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July 7, 2019

Chromosome and linear plasmid sequences of a 2015 human isolate of the tick-borne relapsing fever spirochete, Borrelia turicatae.

The sequences of the complete linear chromosome and 7 linear plasmids of the relapsing fever spirochete Borrelia turicatae are presented in this report. The 925,547 bp of chromosome and 380,211 bp of plasmid sequence were predicted to contain a total of 1,131 open reading frames, with an average G+C content of 29.7%. Copyright © 2016 Kingry et al.


July 7, 2019

Complete genome sequences of three outbreak-associated Legionella pneumophila isolates.

We report here the complete genome sequences of three Legionella pneumophila isolates that are associated with a Legionnaires’ disease outbreak in New York in 2012. Two clinical isolates (D7630 and D7632) and one environmental isolate (D7631) were recovered from this outbreak. A single isolate-specific virulence gene was found in D7632. These isolates were included in a large study evaluating the genomic resolution of various bioinformatics approaches for L. pneumophila serogroup 1 isolates. Copyright © 2016 Morrison et al.


July 7, 2019

E. coli O157:H7 strain EDL933 harbors multiple functional prophage-associated genes necessary for the utilization of 5-N-acetyl-9-O-acetyl neuraminic acid as a growth substrate.

Enterohemorrhagic E. coli (EHEC) O157:H7 strain EDL933 harbors multiple prophage-associated open reading frames (orfs) in its genome, which are highly homologous to the chromosomal nanS gene. The latter is part of the nanCMS-operon, which is present in most E. coli strains and encodes an esterase, which is responsible for the mono-deacetylation of 5-N-acetyl-9-O-acetyl neuraminic acid (Neu5,9Ac2). Whereas one prophage-borne orf (z1466) has been characterized in previous studies, the functions of the other nanS-homologous orfs are unknown.In the current study, the nanS-homologous orfs of EDL933 were initially studied in silico Due to their homology to the chromosomal nanS gene and their location in prophage genomes, we designated them nanS-p, and numbered the different nanS-p alleles consecutively from 1-10. The two alleles nanS-p2 and nanS-p4 were selected for production of recombinant proteins, their enzymatic activities were investigated and differences in their temperature optima were found. Furthermore, a function of these enzymes in substrate utilization could be demonstrated using an E. coli C600?nanS mutant in a growth medium with Neu5,9Ac2 as carbon source and supplementation with the different recombinant NanS-p proteins. Moreover, generation of sequential deletion of all nanS-p alleles in strain EDL933, and subsequent growth experiments demonstrated a gene-dose-effect on the utilization of Neu5,9Ac2Since Neu5,9Ac2 is an important component of human and animal gut mucus, and the nutrient availability in the large intestine is limited, we hypothesize that the presence of multiple Neu5,9Ac2-esterases provides them a nutrient supply under certain conditions in the large intestine, even if particular prophages get lost.In this study, a group of homologous prophage-borne nanS-p alleles and two of the corresponding enzymes of enterohemorrhagic E. coli (EHEC) O157:H7 strain EDL933 are characterized that may be important to provide alternative genes for substrate utilization. Copyright © 2016, American Society for Microbiology. All Rights Reserved.


July 7, 2019

Comparative genomic analysis of Klebsiella pneumoniae subsp. pneumoniae KP617 and PittNDM01, NUHL24835, and ATCC BAA-2146 reveals unique evolutionary history of this strain.

Klebsiella pneumoniae subsp. pneumoniae KP617 is a pathogenic strain that coproduces OXA-232 and NDM-1 carbapenemases. We sequenced the genome of KP617, which was isolated from the wound of a Korean burn patient, and performed a comparative genomic analysis with three additional strains: PittNDM01, NUHL24835 and ATCC BAA-2146.The complete genome of KP617 was obtained via multi-platform whole-genome sequencing. Phylogenetic analysis along with whole genome and multi-locus sequence typing of genes of the Klebsiella pneumoniae species showed that KP617 belongs to the WGLW2 group, which includes PittNDM01 and NUHL24835. Comparison of annotated genes showed that KP617 shares 98.3 % of its genes with PittNDM01. Nineteen antibiotic resistance genes were identified in the KP617 genome: bla OXA-1 and bla SHV-28 in the chromosome, bla NDM-1 in plasmid 1, and bla OXA-232 in plasmid 2 conferred resistance to beta-lactams; however, colistin- and tetracycline-resistance genes were not found. We identified 117 virulence factors in the KP617 genome, and discovered that the genes encoding these factors were also harbored by the reference strains; eight genes were lipopolysaccharide-related and four were capsular polysaccharide-related. A comparative analysis of phage-associated regions indicated that two phage regions are specific to the KP617 genome and that prophages did not act as a vehicle for transfer of antimicrobial resistance genes in this strain.Whole-genome sequencing and bioinformatics analysis revealed similarity in the genome sequences and content, and differences in phage-related genes, plasmids and antimicrobial resistance genes between KP617 and the references. In order to elucidate the precise role of these factors in the pathogenicity of KP617, further studies are required.


July 7, 2019

The novel 2016 WHO Neisseria gonorrhoeae reference strains for global quality assurance of laboratory investigations: phenotypic, genetic and reference genome characterization.

