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Asset Tag: Pathogen

July 7, 2019

Molecular and biological characterization of a new isolate of guinea pig cytomegalovirus.

Development of a vaccine against congenital infection with human cytomegalovirus is complicated by the issue of re-infection, with subsequent vertical transmission, in women with pre-conception immunity to the virus. The study of experimental therapeutic prevention of re-infection would ideally be undertaken in a small animal model, such as the guinea pig cytomegalovirus (GPCMV) model, prior to human clinical trials. However, the ability to model re-infection in the GPCMV model has been limited by availability of only one strain of virus, the 22122 strain, isolated in 1957. In this report, we describe the isolation of a new GPCMV strain, the CIDMTR strain. This strain demonstrated morphological characteristics of a typical Herpesvirinae by electron microscopy. Illumina and PacBio sequencing demonstrated a genome of 232,778 nt. Novel open reading frames ORFs not found in reference strain 22122 included an additional MHC Class I homolog near the right genome terminus. The CIDMTR strain was capable of dissemination in immune compromised guinea pigs, and was found to be capable of congenital transmission in GPCMV-immune dams previously infected with salivary gland-adapted strain 22122 virus. The availability of a new GPCMV strain should facilitate study of re-infection in this small animal model.

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July 7, 2019

Complete closed genome sequences of three Bibersteinia trehalosi nasopharyngeal isolates from cattle with shipping fever.

Bibersteinia trehalosi is a respiratory pathogen affecting cattle and related ruminants worldwide. B. trehalosi is closely related to Mannheimia haemolytica and is often associated with bovine respiratory disease complex (BRDC), a polymicrobial multifactorial disease. We present three complete closed genome sequences of this species generated using an automated assembly pipeline.

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July 7, 2019

Genome sequences of Corynebacterium pseudotuberculosis strains 48252 (human, pneumonia), CS_10 (lab strain), Ft_2193/ 67 (goat, pus), and CCUG 27541.

Here we report the genome sequencess of four Corynebacterium pseudotuberculosis strains. These include a strain isolated from a patient with C. pseudotuberculosis pneumonia (48252), a strain isolated from pus in goat (Ft_2193/67), a laboratory strain originating from strain Ft_2193/67 (CS_10), and the draft genome of an equine reference strain, CCUG 27541. Copyright © 2014 Håvelsrud et al.

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July 7, 2019

Complete genome sequences of eight Helicobacter pylori strains with different virulence factor genotypes and methylation profiles, isolated from patients with diverse gastrointestinal diseases on Okinawa Island, Japan, determined using PacBio Single-Molecule Real-Time Technology.

We report the complete genome sequences of eight Helicobacter pylori strains isolated from patients with gastrointestinal diseases in Okinawa, Japan. Whole-genome sequencing and DNA methylation detection were performed using the PacBio platform. De novo assembly determined a single, complete contig for each strain. Furthermore, methylation analysis identified virulence factor genotype-dependent motifs.

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July 7, 2019

First genome sequences of Achromobacter phages reveal new members of the N4 family.

Multi-resistant Achromobacter xylosoxidans has been recognized as an emerging pathogen causing nosocomially acquired infections during the last years. Phages as natural opponents could be an alternative to fight such infections. Bacteriophages against this opportunistic pathogen were isolated in a recent study. This study shows a molecular analysis of two podoviruses and reveals first insights into the genomic structure of Achromobacter phages so far.Growth curve experiments and adsorption kinetics were performed for both phages. Adsorption and propagation in cells were visualized by electron microscopy. Both phage genomes were sequenced with the PacBio RS II system based on single molecule, real-time (SMRT) technology and annotated with several bioinformatic tools. To further elucidate the evolutionary relationships between the phage genomes, a phylogenomic analysis was conducted using the genome Blast Distance Phylogeny approach (GBDP).In this study, we present the first detailed analysis of genome sequences of two Achromobacter phages so far. Phages JWAlpha and JWDelta were isolated from two different waste water treatment plants in Germany. Both phages belong to the Podoviridae and contain linear, double-stranded DNA with a length of 72329 bp and 73659 bp, respectively. 92 and 89 putative open reading frames were identified for JWAlpha and JWDelta, respectively, by bioinformatic analysis with several tools. The genomes have nearly the same organization and could be divided into different clusters for transcription, replication, host interaction, head and tail structure and lysis. Detailed annotation via protein comparisons with BLASTP revealed strong similarities to N4-like phages.Analysis of the genomes of Achromobacter phages JWAlpha and JWDelta and comparisons of different gene clusters with other phages revealed that they might be strongly related to other N4-like phages, especially of the Escherichia group. Although all these phages show a highly conserved genomic structure and partially strong similarities at the amino acid level, some differences could be identified. Those differences, e.g. the existence of specific genes for replication or host interaction in some N4-like phages, seem to be interesting targets for further examination of function and specific mechanisms, which might enlighten the mechanism of phage establishment in the host cell after infection.

