enterohemorrhagic E. coli

(noun)

strains of the bacterium Escherichia coli that, when infecting humans, have been linked with the severe complication hemolytic-uremic syndrome

Related Terms

Examples of enterohemorrhagic E. coli in the following topics:

  • Penetrating Host Defenses

    • Escherichia coli (E. coli) is a bacterium that lives in the colon.
    • An example is E. coli O157:H7 .
    • Topographical images of colonies of E. coli O157:H7 strains (A) 43895OW (curli non-producing) and (B) 43895OR (curli producing) grown on agar for 48 h at 28°C.
    • Escherichia coli O157:H7 is an enterohemorrhagic strain of the bacterium Escherichia coli and a cause of food borne illness.

  • Pathogenic Escherichia coli

    • Escherichia coli (E. coli) is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms (endotherms).
    • In humans and in domestic animals, virulent strains of E. coli can cause various diseases.
    • Certain strains of E. coli produce potentially lethal toxins.
    • Transmission of pathogenic E. coli often occurs via fecal–oral transmission.
    • However, the antibiotic sensitivities of different strains of E. coli vary widely.

  • Hosts for Cloning Vectors

    • The majority of molecular cloning experiments begin with a laboratory strain of the bacterium E. coli (Escherichia coli) as the host.
    • A very large number of host organisms and molecular cloning vectors are in use, but the great majority of molecular cloning experiments begin with a laboratory strain of the bacterium E. coli (Escherichia coli) and a plasmid cloning vector.
    • E. coli and plasmid vectors are in common use because they are technically sophisticated, versatile, widely available, and offer rapid growth of recombinant organisms with minimal equipment.
    • Domain: Bacteria, Kingdom: Eubacteria, Phylum: Proteobacteria, Class: Gammaproteobacteria, Order: Enterobacteriales, Family: Enterobacteriaceae, Genus: Escherichia, Species: E. coli.

  • Normal Microbiota and Host Relationships

    • An example of our bacterial microbiota is E. coli .
    • Many people think of E. coli as the bacteria that makes you sick; however while it has that capacity, it can also remain dormant and benign in your gastrointestinal tract for your entire life.
    • All humans actually acquire E. coli shortly after birth with the intake of food or water.
    • This is a magnified view of Escherichia coli (or E. coli).

  • Detecting Acid and Gas Production

    • When cultured on an EMB (eosin methylene blue) plate, a positive result for E. coli is metallic green colonies on a dark purple media.
    • Some strains of E. coli can cause serious illness in humans .
    • Sorbitol MacConkey agar is a variant of the traditional MacConkey commonly used in the detection of E. coli O157:H7 .
    • E. coli O157:H7 differs from most other strains of E. coli in being unable to ferment sorbitol.
    • Most strains of E. coli ferment sorbitol to produce acid: E. coli O157:H7 can not ferment sorbitol, so this strain uses peptone to grow.

  • Bacterial Foodborne Diseases

    • The raw spinach outbreak in 2006 was produced by the bacterium E. coli serotype O157:H7.
    • Most E. coli are not particularly dangerous to humans, but serotype O157:H7 can cause bloody diarrhea and is potentially fatal.
    • A deadly outbreak in Germany in 2010 was caused by E. coli contamination of vegetable sprouts .
    • (a) Vegetable sprouts grown at an organic farm were the cause of an (b) E. coli outbreak that killed 32 people and sickened 3,800 in Germany in 2011.
    • The strain responsible, E. coli O104:H4, produces Shiga toxin, a substance that inhibits protein synthesis in the host cell.

  • The trp Operon: A Repressor Operon

    • Bacteria such as E. coli need amino acids to survive.
    • Tryptophan is one such amino acid that E. coli can ingest from the environment.
    • E. coli can also synthesize tryptophan using enzymes that are encoded by five genes.
    • If tryptophan is present in the environment, then E. coli does not need to synthesize it; the switch controlling the activation of the genes in the trp operon is turned off.
    • The five genes that are needed to synthesize tryptophan in E. coli are located next to each other in the trp operon.

  • Catabolite Activator Protein (CAP): An Activator Regulator

    • When glucose levels decline in E. coli, catabolite activator protein (CAP) is bound by cAMP to promote transcription of the lac operon.
    • For example, when glucose is scarce, E. coli bacteria can turn to other sugar sources for fuel.
    • The cAMP molecule is a signaling molecule that is involved in glucose and energy metabolism in E. coli.
    • When glucose levels fall, E. coli may use other sugars for fuel, but must transcribe new genes to do so.

  • Virulent Bacteriophages and T4

    • T-4 bacteriophage is a virulent bacteriophage that infects E. coli bacteria; virulent bacteriophages have a lytic life cycle.
    • T-4 bacteriophage is a bacteriophage that infects E. coli bacteria.
    • The T4 Phage initiates an E. coli infection by recognizing cell surface receptors of the host with its long tail fibers (LTF).
    • This unravels the short tail fibers (STF) that bind irreversibly to the E. coli cell surface.
    • The remaining part of the membrane is degraded and then DNA from the head of the phage can travel through the tail tube and enter the E. coli.

  • Mammalian Gene Expression in Bacteria

    • A DNA sequence for a protein of interest could be cloned or subcloned into a high copy-number plasmid containing the lac promoter, which is then transformed into the bacterium Escherichia coli.
    • For example, common bacterial hosts are E.coli and B. subtilis.
    • With E. coli, DNA is normally introduced in a plasmid expression vector.
    • The techniques for overexpression in E. coli work by increasing the number of copies of the gene or increasing the binding strength of the promoter region so as to assist transcription.
    • E. coli is one of the most popular hosts for artificial gene expression.