With the advent of long-term human habitation in space and on the moon, understanding how the built environment microbiome of space habitats differs from Earth habitats, and how microbes survive, proliferate and spread in space conditions, is becoming more important. The microbial tracking mission series has been monitoring the microbiome of the International Space Station (ISS) for almost a decade. During this mission series, six unique strains of Gram-stain-positive bacteria, including two spore-forming and three non-spore-forming species, were isolated from the environmental surfaces of the ISS. The analysis of their 16S rRNA gene sequences revealed > 99% similarities with previously described bacterial species. To further explore their phylogenetic affiliation, whole genome sequencing was undertaken. For all strains, the gyrB gene exhibited < 93% similarity with closely related species, which proved effective in categorizing these ISS strains as novel species. Average nucleotide identity and digital DNA–DNA hybridization values, when compared to any known bacterial species, were < 94% and <50% respectively for all species described here. Traditional biochemical tests, fatty acid profiling, polar lipid, and cell wall composition analyses were performed to generate phenotypic characterization of these ISS strains. A study of the shotgun metagenomic reads from the ISS samples, from which the novel species were isolated, showed that only 0.1% of the total reads mapped to the novel species, supporting the idea that these novel species are rare in the ISS environments. In-depth annotation of the genomes unveiled a variety of genes linked to amino acid and derivative synthesis, carbohydrate metabolism, cofactors, vitamins, prosthetic groups, pigments, and protein metabolism. Further analysis of these ISS-isolated organisms revealed that, on average, they contain 46 genes associated with virulence, disease, and defense. The main predicted functions of these genes are: conferring resistance to antibiotics and toxic compounds, and enabling invasion and intracellular resistance. After conducting antiSMASH analysis, it was found that there are roughly 16 cluster types across the six strains, including β-lactone and type III polyketide synthase (T3PKS) clusters. Based on these multi-faceted taxonomic methods, it was concluded that these six ISS strains represent five novel species, which we propose to name as follows:Arthrobacter burdickiiIIF3SC-B10^T(= NRRL B-65660^T= DSM 115933^T),Leifsonia virtsiiF6_8S_P_1A^T(= NRRL B-65661^T= DSM 115931^T),Leifsonia williamsiiF6_8S_P_1B^T(= NRRL B-65662^T= DSM 115932^T),Paenibacillus vandeheiiF6_3S_P_1C^T(= NRRL B-65663^T= DSM 115940^T), andSporosarcina highlanderaeF6_3S_P_2^T(= NRRL B-65664^T= DSM 115943^T). Identifying and characterizing the genomes and phenotypes of novel microbes found in space habitats, like those explored in this study, is integral for expanding our genomic databases of space-relevant microbes. This approach offers the only reliable method to determine species composition, track microbial dispersion, and anticipate potential threats to human health from monitoring microbes on the surfaces and equipment within space habitats. By unraveling these microbial mysteries, we take a crucial step towards ensuring the safety and success of future space missions.

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) infection is one of the global healthcare concerns. Here, we report the phenotypic and genotypic characterization of a novel multi-host Staphylococcus phage RuSa1, isolated from wastewater samples derived from a spotted sambar deer (Rusa unicolor) enclosure located at Mangalore, India. Clinical MRSA strains (n = 18) susceptible to RuSa1 were genetically and phenotypically diverse as determined by DNA fingerprinting and in vitro culture assays. RuSa1 displayed a latent period and burst size of 10 min and 50 PFU, respectively, and exhibited efficient biofilm removal activities against S. aureus ATCC BAA-44. The phage exhibited moderate UV stability (3 min) and high titre at 4–37 °C and pH 5‒9. RuSa1 possessed a linear double-stranded genomic DNA with a length of 140 kb. The genome contained 30.18% GC composition and shared 82.0‒94.9% sequence similarity with eleven authentic species of Kayvirus recognized by the International Committee on Taxonomy of Viruses based on VIRIDIC analysis. RuSa1 established distinct phyletic lineage in the maximum likelihood phylogenetic analysis of DNA encoding structural proteins and lacked genes that confer lysogeny. Based on the genotypic, phylogenetic and phenotypic data, RuSa1 is proposed to be a lytic phage and a new species of Kayvirus with a potential therapeutic ability against staphylococcal infections.

