EcAMSat spaceflight measurements of the role of σ in antibiotic resistance of stationary phase Escherichia coli in microgravity.

We report the results of the EcAMSat (Escherichia coli Antimicrobial Satellite) autonomous space flight experiment, investigating the role of σ in the development of antibiotic resistance in uropathogenic E. coli (UPEC) in microgravity (µ-g). The presence of σ, 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.

Payload hardware and experimental protocol development to enable future testing of the effect of space microgravity on the resistance to gentamicin of uropathogenic Escherichia coli and its σ-deficient mutant.

Human immune response is compromised and bacteria can become more antibiotic resistant in space microgravity (MG). We report that under low-shear modeled microgravity (LSMMG), stationary-phase uropathogenic Escherichia coli (UPEC) become more resistant to gentamicin (Gm), and that this increase is dependent on the presence of σ (a transcription regulator encoded by the rpoS gene). UPEC causes urinary tract infections (UTIs), reported to afflict astronauts; Gm is a standard treatment, so these findings could impact astronaut health.