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Francisella tularensis, the causative agent of tularemia, is capable of causing disease in a multitude of mammals and remains a formidable human pathogen due to a high morbidity, low infectious dose, lack of a FDA approved vaccine, and ease of aerosolization. For these reasons, there is concern over the use of F. tularensis as a biological weapon, and, therefore, it has been classified as a Tier 1 select agent. Fluoroquinolones and aminoglycosides often serve as the first line of defense for treatment of tularemia. However, high levels of resistance to these antibiotics has been observed in gram-negative bacteria in recent years, and naturally derived resistant Francisella strains have been described in the literature. The acquisition of antibiotic resistance, either natural or engineered, presents a challenge for the development of medical countermeasures. In this study, we generated a surrogate panel of antibiotic resistant F. novicida and Live Vaccine Strain (LVS) by selection in the presence of antibiotics and characterized their growth, biofilm capacity, and fitness. These experiments were carried out in an effort to (1) assess the fitness of resistant strains; and (2) identify new targets to investigate for the development of vaccines or therapeutics. All strains exhibited a high level of resistance to either ciprofloxacin or streptomycin, a fluoroquinolone and aminoglycoside, respectively. Whole genome sequencing of this panel revealed both on-pathway and off-pathway mutations, with more mutations arising in LVS. For F. novicida, we observed decreased biofilm formation for all ciprofloxacin resistant strains compared to wild-type, while streptomycin resistant isolates were unaffected in biofilm capacity. The fitness of representative antibiotic resistant strains was assessed in vitro in murine macrophage-like cell lines, and also in vivo in a murine model of pneumonic infection. These experiments revealed that mutations obtained by these methods led to nearly all ciprofloxacin resistant Francisella strains tested being completely attenuated while mild attenuation was observed in streptomycin resistant strains. This study is one of the few to examine the link between acquired antibiotic resistance and fitness in Francisella spp., as well as enable the discovery of new targets for medical countermeasure development.

Purpose. Burkholderia pseudomallei , the tier 1 agent of melioidosis, is a saprophytic microbe that causes endemic infections in tropical regions such as South-East Asia and Northern Australia. It is globally distributed, challenging to diagnose and treat, infectious by several routes including inhalation, and has potential for adversarial use. B. pseudomallei strain MSHR5848 produces two colony variants, smooth (S) and rough (R), which exhibit a divergent range of morphological, biochemical and metabolic phenotypes, and differ in macrophage and animal infectivity. We aimed to characterize two major phenotypic differences, analyse gene expression and study the regulatory basis of the variation. Methodology. Phenotypic expression was characterized by DNA and RNA sequencing, microscopy, and differential bacteriology. Regulatory genes were identified by cloning and bioinformatics. Results/Key findings. Whereas S produced larger quantities of extracellular DNA, R was upregulated in the production of a unique chromosome 1-encoded Siphoviridae-like bacteriophage, φMSHR5848. Exploratory transcriptional analyses revealed significant differences in variant expression of genes encoding siderophores, pili assembly, type VI secretion system cluster 4 (T6SS-4) proteins, several exopolysaccharides and secondary metabolites. A single 3 base duplication in S was the only difference that separated the variants genetically. It occurred upstream of a cluster of bacteriophage-associated genes on chromosome 2 that were upregulated in S. The first two genes were involved in regulating expression of the multiple phenotypes distinguishing S and R. Conclusion. Bacteriophage-associated proteins have a major role in the phenotypic expression of MSHR5848. The goals are to determine the regulatory basis of this phenotypic variation and its role in pathogenesis and environmental persistence of B. pseudomallei .

Summary The microbiota plays a fundamental role in regulating host immunity. However, the processes involved in the initiation and regulation of immunity to the microbiota remain largely unknown. Here, we show that the skin microbiota promotes the discrete expression of defined endogenous retroviruses (ERVs). Keratinocyte-intrinsic responses to ERVs depended on cyclic GMP-AMP synthase (cGAS)/stimulator of interferon genes protein (STING) signaling and promoted the induction of commensal-specific T cells. Inhibition of ERV reverse transcription significantly impacted these responses, resulting in impaired immunity to the microbiota and its associated tissue repair function. Conversely, a lipid-enriched diet primed the skin for heightened ERV- expression in response to commensal colonization, leading to increased immune responses and tissue inflammation. Together, our results support the idea that the host may have co-opted its endogenous virome as a means to communicate with the exogenous microbiota, resulting in a multi-kingdom dialog that controls both tissue homeostasis and inflammation., Graphical abstract, Highlights • Endogenous retrovirus sensing is required for commensal-specific immunity • Reverse transcription inhibition impairs commensal-induced immunity in the skin • cGAS/STING signaling in keratinocytes is required for skin immunity to the microbiota • Enhanced endogenous retrovirus expression promotes microbiota-induced inflammation, The host immune system uses the endogenous virome to communicate with the exogenous microbiota in a multi-kingdom interaction that modulates tissue repair or inflammation.

