scholarly journals Enteroaggregative Escherichia coli: epidemiology, virulence and detection

2007 ◽  
Vol 56 (1) ◽  
pp. 4-8 ◽  
Author(s):  
Andrej Weintraub
Keyword(s):  
Escherichia Coli ◽  
Tissue Culture ◽  
Watery Diarrhoea ◽  
Biological Assays ◽  
E Coli ◽  
The Past ◽  
Sporadic Cases ◽  
Trained Staff ◽  
Definition Of ◽  
Specific Virulence

Enteroaggregative Escherichia coli (EAEC) is a subgroup of diarrhoeagenic E. coli (DEC) that during the past decade has received increasing attention as a cause of watery diarrhoea, which is often persistent. EAEC have been isolated from children and adults worldwide. As well as sporadic cases, outbreaks of EAEC-caused diarrhoea have been described. The definition of EAEC is the ability of the micro-organism to adhere to epithelial cells such as HEp-2 in a very characteristic ‘stacked-brick’ pattern. Although many studies searching for specific virulence factor(s) unique for this category of DEC have been published it is still unknown why the EAEC cause persistent diarrhoea. In addition, the aggregative property of EAEC causes a lot of problems in serotyping due to the cells auto-agglutinating. The gold standard for identification of EAEC includes isolation of the agent and an adherence assay using tissue culture, viz. HEp-2 cells. This assay is in most cases reliable; however, emergence of ‘atypical’ EAEC has been described in several publications. In addition, the HEp-2 assay is time consuming, demands a tissue culture lab and trained staff. Several molecular biological assays have been described, however, none show 100 % specificity.

scholarly journals Autotransporter Protein-Encoding Genes of Diarrheagenic Escherichia coli Are Found in both Typical and Atypical Enteropathogenic E. coli Strains

2012 ◽  
Vol 79 (1) ◽  
pp. 411-414 ◽  
Author(s):  
Afonso G. Abreu ◽  
Vanessa Bueris ◽  
Tatiane M. Porangaba ◽  
Marcelo P. Sircili ◽  
Fernando Navarro-Garcia ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Content Type ◽  
E Coli ◽  
Diarrheagenic Escherichia Coli ◽  
Virulence Markers ◽  
Protein Encoding ◽  
Encoding Genes ◽  
Specific Virulence

ABSTRACTAutotransporter (AT) protein-encoding genes of diarrheagenicEscherichia coli(DEC) pathotypes (cah,eatA,ehaABCDJ,espC,espI,espP,pet,pic,sat, andtibA) were detected in typical and atypical enteropathogenicE. coli(EPEC) in frequencies between 0.8% and 39.3%. Although these ATs have been described in particular DEC pathotypes, their presence in EPEC indicates that they should not be considered specific virulence markers.

Spheroplasts of enteropathogenic Escherichia coli. I. Biological characteristics

1968 ◽  
Vol 14 (6) ◽  
pp. 675-678 ◽  
Author(s):  
B. Diena ◽  
R. Wallace ◽  
L. Greenberg
Keyword(s):  
Escherichia Coli ◽  
Tissue Culture ◽  
Biological Characteristics ◽  
Enteropathogenic Escherichia Coli ◽  
E Coli ◽  
O Antigen ◽  
Pathogenic Serotypes

The properties of glycine-induced spheroplasts of six pathogenic serotypes of E. coli were investigated. Fimbriae and flagella appeared to be only partially synthesized as was the somatic O antigen. Cytopathogenicity of these spheroplasts for tissue culture was reduced and the infection of the monolayers was retarded as compared with the normal bacillary forms. Sensitivity to phage was almost completely lost, suggesting that glycine had either interfered with the synthesis of phage receptors or had altered the mucopeptide layerwhich is the substrate for phage enzymes. Alternatively, the phage may become a prophage inside the spheroplast with the loss of virulence.

