Task Efficacy of Antimicrobials on Bacteria Cultured in a Spaceflight Analog (Completed)
Last Published:  11/23/20 11:55:12 AM (Central)
Short Title: Antimicrobial-Pilot
Responsible HRP Element: Human Health Countermeasures
Collaborating Org(s):
Space Human Factors Habitability (SHFH) Element
Funding Status: Completed - Task completed and produced a deliverable
Procurement Mechanism(s):

 The NASA Rotating Wall Vessel (RWV) culture system has been successfully used as a spaceflight culture analogue to identify potential alterations in several key microbial characteristics, such as virulence and gene regulation, in response to spaceflight culture. This study investigated the response of three medically significant microorganisms grown in the RWV to antibiotics currently used aboard the International Space Station. Generally, the organisms did not display significant differences when compared to appropriate controls, however, a few interesting exceptions were noted. Evaluation of Salmonella enterica Typhimurium indicated alterations in antibiotic sensitivity to azithromycin, which interferes with protein synthesis, but only at one concentration when longer exposure times were adopted. Interestingly, Pseudomonas aeruginosa displayed reproducible changes in resistance to azithromycin depending on the level of fluid shear, which was modulated through the incorporation of beads added to the RWV; suggesting a more complex shear associated mechanism. The methicillin resistant Staphylococcus aureus N315 strain also demonstrated an enhanced resistance under microgravity-analogue culture conditions to levofloxacin, a DNA gyrase inhibitor. For both S. aureus and P. aeruginosa, the enhanced antibiotic resistance in microgravity-analogue conditions could most likely be attributed to enhanced extracellular polysaccharide production. Collectively, these findings suggest potential alterations in antibiotic efficacy during spaceflight and indicate that future studies on the antibiotic response require additional basic research using the RWV and/or true spaceflight. However, while this analogue has reinforced these potential alterations, the results suggest the best approach for applied forward work is evaluating an in vivo system during spaceflight, including human and rodent studies.

This study provides preliminary data indicating changes in antimicrobial medication efficacy in a ground-based spaceflight analog.  As a result, future studies have been incorporated into the research plan to further characterize the changes in efficacy during spaceflight.

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