scholarly journals Extensive Genomic Diversity in Pathogenic Escherichia coli and Shigella Strains Revealed by Comparative Genomic Hybridization Microarray

2004 ◽  
Vol 186 (12) ◽  
pp. 3911-3921 ◽  
Author(s):  
Satoru Fukiya ◽  
Hiroshi Mizoguchi ◽  
Toru Tobe ◽  
Hideo Mori
Keyword(s):  
Escherichia Coli ◽  
Comparative Genomic Hybridization ◽  
Cell Envelope ◽  
Genome Structure ◽  
Genomic Diversity ◽  
Comparative Genomic ◽  
Genomic Hybridization ◽  
Phylogenic Tree ◽  
E Coli ◽  
K 12

ABSTRACT Escherichia coli, including the closely related genus Shigella, is a highly diverse species in terms of genome structure. Comparative genomic hybridization (CGH) microarray analysis was used to compare the gene content of E. coli K-12 with the gene contents of pathogenic strains. Missing genes in a pathogen were detected on a microarray slide spotted with 4,071 open reading frames (ORFs) of W3110, a commonly used wild-type K-12 strain. For 22 strains subjected to the CGH microarray analyses 1,424 ORFs were found to be absent in at least one strain. The common backbone of the E. coli genome was estimated to contain about 2,800 ORFs. The mosaic distribution of absent regions indicated that the genomes of pathogenic strains were highly diversified becasue of insertions and deletions. Prophages, cell envelope genes, transporter genes, and regulator genes in the K-12 genome often were not present in pathogens. The gene contents of the strains tested were recognized as a matrix for a neighbor-joining analysis. The phylogenic tree obtained was consistent with the results of previous studies. However, unique relationships between enteroinvasive strains and Shigella, uropathogenic, and some enteropathogenic strains were suggested by the results of this study. The data demonstrated that the CGH microarray technique is useful not only for genomic comparisons but also for phylogenic analysis of E. coli at the strain level.

scholarly journals Comparative Genomic Hybridization Detects Secondary Chromosomal Deletions in Escherichia coli K-12 MG1655 Mutants and Highlights Instability in the flhDC Region

2007 ◽  
Vol 189 (24) ◽  
pp. 8786-8792 ◽  
Author(s):  
Jon L. Hobman ◽  
Mala D. Patel ◽  
G. Aida Hidalgo-Arroyo ◽  
S. James L. Cariss ◽  
Matthew B. Avison ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Comparative Genomic Hybridization ◽  
Comparative Genomic ◽  
Deletion Mutants ◽  
Genomic Integrity ◽  
Genomic Hybridization ◽  
Genomic Deletions ◽  
Gene Knockouts ◽  
K 12 ◽  
Phenotypic Tests

ABSTRACT The use of whole-genome microarrays for monitoring mutagenized or otherwise engineered genetic derivatives is a potentially powerful tool for checking genomic integrity. Using comparative genomic hybridization of a number of unrelated, directed deletion mutants in Escherichia coli K-12 MG1655, we identified unintended secondary genomic deletions in the flhDC region in Δfnr, Δcrp, and ΔcreB mutants. These deletions were confirmed by PCR and phenotypic tests. Our findings show that nonmotile progeny are found in some MG1655 directed deletion mutants, and studies on the effects of gene knockouts should be viewed with caution when the mutants have not been screened for the presence of secondary deletions or confirmed by other methods.

scholarly journals Survey of Genomic Diversity among Enterococcus faecalis Strains by Microarray-Based Comparative Genomic Hybridization

2007 ◽  
Vol 73 (7) ◽  
pp. 2207-2217 ◽  
Author(s):  
Ågot Aakra ◽  
O. Ludvig Nyquist ◽  
Lars Snipen ◽  
Turid S. Reiersen ◽  
Ingolf F. Nes
Keyword(s):  
Enterococcus Faecalis ◽  
Comparative Genomic Hybridization ◽  
Antibiotic Resistance Genes ◽  
Genomic Diversity ◽  
Comparative Genomic ◽  
Mobile Dna ◽  
Genomic Hybridization ◽  
Promising Tool ◽  
Plasmid Genes ◽  
Harsh Conditions

