Paracoccus denitrificans is a heterotrophic organism capable of oxidizing ammonia to nitrite during growth on an organic carbon and energy source. This pathway, termed heterotrophic nitrification, ...requires the concerted action of an ammonia monooxygenase (AMO) and hydroxylamine oxidase (HAO). The genes required for heterotrophic nitrification have been isolated by introducing a Pa. denitrificans genomic library into Pseudomonas putida and screening for the accumulation of nitrite. In contrast to the situation in chemolithoautotrophic ammonia oxidizers, the genes encoding AMO and HAO are present in single linked copies in the genome of Pa. denitrificans. AMO from Pa. denitrificans expressed in Ps. putida is capable of oxidizing ethene (ethylene) to epoxyethane (ethylene oxide), which is indicative of a relaxed substrate specificity. Further, when expressed in the methylotroph Methylobacterium extorquens AM1, the AMO endows on this organism the ability to grow on ethene and methane. Thus, the Pa. denitrificans AMO is capable of oxidizing methane to methanol, as is the case for the AMO from Nitrosomonas europaea. The heterotrophic nitrification genes are moderately toxic in M. extorquens, more toxic in Ps. putida, and non-toxic in Escherichia coli. Toxicity is due to the activity of the gene products in M. extorquens, and both expression and activity in Ps. putida. This is the first time that the genes encoding an active AMO have been expressed in a heterologous host.
Abstract
The outbreak strain of _E. coli_ O104:H4 has been sequenced by several groups and made available publicly for CrowdSourcing purposes. Genome comparisons of the complete finished sequence of ...TY2482 (BGI), have been made with the draft assemblies of c22711 (PacBio) and an historical outbreak strain from 2001 (U. Münster & Life Technologies). A plasmid, pTY2, carrying the _agg_ operon specifying the genes for aggregative adherence fimbriae reveals a frameshift in a gene, _aggB_, that may result in altered binding _in vivo_ compared to the unframeshifted state. Comparisons additionally reveal the presence of genomic islands specific to the outbreak strain relative to other sequenced _E. coli_ strains. These regions, and islands shared with the closest previously sequenced relative _E. coli_ 55989 have been analyzed for insertion sequences and transposable elements. Several islands found in the above strains that are not present in other sequenced _E. coli_ are found to harbor a large-scale expansion of mobile elements that are by and large confined to these hotspot or permissive areas of the chromosome. The implication is that these regions are in genomic flux and may represent specific areas of future concern due to the possibility of mobilisation of the associated genomic features likely responsible for the pathogenic features and antibiotic resistance seen in these strains.
Abstract
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen particularly associated with the inherited disease cystic fibrosis (CF). Pseudomonas aeruginosa is well known to have a large ...and adaptable genome that enables it to colonise a wide range of ecological niches. Here, we have used a comparative genomics approach to identify changes that occur during infection of the CF lung. We used the mucoid phenotype as an obvious marker of host adaptation and compared these genomes to analyse SNPs, indels and islands within near-isogenic pairs. To commence the correction of the natural bias towards clinical isolates in genomics studies and to widen our understanding of the genomic diversity of P. aeruginosa, we included four environmental isolates in our analysis. Our data suggest that genome plasticity plays an important role in chronic infection and that the strains sequenced in this study are representative of the two major phylogenetic groups as determined by core genome SNP analysis.
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BFBNIB, FZAB, GIS, IJS, KILJ, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Coagulase Negative Staphylococci (CoNS) are common commensals of human skin, account for nearly 20% of the microbiota in infants and are thought to promote early immune responses in healthy babies. ...However, CoNS are opportunistic pathogens and in the UK between 2005 and 2014 were responsible for 57% of episodes of Late Onset Sepsis (LOS). In neonatal intensive care units (NICUs) this is a major concern and antiseptics are used to prevent vascular catheter infections. Chlorhexidine (CHX) and Octenidine (OCT) are the most common agents used for skin antisepsis, but evidence is emerging of antiseptic tolerance amongst CoNS.
We undertook a longitudinal survey of CoNS from skin and rectal swabs isolated from babies in two NICUs from countries with different antiseptic regimens (UK and Germany). Over 1000 isolates were characterised for antimicrobial susceptibility and sequenced. The most frequent species isolated were S. epidermidis and S. haemolyticus with similar strain types present in both units. Reduced susceptibility to CHX and OCT was observed in UK isolates (where CHX is used), compared to German isolates (where OCT is used).
