Effect of spaceflight on Pseudomonas aeruginosa final cell density is modulated by nutrient and oxygen availability

Wooseong Kim, Farah K Tengra, Jasmine Shong, Nicholas Marchand, Hon Kit Chan, Zachary Young, Ravindra C Pangule, Macarena Parra, Jonathan S Dordick, Joel L Plawsky, Cynthia H Collins

Abundant populations of bacteria have been observed on Mir and the International Space Station. While some experiments have shown that bacteria cultured during spaceflight exhibit a range of potentially troublesome characteristics, including increases in growth, antibiotic resistance and virulence, other studies have shown minimal differences when cells were cultured during spaceflight or on Earth. Although the final cell density of bacteria grown during spaceflight has been reported for several species, we are not yet able to predict how different microorganisms will respond to the microgravity environment. In order to build our understanding of how spaceflight affects bacterial final cell densities, additional studies are needed to determine whether the observed differences are due to varied methods, experimental conditions, or organism specific responses.