CHARACTERIZATION OF STAPHYLOCOCCUS ISOLATES FROM THE BED REST STUDY AGBRESA

Abstract

Over 30 years, the Space Shuttle program provided valuable insights into the microbiology of manned spaceflight regarding human health and technical applications [1, 2]. During spaceflight, the microgravity environment alters the human body physiology which leads to a redistribution of tissue fluids [3]. Physiological properties of the skin are directly correlated with the abundance and diversity of the local skin microbiome [4]. Bacterial adaptation towards microgravity which led to an increased virulence are described in literature [1]. The characterization of human skin associated bacteria, such as Staphylococci are crucial to estimate the risk emerging from the skin microbiome towards the safety of the astronaut and the vessel. In this thesis, five Staphylococcus isolates from the human skin were identified by multiple methods and their properties regarding growth under stress, desiccation tolerance, antibiotic resistance, biofilm formation and pigmentation were examined. Four out of five skin isolates were viable after 14 days of desiccation. While antibiotic resistance was observed sporadically, the properties towards biofilm formation showed to be the primary virulence factor of the isolates in this examination. Carotenoid-based pigmentation was observed in three out of five skin isolates. These results are showing properties of the isolates which cannot exclude a threat to the successful completion of manned space missions. This thesis can be used as starting point for subsequent experiments to establish a uniform method for the evaluation of the skin microbiome towards manned spaceflight. For example, the protection by the immune system and technical counter measurements against the isolates properties to interfere manned space missions can be included in further examinations.