In 2011, the Association of Analytical Communities (AOAC) International released a list of Bacillus strains relevant to biothreat molecular detection assays. We present the complete and annotated genome assemblies for the 15 strains listed on the inclusivity panel, as well as the 20 strains listed on the exclusivity panel.

Bats harbor many viruses asymptomatically, including several notorious for causing extreme virulence in humans. To identify differences between antiviral mechanisms in humans and bats, we sequenced, assembled, and analyzed the genome of Rousettus aegyptiacus, a natural reservoir of Marburg virus and the only known reservoir for any filovirus. We found an expanded and diversified KLRC/KLRD family of natural killer cell receptors, MHC class I genes, and type I interferons, which dramatically differ from their functional counterparts in other mammals. Such concerted evolution of key components of bat immunity is strongly suggestive of novel modes of antiviral defense. An evaluation of the theoretical function of these genes suggests that an inhibitory immune state may exist in bats. Based on our findings, we hypothesize that tolerance of viral infection, rather than enhanced potency of antiviral defenses, may be a key mechanism by which bats asymptomatically host viruses that are pathogenic in humans.

During routine screening for Burkholderia pseudomallei from water wells in northern Australia in areas where it is endemic, Gram-negative bacteria (strains MSMB43 T , MSMB121, and MSMB122) with a similar morphology and biochemical pattern to B. pseudomallei and B. thailandensis were coisolated with B. pseudomallei on Ashdown's selective agar. To determine the exact taxonomic position of these strains and to distinguish them from B. pseudomallei and B. thailandensis , they were subjected to a series of phenotypic and molecular analyses. Biochemical and fatty acid methyl ester analysis was unable to distinguish B. humptydooensis sp. nov. from closely related species. With matrix-assisted laser desorption ionization–time of flight analysis, all isolates grouped together in a cluster separate from other Burkholderia spp. 16S rRNA and recA sequence analyses demonstrated phylogenetic placement for B. humptydooensis sp. nov. in a novel clade within the B. pseudomallei group. Multilocus sequence typing (MLST) analysis of the three isolates in comparison with MLST data from 3,340 B. pseudomallei strains and related taxa revealed a new sequence type (ST318). Genome-to-genome distance calculations and the average nucleotide identity of all isolates to both B. thailandensis and B. pseudomallei , based on whole-genome sequences, also confirmed B. humptydooensis sp. nov. as a novel Burkholderia species within the B. pseudomallei complex. Molecular analyses clearly demonstrated that strains MSMB43 T , MSMB121, and MSMB122 belong to a novel Burkholderia species for which the name Burkholderia humptydooensis sp. nov. is proposed, with the type strain MSMB43 T (American Type Culture Collection BAA-2767; Belgian Co-ordinated Collections of Microorganisms LMG 29471; DDBJ accession numbers CP013380 to CP013382 ). IMPORTANCE Burkholderia pseudomallei is a soil-dwelling bacterium and the causative agent of melioidosis. The genus Burkholderia consists of a diverse group of species, with the closest relatives of B. pseudomallei referred to as the B. pseudomallei complex. A proposed novel species, B. humptydooensis sp. nov., was isolated from a bore water sample from the Northern Territory in Australia. B. humptydooensis sp. nov. is phylogenetically distinct from B. pseudomallei and other members of the B. pseudomallei complex, making it the fifth member of this important group of bacteria.

Here, we report the genome sequence of Yersinia pestis strain Cadman, an attenuated strain lacking the pgm locus. Y. pestis is the causative agent of plague and generally must be worked with under biosafety level 3 (BSL-3) conditions. However, strains lacking the pgm locus are considered safe to work with under BSL-2 conditions.

Whole-genome sequence (WGS) data are commonly used to design diagnostic targets for the identification of bacterial pathogens. To do this effectively, genomics databases must be comprehensive to identify the strict core genome that is specific to the target pathogen. As additional genomes are analyzed, the core genome size is reduced and there is erosion of the target-specific regions due to commonality with related species, potentially resulting in the identification of false positives and/or false negatives., IMPORTANCE A comparative analysis of 1,130 Burkholderia genomes identified unique markers for many named species, including the human pathogens B. pseudomallei and B. mallei. Due to core genome reduction and signature erosion, only 38 targets specific to B. pseudomallei/mallei were identified. By using only public genomes, a larger number of markers were identified, due to undersampling, and this larger number represents the potential for false positives. This analysis has implications for the design of diagnostics for other species where the genomic space of the target and/or closely related species is not well defined.