ABSTRACT We have compared nine Enterococcus faecalis strains with E. faecalis V583 by comparative genomic hybridization using microarrays (CGH). The strains used in this study (the “test” strains) originated from various environments. CGH is a powerful and promising tool for obtaining novel information on genome diversity in bacteria. By CGH, one obtains clues about which genes are present or divergent in the strains, compared to a reference strain (here, V583). The information obtained by CGH is important from both ecological and systematic points of view. CGH of E. faecalis showed considerable diversity in gene content: Compared to V583, the percentage of divergent genes in the test strains varied from 15% to 23%, and 154 genes were divergent in all strains. The main variation was found in regions corresponding to exogenously acquired or mobile DNA in V583. Antibiotic resistance genes, virulence factors, and integrated plasmid genes dominated among the divergent genes. The strains examined showed various contents of genes corresponding to the pTEF1, pTEF2, and pTEF3 genes in V583. The extensive transport and metabolic capabilities of V583 appeared similar in the test strains; CGH indicated that the ability to transport and metabolize various carbohydrates was similar in the test strains (verified by API 50 CH assays). The contents of genes related to stress tolerance appeared similar in V583 and the nine test strains, supporting the view of E. faecalis as an organism able to resist harsh conditions.

scholarly journals Genomic Insights of Multidrug-Resistant Escherichia coli From Wastewater Sources and Their Association With Clinical Pathogens in South Africa

2021 ◽  
Vol 8 ◽  
Author(s):  
Joshua Mbanga ◽  
Daniel G. Amoako ◽  
Akebe L. K. Abia ◽  
Mushal Allam ◽  
Arshad Ismail ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Virulence Genes ◽  
Treatment Plant ◽  
Multidrug Resistant ◽  
Genomic Diversity ◽  
Health Concern ◽  
Comparative Genomic ◽  
Phylogenomic Analysis ◽  
E Coli ◽  
Wwtp Effluent

There is limited information on the comparative genomic diversity of antibiotic-resistant Escherichia coli from wastewater. We sought to characterize environmental E. coli isolates belonging to various pathotypes obtained from a wastewater treatment plant (WWTP) and its receiving waters using whole-genome sequencing (WGS) and an array of bioinformatics tools to elucidate the resistomes, virulomes, mobilomes, clonality, and phylogenies. Twelve multidrug-resistant (MDR) diarrheagenic E. coli isolates were obtained from the final effluent of a WWTP, and the receiving river upstream and downstream of the WWTP were sequenced on an Illumina MiSeq machine. The multilocus sequence typing (MLST) analysis revealed that multiple sequence types (STs), the most common of which was ST69 (n = 4) and ST10 (n = 2), followed by singletons belonging to ST372, ST101, ST569, ST218, and ST200. One isolate was assigned to a novel ST ST11351. A total of 66.7% isolates were positive for β-lactamase genes with 58.3% harboring the blaTEM1B gene and a single isolate the blaCTX−M−14 and blaCTX−M−55 extended-spectrum β-lactamase (ESBL) genes. One isolate was positive for the mcr-9 mobilized colistin resistance gene. Most antibiotic resistance genes (ARGs) were associated with mobile genetic support: class 1 integrons (In22, In54, In191, and In369), insertion sequences (ISs), and/or transposons (Tn402 or Tn21). A total of 31 virulence genes were identified across the study isolates, including those responsible for adhesion (lpfA, iha, and aggR), immunity (air, gad, and iss), and toxins (senB, vat, astA, and sat). The virulence genes were mostly associated with IS (IS1, IS3, IS91, IS66, IS630, and IS481) or prophages. Co-resistance to heavy metal/biocide, antibiotics were evident in several isolates. The phylogenomic analysis with South African E. coli isolates from different sources (animals, birds, and humans) revealed that isolates from this study mostly clustered with clinical isolates. Phylogenetics linked with metadata revealed that isolates did not cluster according to source but according to ST. The occurrence of pathogenic and MDR isolates in the WWTP effluent and the associated river is a public health concern.

scholarly journals The Pangenome Structure of Escherichia coli: Comparative Genomic Analysis of E. coli Commensal and Pathogenic Isolates

2008 ◽  
Vol 190 (20) ◽  
pp. 6881-6893 ◽  
Author(s):  
David A. Rasko ◽  
M. J. Rosovitz ◽  
Garry S. A. Myers ◽  
Emmanuel F. Mongodin ◽  
W. Florian Fricke ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Genome Sequencing ◽  
Genomic Analysis ◽  
Comparative Genomic Analysis ◽  
Genomic Diversity ◽  
Comparative Genomic ◽  
Whole Genome ◽  
E Coli ◽  
Important Group ◽  
Commensal Species