Gonorrhoea and MDR Neisseria gonorrhoeae remain public health concerns globally. Enhanced, quality-assured, gonococcal antimicrobial resistance (AMR) surveillance is essential worldwide. The WHO global Gonococcal Antimicrobial Surveillance Programme (GASP) was relaunched in 2009. We describe the phenotypic, genetic and reference genome characteristics of the 2016 WHO gonococcal reference strains intended for quality assurance in the WHO global GASP, other GASPs, diagnostics and research worldwide.The 2016 WHO reference strains (n?=?14) constitute the eight 2008 WHO reference strains and six novel strains. The novel strains represent low-level to high-level cephalosporin resistance, high-level azithromycin resistance and a porA mutant. All strains were comprehensively characterized for antibiogram (n?=?23), serovar, prolyliminopeptidase, plasmid types, molecular AMR determinants, N. gonorrhoeae multiantigen sequence typing STs and MLST STs. Complete reference genomes were produced using single-molecule PacBio sequencing.The reference strains represented all available phenotypes, susceptible and resistant, to antimicrobials previously and currently used or considered for future use in gonorrhoea treatment. All corresponding resistance genotypes and molecular epidemiological types were described. Fully characterized, annotated and finished references genomes (n?=?14) were presented.The 2016 WHO gonococcal reference strains are intended for internal and external quality assurance and quality control in laboratory investigations, particularly in the WHO global GASP and other GASPs, but also in phenotypic (e.g. culture, species determination) and molecular diagnostics, molecular AMR detection, molecular epidemiology and as fully characterized, annotated and finished reference genomes in WGS analysis, transcriptomics, proteomics and other molecular technologies and data analysis.© The Author 2016. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.


July 7, 2019

Bacterial genetics: SMRT-seq reveals an epigenetic switch.

Streptococcus pneumoniae uses genetic diversification as a strategy to achieve phenotypic plasticity. For example, DNA inversion of the hsdS genes of type I restriction-modification (R-M) systems determines whether S. pneumoniae forms opaque or transparent colonies, which have different colonization and virulence characteristics. Zhang and colleagues now use single-molecule, real-time sequencing (SMRT-seq) to show the allelic variation of hsdS that results from site-specific recombination forms part of an epigenetic switch.


July 7, 2019

Distinct Salmonella enteritidis lineages associated with enterocolitis in high-income settings and invasive disease in low-income settings.

An epidemiological paradox surrounds Salmonella enterica serovar Enteritidis. In high-income settings, it has been responsible for an epidemic of poultry-associated, self-limiting enterocolitis, whereas in sub-Saharan Africa it is a major cause of invasive nontyphoidal Salmonella disease, associated with high case fatality. By whole-genome sequence analysis of 675 isolates of S. Enteritidis from 45 countries, we show the existence of a global epidemic clade and two new clades of S. Enteritidis that are geographically restricted to distinct regions of Africa. The African isolates display genomic degradation, a novel prophage repertoire, and an expanded multidrug resistance plasmid. S. Enteritidis is a further example of a Salmonella serotype that displays niche plasticity, with distinct clades that enable it to become a prominent cause of gastroenteritis in association with the industrial production of eggs and of multidrug-resistant, bloodstream-invasive infection in Africa.


July 7, 2019

New Delhi metallo-ß-lactamase-1-producing Klebsiella pneumoniae, Florida, USA(1).

New Delhi metallo-ß-lactamase (NDM)–producing Enterobacteriaceae have swiftly spread worldwide since an initial report in 2008 from a patient who had been transferred from India back home to Sweden (1). Epidemiologically, the global diffusion of NDM-1 producers has been associated with the Indian subcontinent and the Balkan region, which are considered the primary and secondary reservoirs of these pathogens, respectively (1). However, recent reports suggest that countries in the Middle East may constitute another potential reservoir for NDM-1 producers (1). More than 100 NDM-producing isolates have been reported in the United States, most of which were associated with recent travel from the Indian subcontinent (2,3). We report an NDM-1–producing Klebsiella pneumoniae strain that was recovered from a patient who had been transferred from Iran to a hospital in Florida, United States.


July 7, 2019

Chromosomal locations of mcr-1 and bla CTX-M-15 in fluoroquinolone-resistant Escherichia coli ST410.

To the Editor: Recently, Yi-Yun Liu et al. reported on the discovery of mcr-1, a plasmidborne resistance gene mediating resistance to colistin, in isolates obtained from humans and animals (1). Since the original publication, mcr-1 with or without the insertion element ISApl1 has been detected on plasmids of different incompatibility groups, including IncI2, IncHI2, and IncX4, and in many different countries (1–3). Because colistin is a last-resort parenteral antimicrobial drug, the transfer of mcr-1 by conjugation or through mobilizable plasmids raises concern about the emergence of pan-resistant Enterobacteriaceae.


July 7, 2019

Complete Genome Sequences of Four Enterohemolysin-Positive (ehxA) Enterocyte Effacement-Negative Shiga Toxin-Producing Escherichia coli Strains

Shiga toxin-producing Escherichia coli (STEC) strains are important foodborne pathogens associated with human disease. Most disease-associated STEC strains carry the locus of enterocyte effacement (LEE); however, regularly LEE-negative STEC strains are recovered from ill patients. Few reference sequences are available for these isolate types. Here, we report here the complete genome sequences for four LEE-negative STEC strains. Copyright © 2016 Lorenz et al.


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