Introduction to the Food Safety Concerns of Verotoxin-Producing Escherichia coli

2003 ◽  
Vol 228 (4) ◽  
pp. 331-332 ◽  
Author(s):  
Hussein S. Hussein ◽  
Stanley T. Omaye
Keyword(s):  
Escherichia Coli ◽  
Food Safety ◽  
Safety Concern ◽  
Critical Evaluation ◽  
The United States ◽  
Global Perspective ◽  
E Coli ◽  
The Past ◽  
Food Borne Pathogens ◽  
Food Borne

Verotoxin-producing Escherichia coli (VTEC) have emerged in the past two decades as food-borne pathogens that can cause major outbreaks of human illnesses worldwide. The number of outbreaks has increased in recent years due to changes in food production and processing systems, eating habits, microbial adaptation, and methods of VTEC transmission. The human illnesses range from mild diarrhea to hemolytic uremic syndrome (HUS) that can lead to death. The VTEC outbreaks have been attributed to O157:H7 and non-O157:H7 serotypes of E. coli. These E. coli serotypes include motile (e.g., O26:H11 and O104:H21) and nonmotile (e.g., O111:H–,0145:H–, and O157:H–) strains. In the United States, E. coli O157:H7 has been the major cause of VTEC outbreaks. Worldwide, however, non-O157:H7 VTEC (e.g., members of the 026, O103, O111, O118, O145, and O166 serogroups) have caused approximately 30% of the HUS cases in the past decade. Because large numbers of the VTEC outbreaks have been attributed to consumption of ruminant products (e.g., ground beef), cattle and sheep are considered reservoirs of these food-borne pathogens. Because of the food safety concern of VTEC, a global perspective on this problem is addressed (Exp Biol Med Vol. 228, No. 4). The first objective was to evaluate the known non-O157:H7 VTEC strains and the limitations associated with their detection and characterization. The second objective was to identify the VTEC serotypes associated with outbreaks of human illnesses and to provide critical evaluation of their virulence. The third objective was to determine the rumen effect on survival of E. coli O157:H7 as a VTEC model. The fourth objective was to explore the role of intimins in promoting attaching and effacing lesions in humans. Finally, the ability of VTEC to cause persistent infections in cattle was evaluated.

scholarly journals Genotypic and Phenotypic Traits That Distinguish Neonatal Meningitis-Associated Escherichia coli from Fecal E. coli Isolates of Healthy Human Hosts

2012 ◽  
Vol 78 (16) ◽  
pp. 5824-5830 ◽  
Author(s):  
Catherine M. Logue ◽  
Curt Doetkott ◽  
Paul Mangiamele ◽  
Yvonne M. Wannemuehler ◽  
Timothy J. Johnson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Phylogenetic Group ◽  
Neonatal Meningitis ◽  
Phenotypic Traits ◽  
Healthy Human ◽  
Content Type ◽  
Plasmid Content ◽  
E Coli ◽  
Healthy Humans ◽  
Definition Of

ABSTRACTNeonatal meningitisEscherichia coli(NMEC) is one of the top causes of neonatal meningitis worldwide. Here, 85 NMEC and 204 fecalE. coliisolates from healthy humans (HFEC) were compared for possession of traits related to virulence, antimicrobial resistance, and plasmid content. This comparison was done to identify traits that typify NMEC and distinguish it from commensal strains to refine the definition of the NMEC subpathotype, identify traits that might contribute to NMEC pathogenesis, and facilitate choices of NMEC strains for future study. A large number ofE. colistrains from both groups were untypeable, with the most common serogroups occurring among NMEC being O18, followed by O83, O7, O12, and O1. NMEC strains were more likely than HFEC strains to be assigned to the B2 phylogenetic group. Few NMEC or HFEC strains were resistant to antimicrobials. Genes that best discriminated between NMEC and HFEC strains and that were present in more than 50% of NMEC isolates were mainly from extraintestinal pathogenicE. coligenomic and plasmid pathogenicity islands. Several of these defining traits had not previously been associated with NMEC pathogenesis, are of unknown function, and are plasmid located. Several genes that had been previously associated with NMEC virulence did not dominate among the NMEC isolates. These data suggest that there is much about NMEC virulence that is unknown and that there are pitfalls to studying single NMEC isolates to represent the entire subpathotype.

scholarly journals Escherichia coli as a genetic tool

1985 ◽  
Vol 95 (3) ◽  
pp. 611-618
Author(s):  
Naomi Datta
Keyword(s):  
Escherichia Coli ◽  
Academic Research ◽  
Genetically Engineered ◽  
Cloning And Expression ◽  
Biological Research ◽  
New Techniques ◽  
E Coli ◽  
Genetic Tool ◽  
The Past ◽  
Made In

