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Water is a critical commodity for spacecraft crews, requiring extreme conservation and reclamation strategies. In addition to suppression of the immune system in spaceflight, enhancement of bacterial growth and antimicrobial resistance in weightlessness raise serious concerns regarding microbial contamination of water systems. ...We report on the combination of methods into highly sensitive, rapid technologies for detecting specific target bacteria and assessing their viability in spacecraft water.

To determine the microbiological quality of water for potable and other purposes, there is a need for rapid methods to enumerate viable bacteria. This is of particular importance for the proposed water recovery systems planned for the United States Space Station, in which wastewaters including hygiene water and urine will be reclaimed for potable use. Existing microbiological culture methods are limited by the time taken to obtain results and because it is not possible to detect the total microbial populations by these methods. We have been investigating direct microscopic methods which detect individual bacterial cells. Fluorogenic compounds are used which are taken up by active cells, permitting a direct assessment of physiological activity. The methods are being adapted for use with membrane filtration which permits concentration of small numbers of cells from large volumes of water. Procedures for direct examination of cells growing on surfaces as biofilms have also been devised.

Although resistant bacteria may colonize spacecraft water systems, multiple treatment barriers should provide adequate control of these contaminants.

Thus, disinfection and maintenance of spacecraft water systems should take into account the difficulties of controlling attached bacteria, which are commonly encountered in earth-based systems.

Drinking water aboard spacecraft and on earth must be monitored to ensure that harmful bacteria are absent. NASA needs rapid methods for this purpose, to avoid possible launch delays and limit potential water-related health risks aboard spacecraft on orbit. ...NASA needs rapid methods for this purpose, to avoid possible launch delays and limit potential water-related health risks aboard spacecraft on orbit. Determination of bacterial viability after exposure to disinfection has significant health importance since oxidatively injured pathogenic bacteria have been shown to retain their virulence. ...Methods such as those described are candidates for future spacecraft use by NASA, and will also be useful in the microbiological examination of water and food on earth.

A number of microbiological issues are of critical importance to crew health and system performance in spacecraft water systems. This presentation will review an array of these concerns which include factors that influence water treatment and disinfection in spaceflight such as biofilm formation and the physiological responses of bacteria in clean water systems.

Experiments were done to examine the sensitivity of various waterborne bacteria from iodinated systems to iodine, and their subsequent recovery and growth, because this halogen is used as a disinfectant in potable water systems on US manned space vehicles. A Pseudomonas aeruginosa isolated from a commercial iodine product was least sensitive when grown in reagent-grade water or phosphate buffered water (PBW) and most sensitive when cultivated on mineral salts medium supplemented with low levels of glucose and glutamate or Brain Heart Infusion (BHI) broth. However, a P. cepacia strain was most sensitive when grown on BHI broth. Isolates from an iodinated potable water system were less sensitive to iodine than Ps-4 while a clinical isolate exhibited intermediate sensitivity. Bacteria including Ps-4 generally recovered and grew in PBW at greater rates than uniodinated controls.

A flex hose assembly containing aqueous coolant from the International Space Station (ISS) Internal Active Thermal Control System (IATCS) consisting of a 2 foot section of Teflon hose and quick disconnects (QDs) and a Special Performance Checkout Unit (SPCU) heat exchanger containing separate channels of IATCS coolant and iodinated water used to cool spacesuits and Extravehicular Mobility Units (EMUs) were returned for destructive analyses on Shuttle return to flight mission STS-114. The original aqueous IATCS coolant used in Node 1, the Laboratory Module, and the Airlock consisted of water, borate (pH buffer), phosphate (corrosion control), and silver sulfate (microbiological control) at a pH of 9.5 ± 0.5.