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July 7, 2019

The complete genome sequence of Clostridium indolis DSM 755(T.).

Clostridium indolis DSM 755(T) is a bacterium commonly found in soils and the feces of birds and mammals. Despite its prevalence, little is known about the ecology or physiology of this species. However, close relatives, C. saccharolyticum and C. hathewayi, have demonstrated interesting metabolic potentials related to plant degradation and human health. The genome of C. indolis DSM 755(T) reveals an abundance of genes in functional groups associated with the transport and utilization of carbohydrates, as well as citrate, lactate, and aromatics. Ecologically relevant gene clusters related to nitrogen fixation and a unique type of bacterial microcompartment, the CoAT BMC, are also detected. Our genome analysis suggests hypotheses to be tested in future culture based work to better understand the physiology of this poorly described species.

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July 7, 2019

Novel giant siphovirus from Bacillus anthracis features unusual genome characteristics.

Here we present vB_BanS-Tsamsa, a novel temperate phage isolated from Bacillus anthracis, the agent responsible for anthrax infections in wildlife, livestock and humans. Tsamsa phage is a giant siphovirus (order Caudovirales), featuring a long, flexible and non-contractile tail of 440 nm (not including baseplate structure) and an isometric head of 82 nm in diameter. We induced Tsamsa phage in samples from two different carcass sites in Etosha National Park, Namibia. The Tsamsa phage genome is the largest sequenced Bacillus siphovirus, containing 168,876 bp and 272 ORFs. The genome features an integrase/recombinase enzyme, indicative of a temperate lifestyle. Among bacterial strains tested, the phage infected only certain members of the Bacillus cereus sensu lato group (B. anthracis, B. cereus and B. thuringiensis) and exhibited moderate specificity for B. anthracis. Tsamsa lysed seven out of 25 B. cereus strains, two out of five B. thuringiensis strains and six out of seven B. anthracis strains tested. It did not lyse B. anthracis PAK-1, an atypical strain that is also resistant to both gamma phage and cherry phage. The Tsamsa endolysin features a broader lytic spectrum than the phage host range, indicating possible use of the enzyme in Bacillus biocontrol.

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July 7, 2019

Safety of the surrogate microorganism Enterococcus faecium NRRL B-2354 for use in thermal process validation.

Enterococcus faecium NRRL B-2354 is a surrogate microorganism used in place of pathogens for validation of thermal processing technologies and systems. We evaluated the safety of strain NRRL B-2354 based on its genomic and functional characteristics. The genome of E. faecium NRRL B-2354 was sequenced and found to comprise a 2,635,572-bp chromosome and a 214,319-bp megaplasmid. A total of 2,639 coding sequences were identified, including 45 genes unique to this strain. Hierarchical clustering of the NRRL B-2354 genome with 126 other E. faecium genomes as well as pbp5 locus comparisons and multilocus sequence typing (MLST) showed that the genotype of this strain is most similar to commensal, or community-associated, strains of this species. E. faecium NRRL B-2354 lacks antibiotic resistance genes, and both NRRL B-2354 and its clonal relative ATCC 8459 are sensitive to clinically relevant antibiotics. This organism also lacks, or contains nonfunctional copies of, enterococcal virulence genes including acm, cyl, the ebp operon, esp, gelE, hyl, IS16, and associated phenotypes. It does contain scm, sagA, efaA, and pilA, although either these genes were not expressed or their roles in enterococcal virulence are not well understood. Compared with the clinical strains TX0082 and 1,231,502, E. faecium NRRL B-2354 was more resistant to acidic conditions (pH 2.4) and high temperatures (60°C) and was able to grow in 8% ethanol. These findings support the continued use of E. faecium NRRL B-2354 in thermal process validation of food products.

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July 7, 2019

Genome Sequence of Pseudomonas brassicacearum DF41.

Pseudomonas brassicacearum DF41, a Gram-negative soil bacterium, is able to suppress the fungal pathogen Sclerotinia sclerotiorum through a process known as biological control. Here, we present a 6.8-Mb assembly of its genome, which is the second fully assembled genome of a P. brassicacearum strain.

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July 7, 2019

Genome sequences of two carbapenemase-resistant Klebsiella pneumoniae ST258 isolates.

Klebsiella pneumoniae, an ESKAPE group (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogen, has acquired multiple antibiotic resistance genes and is becoming a serious public health threat. Here, we report the genome sequences of two representative strains of K. pneumoniae from the emerging K. pneumoniae carbapenemase (KPC) outbreak in northeast Ohio belonging to sequence type 258 (ST258) (isolates Kb140 and Kb677, which were isolated from blood and urine, respectively). Both isolates harbor a blaKPC gene, and strain Kb140 carries blaKPC-2, while Kb677 carries blaKPC-3. Copyright © 2014 Ramirez et al.

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