Project description:BACKGROUND:Classification of pathogenic Escherichia coli (E. coli) has traditionally relied on detecting specific virulence associated genes (VAGs) or combinations thereof. For E. coli isolated from faecal samples, the presence of specific genes associated with different intestinal pathogenic pathovars will determine their classification and further course of action. However, the E. coli genome is not a static entity, and hybrid strains are emerging that cross the pathovar definitions. Hybrid strains may show gene contents previously associated with several distinct pathovars making the correct diagnostic classification difficult. We extended the analysis of routinely submitted faecal isolates to include known virulence associated genes that are usually not examined in faecal isolates to detect the frequency of possible hybrid strains. METHODS:From September 2012 to February 2013, 168 faecal isolates of E. coli routinely submitted to the Norwegian Institute of Public Health (NIPH) from clinical microbiological laboratories throughout Norway were analysed for 33 VAGs using multiplex-PCR, including factors associated with extraintestinal pathogenic E. coli (ExPEC) strains. The strains were further typed by Multiple Locus Variable-Number Tandem-Repeat Analysis (MLVA), and the phylogenetic grouping was determined. One isolate from the study was selected for whole genome sequencing (WGS) with a combination of Oxford Nanopore's MinION and Illumina's MiSeq. RESULTS:The analysis showed a surprisingly high number of strains carrying ExPEC associated VAGs and strains carrying a combination of both intestinal pathogenic E. coli (IPEC) and ExPEC VAGs. In particular, 93.5% (101/108) of isolates classified as belonging to an IPEC pathovar additionally carried ExPEC VAGs. WGS analysis of a selected hybrid strain revealed that it could, with present classification criteria, be classified as belonging to all of the Enteropathogenic Escherichia coli (EPEC), Uropathogenic Escherichia coli (UPEC), Neonatal meningitis Escherichia coli (NMEC) and Avian pathogenic Escherichia coli (APEC) pathovars. CONCLUSION:Hybrid ExPEC/IPEC E. coli strains were found at a very high frequency in faecal samples and were in fact the predominant species present. A sequenced hybrid isolate was confirmed to be a cross-pathovar strain possessing recognised hallmarks of several pathovars, and a genome heavily influenced by horizontal gene transfer.
Project description:We identified the mucus-activatable Shiga toxin genotype stx2d in the most common hemolytic uremic syndrome-associated Escherichia coli serotype, O157:H7. stx2d was detected in a strain isolated from a 2-year-old boy with bloody diarrhea in Spain, and whole-genome sequencing was used to confirm and fully characterize the strain.
Project description:Escherichia coli strain BL21 is one of the widely used bacterial hosts for high-level recombinant protein production and for other applications. Here, we present the complete genome sequence of a commercial version of the Escherichia coli BL21 strain.
Project description:BACKGROUND:Disease prevention and control is a significant part in the ex-situ conservation of the endangered red panda (Ailurus fulgens), being bacterial infection is one of the most important health threats to the captive population. To date, studies about the infection caused by Escherichia coli in the red panda are scarce. This study was conducted to determine the cause of death of a captive red panda through clinical symptoms, complete blood count, biochemical analysis, pathological diagnosis and bacterial whole genome sequencing. CASE PRESENTATION:The following report describes a case of a 1.5?year old captive red panda (Ailurus fulgens) that was found lethargic and anorectic. She was moved to the quarantine area for daily treatment with 50?mg of Cefpodoxime Proxetil. During the three-day treatment, she did not eat or defecate, and then died. Clinical hematology revealed the values of neutrophils, alanine aminotransferase (ALT), aspartate aminotransferase (AST) and blood urea nitrogen (BUN) were significantly higher. Histological analysis demonstrated major pathological damage in the kidneys, liver and lungs, characterized by hyperemia, parenchymal cell degeneration and necrosis and inflammatory cell infiltration which were predominantly neutrophilic. A bacterial strain confirmed as Escherichia coli was isolated post mortem. Whole genome sequencing of the E. coli showed the complete genome size was 4.99 Mbp. PapA, PapC, OmpA, OmpU and other virulence factors which specific to Uropathogenic Escherichia coli (UPEC) were found in the isolate. Among the virulence factors, P pili, type I pili and related factors of the iron uptake system were associated with nephrotoxicity. CONCLUSION:The red panda died of bacterial infection caused by an uropathogenic strain of Escherichia coli. The pathogenic mechanisms of the strain are closely related to the expression of specific virulence genes.