Analysis of genome data using GWAS and clustering techniques has identified loci associated with antimicrobial susceptibility. Comparison of isolates taken on admission and thereafter, demonstrated that babies acquired isolates with decreased antiseptic tolerance after admission. This data provides new information about the phylogeny of CoNS in NICUs and suggest different potentials for selection of resistance between antiseptics commonly used in neonatal care.
Burkholderia pseudomallei is a recognized biothreat agent and the causative agent of melioidosis. This Gram-negative bacterium exists as a soil saprophyte in melioidosis-endemic areas of the world ...and accounts for 20% of community-acquired septicaemias in northeastern Thailand where half of those affected die. Here we report the complete genome of B. pseudomallei, which is composed of two chromosomes of 4.07 megabase pairs and 3.17 megabase pairs, showing significant functional partitioning of genes between them. The large chromosome encodes many of the core functions associated with central metabolism and cell growth, whereas the small chromosome carries more accessory functions associated with adaptation and survival in different niches. Genomic comparisons with closely and more distantly related bacteria revealed a greater level of gene order conservation and a greater number of orthologous genes on the large chromosome, suggesting that the two replicons have distinct evolutionary origins. A striking feature of the genome was the presence of 16 genomic islands (GIs) that together made up 6.1% of the genome. Further analysis revealed these islands to be variably present in a collection of invasive and soil isolates but entirely absent from the clonally related organism B. mallei. We propose that variable horizontal gene acquisition by B. pseudomallei is an important feature of recent genetic evolution and that this has resulted in a genetically diverse pathogenic species.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Considerably improved characterisation of the urine and prostate microbiomes are provided, including the identification of four novel bacteria. These discoveries provided a platform for the ...identified group of five anaerobic bacterial genera, called the anaerobic bacteria biomarker set, associated with aggressive prostate cancer.
Bacteria play a suspected role in the development of several cancer types, and associations between the presence of particular bacteria and prostate cancer have been reported.
To provide improved characterisation of the prostate and urine microbiome and to investigate the prognostic potential of the bacteria present.
Microbiome profiles were interrogated in sample collections of patient urine (sediment microscopy: n = 318, 16S ribosomal amplicon sequencing: n = 46; and extracellular vesicle RNA-seq: n = 40) and cancer tissue (n = 204).
Microbiomes were assessed using anaerobic culture, population-level 16S analysis, RNA-seq, and whole genome DNA sequencing.
We demonstrate an association between the presence of bacteria in urine sediments and higher D’Amico risk prostate cancer (discovery, n = 215 patients, p < 0.001; validation, n = 103, p < 0.001, χ2 test for trend). Characterisation of the bacterial community led to the (1) identification of four novel bacteria (Porphyromonas sp. nov., Varibaculum sp. nov., Peptoniphilus sp. nov., and Fenollaria sp. nov.) that were frequently found in patient urine, and (2) definition of a patient subgroup associated with metastasis development (p = 0.015, log-rank test). The presence of five specific anaerobic genera, which includes three of the novel isolates, was associated with cancer risk group, in urine sediment (p = 0.045, log-rank test), urine extracellular vesicles (p = 0.039), and cancer tissue (p = 0.035), with a meta-analysis hazard ratio for disease progression of 2.60 (95% confidence interval: 1.39–4.85; p = 0.003; Cox regression). A limitation is that functional links to cancer development are not yet established.
This study characterises prostate and urine microbiomes, and indicates that specific anaerobic bacteria genera have prognostic potential.
In this study, we investigated the presence of bacteria in patient urine and the prostate. We identified four novel bacteria and suggest a potential prognostic utility for the microbiome in prostate cancer.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
49.
The devil is in the detail Bentley, Stephen D.; Thomson, Nicholas R.; Sebaihia, Mohammed ...
Trends in microbiology (Regular ed.),
06/2003, Volume:
11, Issue:
6
Journal Article
Peer reviewed
Microbial genomics continues to expand in all directions. Here we report on new additions to the complete genome portfolio from a diverse set of bacteria comprising two enterics, an obligate ...intracellular pathogen, an obligate chemolithotroph and a soil-dwelling antibiotic producer. This set also adds to the depth of genome data. One of the genomes is the second of its genus to be completed and two are actually the same serological group as previously sequenced strains.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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