A polyphasic taxonomic approach was used to characterize a Gram-stain-negative bacterium, designated strain CC-CFT640T, isolated from vineyard soil sampled in Taiwan. Cells of strain CC-CFT640T were aerobic, non-motile, nitrate-reducing rods. Test results were positive for catalase, oxidase and proteinase activities. Optimal growth occurred at 30 °С and pH 7. Strain CC-CFT640T showed highest 16S rRNA gene sequence similarity to members of the genus Enhydrobacter (90.0 %, n=1) followed by Hypericibacter (89.4–90.0 %, n=2), Reyranella (88.8–89.8 %, n=5) and Nitrospirillum (89.2–89.4 %, n=2), and formed a distinct phyletic lineage distantly associated with the clade that predominately accommodated Reynerella species. The DNA G+C composition of the genome (2.1 Mb) was 67.9 mol%. Genes involved in the reduction of nitrate to nitrite, nitric oxide and nitrous oxide were found. In addition, genes encoding dissimilatory nitrate reduction to ammonia, ammonium transport and ammonium assimilation were also detected. Average nucleotide identity values were 73.3 % (n=1), 74.0–74.6 % (n=2), 67.5–68.3 % (n=2) when compared within the type strains of the genera Enhydrobacter , Reyranella and Niveispirillum , respectively. The dominant cellular fatty acids (>5 %) included C16 : 0, iso-C17 : 1 ω10c, C19 : 0 cyclo ω8c, C18 : 1 2-OH and C18 : 1 ω7c/C18 : 1 ω6c. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, three unidentified aminolipids, three unidentified phospholipids and an unidentified aminophospholipid. The major respiratory quinone was ubiquinone 10 and the major polyamine was spermidine. Based on its distinct phylogenetic, phenotypic and chemotaxonomic traits together with results of comparative 16S rRNA gene sequencing, digital DNA–DNA hybridization, average nucleotide identity and phylogenomic placement, strain CC-CFT640T is considered to represent a novel genus and species of the family Rhodospirillaceae , for which the name Vineibacter terrae gen. nov., sp. nov. is proposed. The type strain is CC-CFT640T (=BCRC 81219T=JCM 33507T).

A polyphasic taxonomic approach was used to characterize a Gram-stain-positive fermentative bacterium, designated strain CC-MHH1034^T, isolated from a fermented vegetable residue. Cells of strain CC-MHH1034^T were facultatively anaerobic, non-motile, and non-spore-forming rods, exhibiting positive catalase, oxidase and protease activities. Optimal growth occurred at 30 °С and pH 6.0. Strain CC-MHH1034^T shared the highest 16S rRNA gene sequence similarities with Agrilactobacillus composti (95.9 %) followed by Agrilactobacillus yilanensis (95.1 %) and established a distinct taxonomic lineage associated with these species. Highest orthologous average nucleotide identity (OrthoANI) values were recorded for strain CC-MHH1034^T versus Agrilactobacillus (71.1–71.6 %, n=2) followed by Ligilactobacillus (66.5–66.8 %, n=2), Lactobacillus (64.1–65.8 %, n=4). The mean digital DNA–DNA hybridization (dDDH) value obtained for strain CC-MHH1034^T against Agrilactobacillus was 19.2–19.5 % (n=2). The polar lipid profile consisted of phosphatidylethanolamine, phosphatidylglycerol, two unidentified aminolipids, four unidentified glycolipids, four unidentified phospholipids and one unidentified lipid. The major polyamine was sym-homospermidine and meso-diaminopimelic acid was detected as the cell-wall peptidoglycan. The dominating cellular fatty acids (>5 %) included C_16 : 0, iso-C_15 : 0, anteiso-C_15 : 0 and C_18 : 1  ω9c. Based on its distinct phylogenetic, phenotypic and chemotaxonomic traits together with results of comparative 16S rRNA gene sequence, OrthoANI, dDDH, and the phylogenomic placement, strain CC-MHH1034^T is considered to represent a novel species of the genus Agrilactobacillus , affiliated to the family Lactobacillaceae , for which the name Agrilactobacillus fermenti sp. nov. is proposed. The type strain is CC-MHH1034^T (=BCRC 81220^T=JCM 33476^T).