Abstract

Biofilm Forming Multi-Resistant Pathogens on the ISS

Elisabeth Grohmann, Professor, Beuth University of Applied Sciences Berlin

The International Space Station (ISS) is a closed habitat in a uniquely extreme and hostile environment. Due to these special conditions, the human microflora can undergo unusual changes and may represent health risks for the crew. To address this problem, we investigated the antimicrobial activity of a novel surface coating consisting of micro-galvanic elements of silver and ruthenium along with examining the activity of a conventional silver coating. The antimicrobial materials and respective control materials were exposed on the ISS for different time-periods. On all materials, surviving bacteria were dominated by Gram-positives and among those by Staphylococcus, Bacillus and Enterococcus spp. The novel antimicrobial surface coating AGXX proved to be highly effective. Microbial diversity increased with increasing exposure time on all three materials. The number of recovered bacteria decreased significantly from the uncoated control material to the silver coating to AGXX. Most Gram-positive pathogenic isolates were multidrug resistant. Average resistance transfer frequency was 10-5 transconjugants/recipient. Importantly, no serious human pathogens such as MRSA or vancomycin-resistant Enterococci (VRE) were found on any surface. Thus, the infection risk for the crew is low, especially when antimicrobials such as AGXX are applied to surfaces prone to microbial contamination.