of the study show, that the different damp building materials contain
different and diverse actinomycete communities in high concentrations (range 1,8
x10 4 -7,6 x10 7 CFU/g).
Streptomyces, Amycolatopsis, Nocardiopsis, Nocardia, Pseudonocardia,
Saccharopolyspora und Promicromonospora were the most commonly detected
genera, with representatives of the genus Streptomyces beeing most abundant.
Because these genera were found in most samples, it can be assumed, that they are
typical for humidity damaged materials in indoor environments. Nevertheless, in one
sample (loam rendering) none of the above mentioned genera was detected and not
all genera were present in all samples.
The results of this study show no clear correlation between the genus/species
composition and the type of damp building material, although such a differentiation in
regard to nutrient composition, humidity, pH-value, micro- and surface structures of
the materials in addition to the air humidity and the temperature is reported in the
literature.
The number of samples studied is too small to allow for general and statistically
significant conclusions with regard to the different materials. Furthermore, unusual
results found for one material sample may have masked a possible material effect.
Methods:
A higher diversity of actinomycetes was found with molecular methods compared to
culture based methods. For this reason the application of both, cultivation-dependent
and cultivation-independent methods for the study of the diversity of actinomycetes in
humidity damaged materials is highly recommended.
The analyses of the 16S rRNA gene sequences of the isolates in the course of the
cultivation-based approach allowed a more rapid and precise allocation at the genus
or group level, than a morphological and/or chemotaxonomic characterization. For
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