SUMMARYThe study of Escherichia coli and its plasmids and bacteriophages has provided a vast body of genetical information, much of it relevant to the whole of biology. This was true even before the development of the new techniques, for cloning and analysing DNA, that have revolutionized biological research during the past decade. Thousands of millions of dollars are now invested in industrial uses of these techniques, which all depend on discoveries made in the course of academic research on E. coli. Much of the background of knowledge necessary for the cloning and expression of genetically engineered information, as well as the techniques themselves, came from work with this organism.

scholarly journals Of the Morphogenes that Make a Ring, A Rod and a Sphere in Escherichia Coli

2007 ◽  
Vol 90 (2-3) ◽  
pp. 59-72 ◽  
Author(s):  
Medhatm Khattar ◽  
Issmat I. Kassem ◽  
Ziad W. El-Hajj
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Bacterial Cell ◽  
Bacterial Cell Division ◽  
Antibacterial Compounds ◽  
E Coli ◽  
The Past ◽  
New Knowledge ◽  
Fundamental Process ◽  
Simple Question

In 1993, William Donachie wrote “The success of molecular genetics in the study of bacterial cell division has been so great that we find ourselves, armed with much greater knowledge of detail, confronted once again with the same naive questions that we set to answer in the first place”1. Indeed, attempts to answer the apparently simple question of how a bacterial cell divides have led to a wealth of new knowledge, in particular over the past decade and a half. And while some questions have been answered to a great extent since the early reports of isolation of division mutants of Escherichia coli2,3, some key pieces of the puzzle remain elusive. In addition to it being a fundamental process in bacteria that merits investigation in its own right, studying the process of cell division offers an abundance of new targets for the development of new antibacterial compounds that act directly against key division proteins and other components of the cytoskeleton, which are encoded by the morphogenes of E. coli4. This review aims to present the reader with a snapshot summary of the key players in E. coli morphogenesis with emphasis on cell division and the rod to sphere transition.

Etude taxonomique d'entérobactéries appartenant ou apparentées à l'espèce Escherichia coli

1981 ◽  
Vol 27 (1) ◽  
pp. 98-106 ◽  
Author(s):  
F. Gavini ◽  
D. Izard ◽  
P. A. Trinel ◽  
B. Lefebvre ◽  
H. Leclerc
Keyword(s):  
Escherichia Coli ◽  
Numerical Analysis ◽  
Dna Hybridization ◽  
Dna Relatedness ◽  
E Coli ◽  
Definition Of

Phenetic (numerical analysis) and genetic (DNA–DNA hybridization) studies were carried out on strains belonging or related to the species Escherichia coli. They have shown the diversity of its phenotypes, by the presence of plasmidic characters (citrate+, urease+, H2S+, tetrathionate reductase+, raffinose+, and saccharose+). New strains related phenetically to E. coli are also individualized. They showed less than 30% DNA relatedness with E. coli. A new definition of E. coli is presented.

scholarly journals rhs Genes Are Potential Markers for Multilocus Sequence Typing of Escherichia coli O157:H7 Strains

2009 ◽  
Vol 75 (18) ◽  
pp. 5853-5862 ◽  
Author(s):  
K. Liu ◽  
S. J. Knabel ◽  
E. G. Dudley
Keyword(s):  
Escherichia Coli ◽  
Phylogenetic Analysis ◽  
Multilocus Sequence Typing ◽  
Sequence Variation ◽  
Escherichia Coli O157 ◽  
Positive Selection Pressure ◽  
E Coli ◽  
The Past ◽  
Unique Markers ◽  
Sequence Types

