EcAMSat spaceflight measurements of the role of σs in antibiotic resistance of stationary phase Escherichia coli in microgravity. (February 2020)

• Record Type: Journal Article
• Authors: Padgen, Michael R.; Lera, Matthew P.; Parra, Macarena P.; Ricco, Antonio J.; Chin, Matthew; Chinn, Tori N.; Cohen, Aaron; Friedericks, Charlie R.; Henschke, Michael B.; Snyder, Timothy V.; Spremo, Stevan M.; Wang, Jing-Hung; Matin, A.C.
• Is Part Of: Life sciences in space research. Volume 24(2020)
• Page Start: 18
• Page End: 24
• Publication Date: 2020-02
• Subjects: EcAMSat -- Spaceflight -- Microgravity -- Cubesat -- Antibiotic resistance -- E. coli; Space biology -- Periodicals; 571.0919
• DOI: 10.1016/j.lssr.2019.10.007
• Languages: English
• ISSNs: 2214-5524

Abstract

Abstract: We report the results of the EcAMSat ( Escherichia coli Antimicrobial Satellite) autonomous space flight experiment, investigating the role of σ s in the development of antibiotic resistance in uropathogenic E. coli (UPEC) in microgravity (µ-g ). The presence of σ s, encoded by the rpoS gene, has been shown to increase antibiotic resistance in Earth gravity, but it was unknown if this effect occurs in µ-g . Two strains, wildtype (WT) UPEC and its isogenic Δ rpoS mutant, were grown to stationary phase aboard EcAMSat, an 11-kg small satellite, and in a parallel ground-based control experiment; cell growth rates for the two strains were found to be unaltered by µ-g . After starvation for over 24 h, stationary-phase cells were incubated with three doses of gentamicin (Gm), a common treatment for urinary tract infections (which have been reported in astronauts). Cellular metabolic activity was measured optically using the redox-based indicator alamarBlue (aB): both strains exhibited slower metabolism in µ-g, consistent with results from previous smallsat missions. The results also showed that µ-g did not enhance UPEC resistance to Gm; in fact, both strains were more susceptible to Gm in µ-g . It was also found, via a second ground-control experiment, that multi-week storage in the payload hardware stressed the cells, potentially obscuring small differential effects of the antibiotic between WT and mutant and/or between µ-g and ground. Overall, results showed that the ∆ rpoS mutant was 34–37% less metabolically active than the WT for four different sets of conditions: ground without Gm, ground with Gm; µ-g without Gm, µ-g with Gm. We conclude therefore that the rpoS gene and its downstream products are important therapeutic targets for treating bacterial infections in space, much as they are on the ground.