Abstract
In light of an upcoming new era of human expansion in the universe, such as future space travel to Mars, the microbiome of the closed space environment needs to be examined thoroughly to identify the types of microorganisms that can accumulate in this unique environment, how long they persist and survive and their impact on human health and spacecraft infrastructure. As part of this NASA initiative, the viable microbial communities on ISS surfaces from eight different locations over three flight missions, spanning 14 months, were characterized using culture-based techniques, qPCR and amplicon sequencing of the 16S rRNA gene and internal transcribed spacer region using the Illumina platform. Across three flight samplings, K. pneumoniaereads, an opportunistic BSL-2 pathogen, were retrieved during Flight 1 and successively its reads persisted in Flight 2. Subsequently, in Flight 3, most of the locations were inflicted with the presence of this opportunistic pathogen. Other noticeable opportunistic pathogens of all flights were A. baumannii, E. cloacae, S. enterica,and S. sonneias well as some fungi. None of the pathogenic fungi were persistent in any of the locations sampled.