Polymicrobial Biofilm Growth and Control during Spaceflight (Bacterial Adhesion and Corrosion)

Polymicrobial Biofilm Growth and Control during Spaceflight (Bacterial Adhesion and Corrosion) explores the formation under microgravity conditions of multi-species biofilms, which may behave differently from single-species biofilms. This investigation identifies the bacterial genes used during biofilm growth, examines whether these biofilms can corrode stainless steel, and evaluates the effectiveness of a silver-based disinfectant. The microorganisms in biofilms can become resistant to traditional cleaning chemicals, leading to contamination of water treatment systems, damage to equipment, and potential health risks to astronauts.

Delivery of partial reflight investigation to the International Space Station (ISS) via the SpaceX-29 Commercial Resupply Service mission in November, 2023.

Bacteria and other microorganisms have been shown to grow as biofilm communities in the microgravity environment of spaceflight. Organisms within biofilms are often resistant to traditional antimicrobial chemicals and can foul water treatment filters, resulting in potential risks to astronaut health. The biofilms on the International Space Station (ISS) consist of many species, but previous studies have only tested single-species biofilms. There is growing evidence that mixed-species biofilms behave differently from single-species biofilms, and it is anticipated that this phenomenon will occur in the microgravity environment of the ISS. The Polymicrobial Biofilm Growth and Control During Spaceflight (Bacterial Adhesion and Corrosion) study investigates the structure and gene expression of two-species mixed biofilms formed in microgravity on stainless steel similar to that used to construct the ISS Environmental Controls and Life Support Systems (ECLSS). The bacteria chosen for this experiment are two common biofilm-forming species: a previously flown strain of Pseudomonas aeruginosa (PAO1) and a strain of Escherichia coli (F11) that has been associated with bladder infections. These studies explore the formation of mixed biofilms under microgravity conditions, the effectiveness of biofilm control using a silver-based disinfection method, the bacterial genes that are used, and whether microgravity-grown mixed biofilms cause corrosion on stainless steel. Results from this investigation can provide researchers with a better understanding of biofilm architecture, mechanisms used by microorganisms (gene-expression) in extreme environments, and the effectiveness of disinfection measures.

The risks posed by biofilm fouling of spacecraft systems are expected to increase with increased duration of missions. Biofilm formation reported for water systems on the space station presents health risks to crew members, and biofilms affect the integrity and function of the materials on which they form. This investigation could provide insight into better ways to control and remove resistant biofilms, contributing to the success of future long-duration spaceflights.

Biofilms, which enable bacteria to survive environmental stresses, disinfectants, and antibiotic treatments, can serve as a reservoir for infectious organisms and promote corrosion of materials on Earth as well as in space. This investigation could improve understanding of multispecies biofilm architecture and gene expression and support development of effective disinfection in extreme environments on Earth.

Space Station Research Explorer