Non-Toxin-Producing Bacillus cereus Strains Belonging to the B. anthracis Clade Isolated from the International Space Station

ABSTRACT: In an ongoing Microbial Observatory investigation of the International Space Station (ISS), 11 Bacillus strains (2 from the Kibo Japanese experimental module, 4 from the U.S. segment, and 5 from the Russian module) were isolated and their whole genomes were sequenced. A comparative analysis of the 16S rRNA gene sequences of these isolates showed the highest similarity (>99%) to the Bacillus anthracis-B. cereus-B. thuringiensis group. The fatty acid composition, polar lipid profile, peptidoglycan type, and matrix-assisted laser desorption ionization-time of flight profiles were consistent with the B. cereus sensu lato group. The phenotypic traits such as motile rods, enterotoxin production, lack of capsule, and resistance to gamma phage/penicillin observed in ISS isolates were not characteristics of B. anthracis. Whole-genome sequence characterizations showed that ISS strains had the plcR non-B. anthracis ancestral "C" allele and lacked anthrax toxin-encoding plasmids pXO1 and pXO2, excluding their identification as B. anthracis. The genetic identities of all 11 ISS isolates characterized via gyrB analyses arbitrarily identified them as members of the B. cereus group, but traditional DNA-DNA hybridization (DDH) showed that the ISS isolates are similar to B. anthracis (88% to 90%) but distant from the B. cereus (42%) and B. thuringiensis (48%) type strains. The DDH results were supported by average nucleotide identity (>98.5%) and digital DDH (>86%) analyses. However, the collective phenotypic traits and genomic evidence were the reasons to exclude the ISS isolates from B. anthracis. Nevertheless, multilocus sequence typing and whole-genome single nucleotide polymorphism analyses placed these isolates in a clade that is distinct from previously described members of the B. cereus sensu lato group but closely related to B. anthracis. IMPORTANCE: The International Space Station Microbial Observatory (Microbial Tracking-1) study is generating a microbial census of the space station's surfaces and atmosphere by using advanced molecular microbial community analysis techniques supported by traditional culture-based methods and modern bioinformatic computational modeling. This approach will lead to long-term, multigenerational studies of microbial population dynamics in a closed environment and address key questions, including whether microgravity influences the evolution and genetic modification pathogenic (B. anthracis), food poisoning (B. cereus), and biotechnologically useful (B. thuringiensis) microorganisms; their presence in a closed system such as the ISS might be a concern for the health of crew members. A detailed characterization of these potential pathogens would lead to the development of suitable countermeasures that are needed for long-term future missions and a better understanding of microorganisms associated with space missions

Draft Genome Sequences from a Novel Clade of <i>Bacillus cereus Sensu Lato </i>Strains, Isolated from the International Space Station

The draft genome sequences of six Bacillus strains, isolated from the International Space Station and belonging to the Bacillus anthracis-B. cereus-B. thuringiensis group, are presented here. These strains were isolated from the Japanese Experiment Module (one strain), U.S. Harmony Node 2 (three strains), and Russian Segment Zvezda Module (two strains)

Fecal Microbiota Composition and Frailty

The relationship between fecal microbiota composition and frailty in the elderly was studied. Fecal samples from volunteers with high frailty scores showed a significant reduction in the number of lactobacilli (26-fold). At much higher population levels, both the Bacteroides/Prevotella (threefold) and the Faecalibacterium prausnitzii (fourfold) groups showed a significant reduction in percentage of total number of hybridizable bacteria in the elderly with high frailty scores. In contrast to this, the number of Enterobacteriaceae was significantly higher (sevenfold) in samples from very frail volunteers

Microbial detection and monitoring in advanced life support systems like the international space station

Potentially pathogenic microbes and so-called technophiles may form a serious threat in advanced life support systems, such as the International Space Station (ISS). They not only pose a threat to the health of the crew, but also to the technical equipment and materials of the space station. The development of fast and easy to use molecular detection and quantification methods for application in manned spacecraft is therefore desirable and may also be valuable for applications on Earth. In this paper we present the preliminary results of the SAMPLE experiment in which we performed molecular microbial analysis on environmental samples of the ISS as part of an ESA-MAP project

PCR oligonucleotide primers used in this study.

<p>Bold: T7 and UP extension, respectively.</p><p>Abbreviations: FAM, carboxyfluorescein; CY, cyanine; BHQ, Black Hole Quencher.</p

Overview of isolate characteristics using several methodologies.

<p>Abbreviations: +, positive; v, variable; (+) or (−), weak reaction; −, negative; S, susceptible; R, resistant; ND, not determined. Symbols for colony morphology indicate similarity and differences. All data were obtained in this study, except data for <i>B. cereus</i>, <i>B. anthracis</i>, <i>B. thuringiensis</i> and <i>B. mycoides</i> that were compiled <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0098871#pone.0098871-Logan1" target="_blank">[21]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0098871#pone.0098871-Logan2" target="_blank">[22]</a>.</p><p>*Gamma phage susceptibility is not truly specific for <i>B. anthracis</i><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0098871#pone.0098871-Turnbull1" target="_blank">[32]</a>.</p

16S rDNA sequence signature comparison of isolates according to the Sacchi et[31] type scheme.

<p>Abbreviations: R, A or G nucleotide; Y, C or T nucleotide; M, A or C nucleotide; W, A or T nucleotide. Nucleotides between brackets indicate a weak double signal of that nucleotide at that position.</p