Whole-genome sequence of Chryseobacterium oranimense, a colistin-resistant bacterium isolated from a cystic fibrosis patient in France.

For the first time, we report the whole-genome sequence analysis of Chryseobacterium oranimense G311, a multidrug-resistant bacterium, from a cystic fibrosis patient in France, including resistance to colistin. Whole-genome sequencing of C. oranimense G311 was performed using Ion Torrent PGM, and RAST, the EMBL-EBI server, and the Antibiotic Resistance Gene-ANNOTation (ARG-ANNOT) database were used for annotation of all genes, including antibiotic resistance (AR) genes. General features of the C. oranimense G311 draft genome were compared to the other available genomes of Chryseobacterium gleum and Chryseobacterium sp. strain CF314. C. oranimense G311 was found to be resistant to all ß-lactams, including imipenem, and to colistin. The genome size of C. oranimense G311 is 4,457,049 bp in length, with 37.70% GC content. We found 27 AR genes in the genome, including ß-lactamase genes which showed little similarity to the known ß-lactamase genes and could likely be novel. We found the type I polyketide synthase operon followed by a zeaxanthin glycosyltransferase gene in the genome, which could impart the yellow pigmentation of the isolate. We located the O-antigen biosynthesis cluster, and we also discovered a novel capsular polysaccharide biosynthesis cluster. We also found known mutations in the orthologs of the pmrA (E8D), pmrB (L208F and P360Q), and lpxA (G68D) genes. We speculate that the presence of the capsular cluster and mutations in these genes could explain the resistance of this bacterium to colistin. We demonstrate that whole-genome sequencing was successfully applied to decipher the resistome of a multidrug resistance bacterium associated with cystic fibrosis patients.

NDM-5 carbapenemase-encoding gene in multidrug-resistant clinical isolates of Escherichia coli from Algeria.

Here, we report the first autochthonous cases of infections caused by blaNDM-5 New Delhi metallo-ß-lactamase-producing Escherichia coli strains recovered from urine and blood specimens of three patients from Algeria between January 2012 and February 2013. The three isolates belong to sequence type 2659 and they coexpress blaCTX-M-15 with the blaTEM-1 and blaaadA2 genes.

ARG-ANNOT, a new bioinformatic tool to discover antibiotic resistance genes in bacterial genomes.

ARG-ANNOT (Antibiotic Resistance Gene-ANNOTation) is a new bioinformatic tool that was created to detect existing and putative new antibiotic resistance (AR) genes in bacterial genomes. ARG-ANNOT uses a local BLAST program in Bio-Edit software that allows the user to analyze sequences without a Web interface. All AR genetic determinants were collected from published works and online resources; nucleotide and protein sequences were retrieved from the NCBI GenBank database. After building a database that includes 1,689 antibiotic resistance genes, the software was tested in a blind manner using 100 random sequences selected from the database to verify that the sensitivity and specificity were at 100% even when partial sequences were queried. Notably, BLAST analysis results obtained using the rmtF gene sequence (a new aminoglycoside-modifying enzyme gene sequence that is not included in the database) as a query revealed that the tool was able to link this sequence to short sequences (17 to 40 bp) found in other genes of the rmt family with significant E values. Finally, the analysis of 178 Acinetobacter baumannii and 20 Staphylococcus aureus genomes allowed the detection of a significantly higher number of AR genes than the Resfinder gene analyzer and 11 point mutations in target genes known to be associated with AR. The average time for the analysis of a genome was 3.35 ± 0.13 min. We have created a concise database for BLAST using a Bio-Edit interface that can detect AR genetic determinants in bacterial genomes and can rapidly and easily discover putative new AR genetic determinants.

Emergence of VIM-2 and IMP-15 carbapenemases and inactivation of oprD gene in carbapenem-resistant Pseudomonas aeruginosa clinical isolates from Lebanon.

We report here the emergence of VIM-2 and IMP-15 carbapenemases in a series of clinical isolates of carbapenem-resistant Pseudomonas aeruginosa in Lebanon. We also describe the disruption of the oprD gene by either mutations or insertion sequence (IS) elements ISPa1328 and ISPre2 isoform. Our study reemphasizes a rapid dissemination of the VIM-2 carbapenemase-encoding gene in clinical isolates of P. aeruginosa in the Mediterranean basin.

A Genetic Locus in Elizabethkingia anophelis Associated with Elevated Vancomycin Resistance and Multiple Antibiotic Reduced Susceptibility.

