Unravelling the microbial fitness and the acquired co-resistances towards environmental extremes of vancomycin resistant enterococci

Abstract

The COVID-19 pandemic displayed how vital international cooperation and preparedness are in a crisis with over 4 million deaths worldwide. Now is the opportunity to prevent future microbial pandemics and respond with awareness, knowledge and preparedness. Antimicrobial resistances (AMR) spread globally via international travel and supply chains and there is an essential need for detecting future pandemic threats like AMR. The WHO listed vancomycin-resistant enterococci (VRE) with high priority on the global priority list of antibiotic resistant bacteria. As a cause of endemic hospital outbreaks worldwide, VRE emerged as nosocomial pathogens which are life threatening for immunosuppressed patients. Weakened immune functions are also a health issue for astronauts exposed to various stressors on long-term space missions. Therefore, VRE can become a threat whether on Earth or in space. To prevent VRE infections and guarantee the health of the crew members it is important to understand the influence of microgravity on the development of antibiotic resistances. Hence, antibiotic resistances of clinical isolates of sensible, low-level and high-level vancomycin resistant enterococci were investigated after simulated microgravity. Therefore, the minimal inhibitory concentration (MIC) was determined before and after simulated microgravity by using clinorotation. Additionally, stress tests for characterization under extreme environmental conditions were performed. As a result, the majority of the VRE isolates showed no change in their resistance behavior after simulated microgravity. Furthermore, as one of the extreme environmental conditions, the isolates showed an increased tolerance to desiccation after simulated microgravity. The fact that the VRE resistance behavior was similar under simulated microgravity to the control (normal terrestrial 1 x g) stresses importance under both conditions and allows for similar containment and therapy strategies both, on Earth and in space. To estimate the risk of VRE and their role in an upcoming pandemic of drug resistant infections it is essential to investigate VRE fitness and narrow down methods against the arising challenge of antibiotic resistant bacteria. Moreover, analysis of multistress factors of VRE and research of co-resistance towards environmental extremes and space conditions will improve the understanding how to fight drug resistant bacteria and, therefore, minimize healthcare-associated infections worldwide.