ABSTRACT DNA sequence-based molecular subtyping methods such as multilocus sequence typing (MLST) are commonly used to generate phylogenetic inferences for monomorphic pathogens. The development of an effective MLST scheme for subtyping Escherichia coli O157:H7 has been hindered in the past due to the lack of sequence variation found within analyzed housekeeping and virulence genes. A recent study suggested that rhs genes are under strong positive selection pressure, and therefore in this study we analyzed these genes within a diverse collection of E. coli O157:H7 strains for sequence variability. Eighteen O157:H7 strains from lineages I and II and 15 O157:H7 strains from eight clades were included. Examination of these rhs genes revealed 44 polymorphic loci (PL) and 10 sequence types (STs) among the 18 lineage strains and 280 PL and 12 STs among the 15 clade strains. Phylogenetic analysis using rhs genes generally grouped strains according to their known lineage and clade classifications. These findings also suggested that O157:H7 strains from clades 6 and 8 fall into lineage I/II and that strains of clades 1, 2, 3, and 4 fall into lineage I. Additionally, unique markers were found in rhsA and rhsJ that might be used to define clade 8 and clade 6. Therefore, rhs genes may be useful markers for phylogenetic analysis of E. coli O157:H7.

scholarly journals Escherichia coli Strains with Virulent Factors Typical for Uropathogens were Isolated from Sinuses from Patients with Chronic Rhinosinusitis—Case Report

Pathogens ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 318
Author(s):  
Beata Krawczyk ◽  
Michał Michalik ◽  
Magdalena Fordon ◽  
Magdalena Wysocka ◽  
Alfred Samet ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Chronic Rhinosinusitis ◽  
Virulence Factors ◽  
Previous Treatment ◽  
Uptake System ◽  
E Coli ◽  
Fitness Advantage ◽  
Pcr Method ◽  
The Rich ◽  
Specific Virulence

Escherichia coli were isolated from three patients with chronic rhinosinusitis (CRS) by intraoperative sinus tissue biopsy. Taking into account the unusual replicative niche and previous treatment failures, it was decided to focus on the virulence and drug resistance of these bacteria. The strains turned out to be multi-sensitive, but the rich virulence factors profile of bacteria typical for phylogenetic group B2 deserved attention. Tests were carried out for the presence of 32 genes using the PCR method. Particularly noteworthy are the toxins Cnf-1, HlyA, Usp—an extensive iron uptake system (enterobactin, salmochelin, yersiniabactin and outer membrane hemin receptor ChuA)—SPATE autotransporters such as vat and pic, Ag43 autoaggregative protein—important for biofilm formation—and TosA/B which enhance the fitness of E.coli. All these virulence factors are identified predominantly in UPEC strains and provide a fitness advantage during colonization of the sinuses. Patients with CRS should be asked for past or present UTI. The specific virulence factors of E. coli that facilitate the colonization of the GI tract and urinary tract may also favor the colonization of a new ecological niche (sinuses) as a result of microbial imbalance or dysbiosis.

scholarly journals ‘Super' or just ‘above average'? Supershedders and the transmission of Escherichia coli O157:H7 among feedlot cattle

2015 ◽  
Vol 12 (110) ◽  
pp. 20150446 ◽  
Author(s):  
Simon E. F. Spencer ◽  
Thomas E. Besser ◽  
Rowland N. Cobbold ◽  
Nigel P. French
Keyword(s):  
Escherichia Coli ◽  
Stocking Density ◽  
Preliminary Evidence ◽  
Feedlot Cattle ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Key Characteristics ◽  
Data Driven Approach ◽  
Definition Of

Supershedders have been suggested to be major drivers of transmission of Escherichia coli O157:H7 ( E. coli O157:H7) among cattle in feedlot environments, despite our relatively limited knowledge of the processes that govern periods of high shedding within an individual animal. In this study, we attempt a data-driven approach, estimating the key characteristics of high shedding behaviour, including effects on transmission to other animals, directly from a study of natural E. coli O157:H7 infection of cattle in a research feedlot, in order to develop an evidence-based definition of supershedding. In contrast to the hypothesized role of supershedders, we found that high shedding individuals only modestly increased the risk of transmission: individuals shedding over 10 3 cfu g −1 faeces were estimated to pose a risk of transmission only 2.45 times greater than those shedding below that level. The data suggested that shedding above 10 3 cfu g −1 faeces was the most appropriate definition of supershedding behaviour and under this definition supershedding was surprisingly common, with an estimated prevalence of 31.3% in colonized individuals. We found no evidence that environmental contamination by faeces of shedding cattle contributed to transmission over timescales longer than 3 days and preliminary evidence that higher stocking density increased the risk of transmission.

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