ABSTRACT Whole-genome sequencing has been skewed toward bacterial pathogens as a consequence of the prioritization of medical and veterinary diseases. However, it is becoming clear that in order to accurately measure genetic variation within and between pathogenic groups, multiple isolates, as well as commensal species, must be sequenced. This study examined the pangenomic content of Escherichia coli. Six distinct E. coli pathovars can be distinguished using molecular or phenotypic markers, but only two of the six pathovars have been subjected to any genome sequencing previously. Thus, this report provides a seminal description of the genomic contents and unique features of three unsequenced pathovars, enterotoxigenic E. coli, enteropathogenic E. coli, and enteroaggregative E. coli. We also determined the first genome sequence of a human commensal E. coli isolate, E. coli HS, which will undoubtedly provide a new baseline from which workers can examine the evolution of pathogenic E. coli. Comparison of 17 E. coli genomes, 8 of which are new, resulted in identification of ∼2,200 genes conserved in all isolates. We were also able to identify genes that were isolate and pathovar specific. Fewer pathovar-specific genes were identified than anticipated, suggesting that each isolate may have independently developed virulence capabilities. Pangenome calculations indicate that E. coli genomic diversity represents an open pangenome model containing a reservoir of more than 13,000 genes, many of which may be uncharacterized but important virulence factors. This comparative study of the species E. coli, while descriptive, should provide the basis for future functional work on this important group of pathogens.

scholarly journals Comparative Genomic Indexing Reveals the Phylogenomics of Escherichia coli Pathogens

2003 ◽  
Vol 71 (8) ◽  
pp. 4674-4683 ◽  
Author(s):  
Muna F. Anjum ◽  
Sacha Lucchini ◽  
Arthur Thompson ◽  
Jay C. D. Hinton ◽  
Martin J. Woodward
Keyword(s):  
Escherichia Coli ◽  
Diarrheal Disease ◽  
Comparative Genomic ◽  
E Coli ◽  
Food Borne ◽  
Typing Methods ◽  
K 12 ◽  
Genomic Indexing ◽  
Core Genes ◽  
Genomic Similarity

ABSTRACT The Escherichia coli O26 serogroup includes important food-borne pathogens associated with human and animal diarrheal disease. Current typing methods have revealed great genetic heterogeneity within the O26 group; the data are often inconsistent and focus only on verotoxin (VT)-positive O26 isolates. To improve current understanding of diversity within this serogroup, the genomic relatedness of VT-positive and -negative O26 strains was assessed by comparative genomic indexing. Our results clearly demonstrate that irrespective of virulence characteristics and pathotype designation, the O26 strains show greater genomic similarity to each other than to any other strain included in this study. Our data suggest that enteropathogenic and VT-expressing E. coli O26 strains represent the same clonal lineage and that VT-expressing E. coli O26 strains have gained additional virulence characteristics. Using this approach, we established the core genes which are central to the E. coli species and identified regions of variation from the E. coli K-12 chromosomal backbone.

Investigating the role of pneumococcal neuraminidase A activity in isolates from pneumococcal haemolytic uraemic syndrome

2013 ◽  
Vol 62 (11) ◽  
pp. 1735-1742 ◽  
Author(s):  
Andrew Smith ◽  
Calum Johnston ◽  
Donald Inverarity ◽  
Mary Slack ◽  
Gavin K. Paterson ◽  
...  
Keyword(s):  
Gene Expression ◽  
Young Children ◽  
Comparative Genomic Hybridization ◽  
Haemolytic Uraemic Syndrome ◽  
Genomic Diversity ◽  
Comparative Genomic ◽  
Genomic Hybridization ◽  
Neuraminidase Activity ◽  
Atypical Haemolytic Uraemic Syndrome ◽  
Significant Difference

Streptococcus pneumoniae diseases are a rare but increasingly recognized trigger of atypical haemolytic uraemic syndrome (HUS) in young children and associated with a higher mortality rate than diarrhoea-associated HUS. This study aimed to determine the importance of neuraminidase A (NanA) and genomic diversity in the pathogenesis of pneumococcal HUS (pHUS). We investigated the nanA gene sequence, gene expression, neuraminidase activity and comparative genomic hybridization of invasive pneumococcal disease (IPD) isolates from patients with pHUS and control strains matched by serotype and sequence type (ST), isolated from patients with IPD but not pHUS. The nanA sequence of 33 isolates was determined and mutations at 142 aa positions were identified. High levels of diversity were observed within the NanA protein, with mosaic blocks, insertions and repeat regions present. When comparing nanA allelic diversity with ST and disease profile in the isolates tested, nanA alleles clustered mostly by ST. No particular nanA allele was associated with pHUS. There was no significant difference in overall neuraminidase activity between pHUS isolates and controls when induced/uninduced with N-acetylneuraminic acid. Comparative genomic hybridization showed little difference in genetic content between the pHUS isolates and the controls. Results of gene expression studies identified 12 genes differentially regulated in all pHUS isolates compared with the control. Although neuraminidase enzyme activity may be important in pHUS progression and contribute to pathogenesis, the lack of a distinction between pHUS isolates and controls suggests that host factors, such as acquired abnormalities of the alternative complement cascade in young children, may play a more significant role in the outcome of pHUS.

