Life in space: exploring the evolutionary co-adaptation of microbes on the ISS
Fall 2020 Graduate Student Award in Pathogenic and Commensal Organisms
Microbes are not only present on earth but are also found in outer space. Since humans harbor large quantities of microbes, astronauts are an important source of bacterial contamination in space. Astronauts undergo severe immune dysregulation during space flight making virulent mutations of their normal flora a primary concern. To prevent infection, the International Space Station has used iodine as the primary biocide. However, due to thyroid issues they are proposing a switch to silver. The Integrated Mathematical Medical Model predicts that dental emergencies will be one of the top five conditions impacting future mission objectives. Currently the phenotypes of these organisms on earth are well studied and the treatment strategies are more predictable, but current data may not be comparable to long-term space flight. We propose using ground-based High Aspect Rotating Vessels (HARVs) to simulate microgravity and carry out experimental evolution studies over ~100-days. We will evaluate the evolutionary response of Streptococcus mutans (an agent of dental cavities) grown in biofilm communities. Because Streptococcal species reside in the oral cavity, they will frequently encounter silver through the consumption of water and rehydrated foods on the ISS. Due to this, we hypothesize that S. mutans grown in presence of silver long-term, will evolve resistance mechanisms influenced by the desire to form biofilms. Moreover, as metal resistance is often accompanied by antibiotic resistance, we also hypothesize that these pathogens will evolve increased virulence, become multi-drug resistant and increase the incidence rate of cavities in space.