The Gram-negative Elizabethkingia express multiple antibiotic resistance and cause severe opportunistic infections. Vancomycin is commonly used to treat Gram-positive infections and has also been used to treat Elizabethkingia infections, even though Gram-negative organisms possess a vancomycin permeability barrier. Elizabethkingia anophelis appeared relatively vancomycin-susceptible and challenge with this drug led to morphological changes indicating cell lysis. In stark contrast, vancomycin growth challenge revealed that E. anophelis populations refractory to vancomycin emerged. In addition, E. anophelis vancomycin-selected mutants arose at high frequencies and demonstrated elevated vancomycin resistance and reduced susceptibility to other antimicrobials. All mutants possessed a SNP in a gene (vsr1 = vancomycin-susceptibility regulator 1) encoding a PadR family transcriptional regulator located in the putative operon vsr1-ORF551, which is conserved in other Elizabethkingia spp as well. This is the first report linking a padR homologue (vsr1) to antimicrobial resistance in a Gram-negative organism. We provide evidence to support that vsr1 acts as a negative regulator of vsr1-ORF551 and that vsr1-ORF551 upregulation is observed in vancomycin-selected mutants. Vancomycin-selected mutants also demonstrated reduced cell length indicating that cell wall synthesis is affected. ORF551 is a membrane-spanning protein with a small phage shock protein conserved domain. We hypothesize that since vancomycin-resistance is a function of membrane permeability in Gram-negative organisms, it is likely that the antimicrobial resistance mechanism in the vancomycin-selected mutants involves altered drug permeability.

Characterization of three Francisella tularensis genomes from Oklahoma, USA.

Francisella tularensis , the causative agent for tularaemia, is a Tier 1 select agent, and a pan-species pathogen of global significance due to its zoonotic potential. Consistent genome characterization of the pathogen is essential to identify novel genes, virulence factors, antimicrobial resistance genes, for studying phylogenetics and other features of interest. This study was conducted to understand the genetic variations among genomes of F. tularensis isolated from two felines and one human source. Pan-genome analysis revealed that 97.7 % of genes were part of the core genome. All three F. tularensis isolates were assigned to sequence type A based on single nucleotide polymorphisms (SNPs) in sdhA. Most of the virulence genes were part of the core genome. An antibiotic resistance gene coding for class A beta-lactamase was detected in all three isolates. Phylogenetic analysis showed that these isolates clustered with other isolates reported from Central and South-Central USA. Assessment of large sets of the F. tularensis genome sequences is essential in understanding pathogen dynamics, geographical distribution and potential zoonotic implications.

Apt (Adenine Phosphoribosyltransferase) Mutation in Laboratory-Selected Vancomycin-Intermediate Staphylococcus aureus.

Comparative genomic sequencing of laboratory-derived vancomycin-intermediate Staphylococcusaureus (VISA) (MM66-3 and MM66-4) revealed unique mutations in both MM66-3 (in apt and ssaA6), and MM66-4 (in apt and walK), compared to hetero-VISA parent strain MM66. Transcriptional profiling revealed that both MM66 VISA shared 79 upregulated genes and eight downregulated genes. Of these, 30.4% of the upregulated genes were associated with the cell envelope, whereas 75% of the downregulated genes were associated with virulence. In concordance with mutations and transcriptome alterations, both VISA strains demonstrated reduced autolysis, reduced growth in the presence of salt and reduced virulence factor activity. In addition to mutations in genes linked to cell wall metabolism (ssaA6 and walK), the same mutation in apt which encodes adenine phosphoribosyltransferase, was confirmed in both MM66 VISA. Apt plays a role in both adenine metabolism and accumulation and both MM66 VISA grew better than MM66 in the presence of adenine or 2-fluoroadenine indicating a reduction in the accumulation of these growth inhibiting compounds in the VISA strains. MM66 apt mutants isolated via 2-fluoroadenine selection also demonstrated reduced susceptibility to the cell wall lytic dye Congo red and vancomycin. Finding that apt mutations contribute to reduced vancomycin susceptibility once again suggests a role for altered purine metabolism in a VISA mechanism.

In Silico Prediction of Antibiotic Resistance in Mycobacterium ulcerans Agy99 through Whole Genome Sequence Analysis.

Buruli ulcer is an emerging infectious disease caused by Mycobacterium ulcerans that has been reported from 33 countries. Antimicrobial agents either alone or in combination with surgery have been proved to be clinically relevant and therapeutic strategies have been deduced mainly from the empirical experience. The genome sequences of M. ulcerans strain AGY99, M. ulcerans ecovar liflandii, and three Mycobacterium marinum strains were analyzed to predict resistance in these bacteria. Fourteen putative antibiotic resistance genes from different antibiotics classes were predicted in M. ulcerans and mutation in katG (R431G) and pncA (T47A, V125I) genes were detected, that confer resistance to isoniazid and pyrazinamide, respectively. No mutations were detected in rpoB, gyrA, gyrB, rpsL, rrs, emb, ethA, 23S ribosomal RNA genes and promoter region of inhA and ahpC genes associated with resistance. Our results reemphasize the usefulness of in silico analysis for the prediction of antibiotic resistance in fastidious bacteria.