The genus Burkholderia encompasses both pathogenic (including Burkholderia mallei and Burkholderia pseudomallei, U.S. Centers for Disease Control and Prevention Category B listed), and nonpathogenic Gram-negative bacilli. Here we present full genome sequences for a panel of 59 Burkholderia strains, selected to aid in detection assay development.

Burkholderia mallei , the etiologic agent of glanders, is a Gram-negative, nonmotile, facultative intracellular pathogen. Although glanders has been eradicated from many parts of the world, the threat of B. mallei being used as a weapon is very real. Here we present draft genome assemblies of 8 Burkholderia mallei strains that were isolated in Turkey.

In 2011, the Association of Analytical Communities (AOAC) International released a list of Bacillus strains relevant to biothreat molecular detection assays. We present the complete and annotated genome assemblies for the 15 strains listed on the inclusivity panel, as well as the 20 strains listed on the exclusivity panel.

Francisella tularensis is a highly infectious bacterium with the potential to cause high fatality rates if infections are untreated. To aid in the development of rapid and accurate detection assays, we have sequenced and annotated the genomes of 18 F. tularensis and Francisella philomiragia strains.

The genus Burkholderia encompasses both pathogenic (including Burkholderia mallei and Burkholderia pseudomallei , U.S. Centers for Disease Control and Prevention Category B listed), and nonpathogenic Gram-negative bacilli. Here we present full genome sequences for a panel of 59 Burkholderia strains, selected to aid in detection assay development.

The genus Yersinia includes three human pathogens, of which Yersinia pestis is responsible for >2,000 illnesses each year. To aid in the development of detection assays and aid further phylogenetic elucidation, we sequenced and assembled the complete genomes of 32 strains (across 9 Yersinia species).

Single-molecule real-time (SMRT) sequencing technology with the Pacific Biosciences (PacBio) RS II platform offers the potential to obtain full-length coding regions (∼1100-bp) from MHC class I cDNAs. Despite the relatively high error rate associated with SMRT technology, high quality sequences can be obtained by circular consensus sequencing (CCS) due to the random nature of the error profile. In the present study we first validated the ability of SMRT-CCS to accurately identify class I transcripts in Mauritian-origin cynomolgus macaques (Macaca fascicularis) that have been characterized previously by cloning and Sanger-based sequencing as well as pyrosequencing approaches. We then applied this SMRT-CCS method to characterize 60 novel full-length class I transcript sequences expressed by a cohort of cynomolgus macaques from China. The SMRT-CCS method described here provides a straightforward protocol for characterization of unfragmented single-molecule cDNA transcripts that will potentially revolutionize MHC class I allele discovery in nonhuman primates and other species.

Burkholderia is a genus of betaproteobacteria that includes three notable human pathogens: B. cepacia , B. pseudomallei , and B. mallei . While B. pseudomallei and B. mallei are considered potential biowarfare agents, B. cepacia infections are largely limited to cystic fibrosis patients. Here, we present 56 Burkholderia genomes from 8 distinct species.

The Delftia acidovorans 2167 (ATCC 15668, Delftia type strain) genome was sequenced into a 6-contig scaffolded assembly of 6.78-Mb. This environmental microbe, previously named to both the Comamonas and Pseudomonas genera, is an opportunistic pathogen and often the subject of phylogenetic placement debates.

Primarily a zoonotic disease, Francisella tularensis is a fastidious intracellular pathogen and is listed as a CDC category A pathogen with notably high pathogenicity. Here we present the scaffolded genome assemblies of nine Francisella strains: eight F. tularensis and one F. philomiragia .

Generally an opportunistic pathogen in the United States, Moraxella catarrhalis has acquired resistance to multiple antibacterial/antimicrobial agents. Here, we present the complete 1.9-Mb genome of M. catarrhalis strain ATCC 25240, as deposited in NCBI under the accession number CP008804.

Bacilli are genetically and physiologically diverse, ranging from innocuous to highly pathogenic. Here, we present annotated genome assemblies for 20 strains belonging to Bacillus anthracis , B. atrophaeus , B. cereus , B. licheniformis , B. macerans , B. megaterium , B. mycoides , and B. subtilis .

Klebsiella pneumoniae is a common cause of antibiotic-resistant bacterial infections in immunocompromised individuals. Here, we present the 5.54-Mb scaffolded assembly of the type strain K. pneumoniae type strain ATCC 13883, as deposited in GenBank under accession no. JOOW00000000.

