the potential sources of microbial contamination and give
insight into the causes of health-related microbial
contamination issues such as “sick building syndrome.”
SPACE BENEFITS
Knowing the microorganisms that the crew encounter is
crucial in assessing the health risks of the crew and
performance of the spacecraft systems. By studying the
types of organisms and the change in this ecosystem over
time, preventative and disinfection regiments are
developed to mitigate the accumulation of medically
significant organisms or microorganisms that foul filters or
degrade components of the spacecraft.
RESULTS
For the SWAB flight experiment, it was hypothesized that
environmental analysis using non-culture-based
technologies would reveal microorganisms, allergens, and
microbial toxins not previously reported in spacecraft,
allowing for a more complete health assessment. Key
findings during this experiment included: Sample analyses
using the culture-based and advanced molecular
methodology, which provided similar results, indicating the
current monitoring methods are not “missing” medically
significant bacteria and fungi. Dust samples taken from the
HEPA air filters identified 17 different microbial mold
species, most commonly P. chrysogenum and A. pullulans. Other opportunistic pathogens were
also detected including a particularly high concentration of A. flavus and A. niger. Fortunately,
to date there have been no known health effects from mold as a result of living aboard the ISS
(Vesper 2008). Molecular techniques have tremendous potential for microbial monitoring;
however, sample preparation and data analysis present challenges for spaceflight hardware.
Results indicate that some molecular techniques, such as denaturing gradient gel
electrophoresis (DGGE), can be much less sensitive than culture-based methods, and More
sensitive molecular techniques, such as quantitative polymerase chain reaction (QPCR), were
able to identify viral DNA from ISS environments, suggesting potential transfer of the organism
between crew members.
PUBLICATION(S)
Vesper SJ, Wong W, Kuo CM, Pierson DL. Mold species in dust from the International Space
Station identified and quantified by mold-specific quantitative PCR. Research in Microbiology.
July 2008;159(6):432-435. doi: 10.1016/j.resmic.2008.06.001.
This investigation is complete; however additional results are pending publication.
ISS010E11563 - An example of
contamination that has developed on
one of the interior panels aboard ISS.
This image shows how contamination
can form on interior ISS surfaces.
Crews have weekly sessions to clean
ISS surfaces. SWAB will help us
understand the microbes involved in
contamination and how to deal with
them.