Draft Genome Sequences of Eight Streptogramin-Resistant Enterococcus Species Isolated from Animal and Environmental Sources in the United States.

Here, we present the draft genome sequences of eight streptogramin-resistant Enterococcus species isolated from animals and an environmental source in the United States from 2001 to 2004. Antimicrobial resistance genes were identified conferring resistance to the macrolide-lincosamide-streptogramins, aminoglycosides, tetracyclines, beta-lactams, and glycopeptides.

Whole genome sequencing of bacteria in cystic fibrosis as a model for bacterial genome adaptation and evolution.

Cystic fibrosis (CF) airways harbor a wide variety of new and/or emerging multidrug resistant bacteria which impose a heavy burden on patients. These bacteria live in close proximity with one another, which increases the frequency of lateral gene transfer. The exchange and movement of mobile genetic elements and genomic islands facilitate the spread of genes between genetically diverse bacteria, which seem to be advantageous to the bacterium as it allows adaptation to the new niches of the CF lungs. Niche adaptation is one of the major evolutionary forces shaping bacterial genome composition and in CF the chronic strains adapt and become less virulent. The purpose of this review is to shed light on CF bacterial genome alterations. Next-generation sequencing technology is an exciting tool that may help us to decipher the genome architecture and the evolution of bacteria colonizing CF lungs.

Genome analysis of NDM-1 producing Morganella morganii clinical isolate.

OBJECTIVE: To analyze the resistome and virulence genes of Morganella morganii F675, a multidrug-resistant clinical isolate using whole genome sequencing (WGS). METHODS: M. morganii F675 was isolated from a patient from Jerusalem, Israel. WGS was performed using both 454 and SOLiD sequencing technologies. Analyses of the bacterial resistome and other virulence genes were performed in addition to comparison with other available M. morganii genomes. RESULTS: The assembled sequence had a genome size of 4,127,528 bp with G+C content of 51%. The resistome consisted of 13 antibiotic resistance genes including blaNDM-1 located in a plasmid likely acquired from Acinetobacter spp. Moreover, we characterized for the first time the whole lipid A biosynthesis pathway in this species along with the O-antigen gene cluster, the urease gene cluster and several other virulence genes. CONCLUSION: The WGS analysis of this pathogen further provides insight into its pathogenicity and resistance to antibiotics.

Worldwide emergence of colistin resistance in Klebsiella pneumoniae from healthy humans and patients in Lao PDR, Thailand, Israel, Nigeria and France owing to inactivation of the PhoP/PhoQ regulator mgrB: an epidemiological and molecular study.

The emergence of colistin-resistant Klebsiella pneumoniae (CRKP) is a major public health concern worldwide. In this study, the prevalence and molecular basis of colistin resistance in CRKP isolated from healthy individuals and patients in Lao PDR, Thailand, Nigeria and France were investigated. Stool samples were screened by culture for the presence of colistin-resistant Klebsiella spp. Whole-genome sequence analysis was used to decipher the molecular mechanism of colistin resistance in a blaNDM-1-positive in vitro-selected CRKP mutant. PCR amplification and sequencing of the mgrB genetic environment was performed for all CRKP isolates as well as control colistin-susceptible K. pneumoniae (CSKP) isolates recovered from the same stools. A total of 869 stool samples were screened for colistin-resistant Klebsiella spp., yielding 32 CRKP and 2 colistin-resistant Klebsiella oxytoca. Comparative whole-genome sequence analysis revealed that an in vitro-selected CRKP mutant had an insertion sequence in its mgrB gene, as well as missense mutations in other selected clones. Of the 34 colistin-resistant Klebsiella spp. isolates, 14 (41.2%; 13 CRKP and 1 K. oxytoca) from the four countries also had various defects in their mgrB genes, but no such defects were found in the CSKP controls (P<10(-4)). Few mutations were observed in pmrAB compared with mgrB among the CRKP isolates. The worldwide emergence of CRKP is a major public health concern. Detection and surveillance of such strains are warranted to prevent an uncontrollable pandemic. Inactivation of the PhoP/PhoQ regulator gene mgrB is associated with ≥40% of colistin resistance among the CRKP isolates observed in this study.