scholarly journals Transcript Profiling and Inference of Escherichia coli K-12 ArcA Activity across the Range of Physiologically Relevant Oxygen Concentrations

2011 ◽  
Vol 286 (12) ◽  
pp. 10147-10154 ◽  
Author(s):  
Matthew D. Rolfe ◽  
Alex Ter Beek ◽  
Alison I. Graham ◽  
Eleanor W. Trotter ◽  
H. M. Shahzad Asif ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Envelope ◽  
Oxygen Availability ◽  
Two Component System ◽  
Transcriptional Responses ◽  
Environmental Signals ◽  
E Coli ◽  
Transcript Profiles ◽  
K 12 ◽  
First Time

Oxygen availability is the major determinant of the metabolic modes adopted by Escherichia coli. Although much is known about E. coli gene expression and metabolism under fully aerobic and anaerobic conditions, the intermediate oxygen tensions that are encountered in natural niches are understudied. Here, for the first time, the transcript profiles of E. coli K-12 across the physiologically significant range of oxygen availabilities are described. These suggested a progressive switch to aerobic respiratory metabolism and a remodeling of the cell envelope as oxygen availability increased. The transcriptional responses were consistent with changes in the abundance of cytochrome bd and bo′ and the outer membrane protein OmpW. The observed transcript and protein profiles result from changes in the activities of regulators that respond to oxygen itself or to metabolic and environmental signals that are sensitive to oxygen availability (aerobiosis). A probabilistic model (TFInfer) was used to predict the activity of the indirect oxygen-sensing two-component system ArcBA across the aerobiosis range. The model implied that the activity of the regulator ArcA correlated with aerobiosis but not with the redox state of the ubiquinone pool, challenging the idea that ArcA activity is inhibited by oxidized ubiquinone. The amount of phosphorylated ArcA correlated with the predicted ArcA activities and with aerobiosis, suggesting that fermentation product-mediated inhibition of ArcB phosphatase activity is the dominant mechanism for regulating ArcA activity under the conditions used here.

Properties of haemolysin E (HlyE) from a pathogenic Escherichia coli avian isolate and studies of HlyE export

Microbiology ◽  
2004 ◽  
Vol 150 (5) ◽  
pp. 1495-1505 ◽  
Author(s):  
Neil R. Wyborn ◽  
Angela Clark ◽  
Ruth E. Roberts ◽  
Stuart J. Jamieson ◽  
Svetomir Tzokov ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Blood Cells ◽  
Cell Envelope ◽  
Membrane Integrity ◽  
Intrinsic Property ◽  
E Coli ◽  
Pathogenic Escherichia Coli ◽  
Carboxyl Terminal ◽  
K 12

Haemolysin E (HlyE) is a novel pore-forming toxin first identified in Escherichia coli K-12. Analysis of the 3-D structure of HlyE led to the proposal that a unique hydrophobic β-hairpin structure (the β-tongue, residues 177–203) interacts with the lipid bilayer in target membranes. In seeming contradiction to this, the hlyE sequence from a pathogenic E. coli strain (JM4660) that lacks all other haemolysins has been reported to encode an Arg residue at position 188 that was difficult to reconcile with the proposed role of the β-tongue. Here it is shown that the JM4660 hlyE sequence encodes Gly, not Arg, at position 188 and that substitution of Gly188 by Arg in E. coli K-12 HlyE abolishes activity, emphasizing the importance of the head domain in HlyE function. Nevertheless, 76 other amino acid substitutions were confirmed compared to the HlyE protein of E. coli K-12. The JM4660 HlyE protein was dimeric, suggesting a mechanism for improving toxin solubility, and it lysed red blood cells from many species by forming 36–41 Å diameter pores. However, the haemolytic phenotype of JM4660 was found to be unstable due to defects in HlyE export, indicating that export of active HlyE is not an intrinsic property of the protein but requires additional components. TnphoA mutagenesis of hlyE shows that secretion from the cytoplasm to the periplasm does not require the carboxyl-terminal region of HlyE. Finally, disruption of genes associated with cell envelope function, including tatC, impairs HlyE export, indicating that outer membrane integrity is important for effective HlyE secretion.

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