Project description:We announce the availability of the 5.023-Mbp high-quality draft assembly of the Escherichia coli strain Nissle 1917 (serovar O6:K5:H1) genome. Short genomic segments from this important probiotic strain have been available in public databases, but the full genome sequence has remained inaccessible. Thus, high-coverage, whole genome sequencing of E. coli Nissle 1917 is presented herein. Reannotation and metabolic reconstruction will enable comparative genomics analysis and model-guided predictions of genetic manipulations leading to increased production of the K5 capsular polysaccharide known as N-acetyl heparosan, a precursor to the anticoagulant pharmaceutical heparin.
Project description:Escherichia coli BW25113 is the parent strain of the Keio collection comprising nearly 4,000 single-gene deletion mutants. We report the complete 4,631,469-bp genome sequence of this strain and the key variations from the type strain E. coli MG1655.
Project description:The ability of <i>Escherichia coli</i> to tolerate acid stress is important for its survival and colonization in the human digestive tract. Here, we performed adaptive laboratory evolution of the laboratory strain <i>E. coli</i> K-12 MG1655 at pH 5.5 in glucose minimal medium. After 800 generations, six independent populations under evolution had reached 18.0?% higher growth rates than their starting strain at pH 5.5, while maintaining comparable growth rates to the starting strain at pH 7. We characterized the evolved strains and found that: (1) whole genome sequencing of isolated clones from each evolved population revealed mutations in <i>rpoC</i> appearing in five of six sequenced clones; and (2) gene expression profiles revealed different strategies to mitigate acid stress, which are related to amino acid metabolism and energy production and conversion. Thus, a combination of adaptive laboratory evolution, genome resequencing and expression profiling revealed, on a genome scale, the strategies that <i>E. coli</i> uses to mitigate acid stress.
Project description:Escherichia coli is one of the common inhabitants of the mammalian gastrointestinal track. We isolated a strain from an ob/ob mouse and performed whole-genome sequencing, which yielded a chromosome of ~5.1 Mb and three plasmids of ~160 kb, ~6 kb, and ~4 kb.
Project description:Escherichia coli (E. coli) amine oxidase (ECAO) encoded by tynA gene has been one of the model enzymes to study the mechanism of oxidative deamination of amines to the corresponding aldehydes by amine oxidases. The biological roles of ECAO have been less addressed. Therefore we have constructed a gene deletion Escherichia coli K-12 strain, E. coli tynA-, and used the microarray technique to address its function by comparing the total RNA gene expression to the one of the wt. Our results suggest that tynA is a reserve gene for stringent environmental conditions and its gene product ECAO a growth advantage compared to other bacteria due to H2O2 production. Overall design: The effect of deleting the expression of E. Coli amine oxidase by deleting tynA gene to the expression of other genes was done by comparing the knock out strain to wild type strain in different time points.
Project description:BACKGROUND: A large-scale Escherichia coli O104:H4 outbreak occurred in Germany from May to July 2011, causing numerous cases of hemolytic-uremic syndrome (HUS) and deaths. Genomes of ten outbreak isolates and a historical O104:H4 strain isolated in 2001 were sequenced using different new generation sequencing platforms. Phylogenetic analyses were performed using various approaches which either are not genome-wide or may be subject to errors due to poor sequence alignment. Also, detailed pathogenicity analyses on the 2001 strain were not available. FINDINGS: We reconstructed the phylogeny of E. coli using the genome-wide and alignment-free feature frequency profile method and revealed the 2001 strain to be the closest relative to the 2011 outbreak strain among all available E. coli strains at present and confirmed findings from previous alignment-based phylogenetic studies that the HUS-causing O104:H4 strains are more closely related to typical enteroaggregative E. coli (EAEC) than to enterohemorrhagic E. coli. Detailed re-examination of pathogenicity-related virulence factors and secreted proteins showed that the 2001 strain possesses virulence factors shared between typical EAEC and the 2011 outbreak strain. CONCLUSIONS: Our study represents the first attempt to elucidate the whole-genome phylogeny of the 2011 German outbreak using an alignment-free method, and suggested a direct line of ancestry leading from a putative EAEC-like ancestor through the 2001 strain to the 2011 outbreak strain.