Ochrobactrum anthropi is an occasional cause of nosocomial infections; however, interest in the organism lies in its phylogenetic proximity to the genus Brucella . Here, we present the 4.9-Mb finished genome of Ochrobactrum anthropi ATCC 49687, most commonly used as an exclusionary reference organism.

The pleomorphic swarming bacilli of the genus Proteus are common human gut commensal organisms but also the causative agents of recurrent urinary tract infections and bacteremia. We sequenced and assembled the 3.99-Mbp genome of Proteus mirabilis ATCC 7002 (accession no. JOVJ00000000) and the 3.97-Mbp genome of Proteus vulgaris ATCC 49132 (accession no. JPIX00000000), both of which are commonly used reference strains.

The genus Corynebacterium is best known for the pathogen C. diphtheriae ; however, it contains mostly commensal and nonpathogenic, as well as several opportunistic, pathogens. Here, we present the 2.47-Mb scaffolded assembly of the type strain, Corynebacterium sp . ATCC 6931 (NCTC 1914), as deposited into GenBank under accession number CP008913.

A member of the normal human gut microflora, Providencia stuartii is of clinical interest due to its role in nosocomial infections of the urinary tract and because it readily acquires antibiotic resistance. Here, we present the complete genome of P. stuartii strain ATCC 33672, consisting of a 4.28-Mbp chromosome and a 48.9-kbp plasmid.

Soft-tissue infection by Pasteurella multocida in humans is usually associated with a dog- or cat-related injury, and these infections can become aggressive. We sequenced the type strain P. multocida subsp. multocida ATCC 43137 into a single closed chromosome consisting of 2,271,840 bp (40.4% G+C content), which is currently available in the NCBI GenBank under the accession number CP008918.

Yersinia spp. are animal pathogens, some of which cause human disease. We sequenced 10 Yersinia isolates (from six species: Yersinia enterocolitica , Y. fredericksenii , Y. kristensenii , Y. pestis , Y. pseudotuberculosis , and Y. ruckeri ) to high-quality draft or complete status. The genomes range in size from 3.77 to 4.94 Mbp.

Salmonella enterica constitutes a group of enteric pathogens with a broad host range, including humans, reptiles, and birds. S. enterica subsp. enterica is a common cause of inflammatory diarrhea in humans. We present the draft genome of S. enterica subsp. enterica serovar Enteritidis strain SEJ, including a 59-kbp plasmid.

Enterococcus faecalis is a nonmotile Gram-positive coccus, found both as a commensal organism in healthy humans and animals and as a causative agent of multiple diseases, in particular endocarditis. We sequenced the genome of E. faecalis ATCC 29212, a commonly used reference strain in laboratory studies, to complete “finished” annotated assembly (3 Mb).

We present the scaffolded genome assembly of Neisseria lactamica type strain A7515 (ATCC 23970) as submitted to NCBI under accession no. JOVI00000000. This type strain of the lactose-fermenting Neisseria species is often used in quality control testing and intra-genus phylogenetic analyses. The assembly includes four contigs placed into a single scaffold.

Brucella species are intracellular zoonotic pathogens which cause, among other pathologies, increased rates of abortion in ruminants. Human infections are generally associated with exposure to contaminated and unpasteurized dairy products; however Brucellae have been developed as bioweapons. Here we present 17 complete and 7 scaffolded genome assemblies of Brucella strains.

Two sibling species of tephritid fruit fly, Bactrocera tryoni and Bactrocera neohumeralis, are differentiated by their time of mating, which is genetically determined and requires interactions between the endogenous circadian clock and light intensity. The cryptochrome (cry) gene, a light-sensitive component of the circadian clock, was isolated in the two Bactrocera species. The putative amino acid sequence is identical in the two species. In the brain, in situ hybridization showed that cry is expressed in the lateral and dorsal regions of the central brain where PER immunostaining was also observed and in a peripheral cell cluster of the antennal lobes. Levels of cry mRNA were analyzed in whole head, brain, and antennae. In whole head, cry is abundantly and constantly expressed. However, in brain and antennae the transcript cycles in abundance, with higher levels during the day than at night, and cry transcripts are more abundant in the brain and antennae of B. neohumeralis than in that of B. tryoni. Strikingly, these results are duplicated in hybrid lines, generated by rare mating between B. tryoni and B. neohumeralis and then selected on the basis of mating time, suggesting a role for the cry gene in the mating isolation mechanism that differentiates the species.

Moraxella macacae is a recently described bacterial species that has been associated with at least two outbreaks of epistaxis in macaques. Here we present the first genome sequence of this novel species, isolated from a symptomatic cynomolgus macaque at the U.S. Army Medical Research Institute of Infectious Diseases.