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Evaluation of the Biocidal Efficacy of Different Forms of Silver Against Cupriavidus (formerly Wautersia) Species BacteriaContingency Water Containers (CWCs) are used to store potable and technical water that is transferred to the International Space Station (ISS) from the Shuttle orbiter vehicles. When CWCs are filled, water from the orbiter galley is passed through an ion exchange/activated carbon cartridge that removes the residual iodine biocide used on Shuttle before silver biocide is added. Removal of iodine and addition of silver is necessary to inhibit microbial growth inside CWCs and maintain compatibility with the water systems in the Russian segment of ISS. As part of nominal water transfer activities, crewmembers collect samples from several CWCs for postflight analysis. Results from the analysis of water transfer samples collected during the docked phases of STS-118/13A.1 and STS-120/10A showed that several of the CWCs contained up to 10(exp 4) CFU/mL of bacteria despite the fact that the silver concentrations in the CWCs were within acceptable limits. The samples contained pure cultures of a single bacteria, a Cupriavidus (formerly Wautersia) species that has been shown to be resistant to metallic biocides. As part of the investigation into the cause and remediation of the bacterial contamination in these CWCs, ground studies were initiated to evaluate the resistance of the Cupriavidus species to the silver biocides used on ISS and to determine the minimum effective concentration for the different forms of silver present in the biocides. The initial findings from those experiments are discussed herein.
Document ID
20090001911
Document Type
Conference Paper
Authors
Gazda, Daniel B.
(Wyle Integrated Science and Engineering Group Houston, TX, United States)
Schultz, John R.
(Wyle Integrated Science and Engineering Group Houston, TX, United States)
Wong, Wing
(Enterprise Advisory Services, Inc. Houston, TX, United States)
Algate, Michelle T.
(Enterprise Advisory Services, Inc. Houston, TX, United States)
Bryant, Becky
(Enterprise Advisory Services, Inc. Houston, TX, United States)
Castro, Victoria A.
(Enterprise Advisory Services, Inc. Houston, TX, United States)
Date Acquired
August 24, 2013
Publication Date
January 1, 2009
Subject Category
Man/System Technology And Life Support
Meeting Information
39th International Conference on Environmental Systems(Savannah, GA)
Distribution Limits
Public
Copyright
Other
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