Diarrheagenic Escherichia coli are a diverse group of E. coli that are classified into 5 major pathotypes which can cause intestinal infection and diarrhea. Transmission is often through the fecal–oral route via the consumption of contaminated food or water. Pathogenesis varies based on the strain, but it can include toxin production, invasion of the mucosal surface, and adhesion Adhesion The process whereby platelets adhere to something other than platelets, e.g., collagen; basement membrane; microfibrils; or other 'foreign' surfaces. Coagulation Studies with alteration of enterocyte structure. Noninvasive disease tends to present with watery diarrhea Diarrhea Diarrhea is defined as ≥ 3 watery or loose stools in a 24-hour period. There are a multitude of etiologies, which can be classified based on the underlying mechanism of disease. The duration of symptoms (acute or chronic) and characteristics of the stools (e.g., watery, bloody, steatorrheic, mucoid) can help guide further diagnostic evaluation. Diarrhea, while invasive infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease cause bloody diarrhea Diarrhea Diarrhea is defined as ≥ 3 watery or loose stools in a 24-hour period. There are a multitude of etiologies, which can be classified based on the underlying mechanism of disease. The duration of symptoms (acute or chronic) and characteristics of the stools (e.g., watery, bloody, steatorrheic, mucoid) can help guide further diagnostic evaluation. Diarrhea. The diagnosis can be established with PCR PCR Polymerase chain reaction (PCR) is a technique that amplifies DNA fragments exponentially for analysis. The process is highly specific, allowing for the targeting of specific genomic sequences, even with minuscule sample amounts. The PCR cycles multiple times through 3 phases: denaturation of the template DNA, annealing of a specific primer to the individual DNA strands, and synthesis/elongation of new DNA molecules. Polymerase Chain Reaction (PCR). Management generally consists of supportive therapy (fluids and electrolytes Electrolytes Electrolytes are mineral salts that dissolve in water and dissociate into charged particles called ions, which can be either be positively (cations) or negatively (anions) charged. Electrolytes are distributed in the extracellular and intracellular compartments in different concentrations. Electrolytes are essential for various basic life-sustaining functions. Electrolytes). Antibiotics are reserved for severe or persistent infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease and are contraindicated with enterohemorrhagic E. coli because of the risk of hemolytic uremic syndrome Hemolytic uremic syndrome A syndrome that is associated with microvascular diseases of the kidney, such as renal cortical necrosis. It is characterized by hemolytic anemia; thrombocytopenia; and acute renal failure. Hypocoagulable Conditions.
Last updated: 8 Jun, 2022
Scanning electron microscope image of enterotoxigenic Escherichia coli Escherichia coli The gram-negative bacterium Escherichia coli is a key component of the human gut microbiota. Most strains of E. coli are avirulent, but occasionally they escape the GI tract, infecting the urinary tract and other sites. Less common strains of E. coli are able to cause disease within the GI tract, most commonly presenting as abdominal pain and diarrhea. Escherichia coli
Image: “Under an extremely high magnification of 44, 818X, twice that of PHIL 10574 and 10575, this scanning electron microscopic (SEM) image revealed some of the morphologic details displayed by a single Gram-negative, rod-shaped, Escherichia coli Escherichia coli The gram-negative bacterium Escherichia coli is a key component of the human gut microbiota. Most strains of E. coli are avirulent, but occasionally they escape the GI tract, infecting the urinary tract and other sites. Less common strains of E. coli are able to cause disease within the GI tract, most commonly presenting as abdominal pain and diarrhea. Escherichia coli bacterium.” by Janice Haney Carr. License: Public DomainThe following strains of E. coli are diarrheagenic:
Pathogen | Invasive? | Toxin? | Type of diarrhea Diarrhea Diarrhea is defined as ≥ 3 watery or loose stools in a 24-hour period. There are a multitude of etiologies, which can be classified based on the underlying mechanism of disease. The duration of symptoms (acute or chronic) and characteristics of the stools (e.g., watery, bloody, steatorrheic, mucoid) can help guide further diagnostic evaluation. Diarrhea |
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ETEC | No |
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EPEC | No | No |
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EAEC EAEC Escherichia coli | No |
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EIEC EIEC Escherichia coli | Yes |
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EHEC | Yes | Shiga toxin |
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Enterotoxigenic E. coli is a noninvasive pathogen. It uses fimbrial adhesins to bind BIND Hyperbilirubinemia of the Newborn enterocytes in the small intestine Small intestine The small intestine is the longest part of the GI tract, extending from the pyloric orifice of the stomach to the ileocecal junction. The small intestine is the major organ responsible for chemical digestion and absorption of nutrients. It is divided into 3 segments: the duodenum, the jejunum, and the ileum. Small Intestine: Anatomy and produces the following enterotoxins:
Enterotoxigenic
Escherichia coli
Escherichia coli
The gram-negative bacterium Escherichia coli is a key component of the human gut microbiota. Most strains of E. coli are avirulent, but occasionally they escape the GI tract, infecting the urinary tract and other sites. Less common strains of E. coli are able to cause disease within the GI tract, most commonly presenting as abdominal pain and diarrhea.
Escherichia coli (ETEC) pathogenesis:
ETEC attaches to enterocytes via
colonization
Colonization
Bacteriology factor
antigen
Antigen
Substances that are recognized by the immune system and induce an immune reaction.
Vaccination (CFA; fimbrial adhesin). The heat-stable (ST)
enterotoxin
Enterotoxin
Substances that are toxic to the intestinal tract causing vomiting, diarrhea, etc. ; most common enterotoxins are produced by bacteria.
Diarrhea causes cyclic
guanosine monophosphate
Guanosine monophosphate
A guanine nucleotide containing one phosphate group esterified to the sugar moiety and found widely in nature.
Purine and Pyrimidine Metabolism (
cGMP
cGMP
Guanosine cyclic 3.
Phosphodiesterase Inhibitors) accumulation in cells and
secretion
Secretion
Coagulation Studies of fluid and
electrolytes
Electrolytes
Electrolytes are mineral salts that dissolve in water and dissociate into charged particles called ions, which can be either be positively (cations) or negatively (anions) charged. Electrolytes are distributed in the extracellular and intracellular compartments in different concentrations. Electrolytes are essential for various basic life-sustaining functions.
Electrolytes into the intestinal lumen. The heat-labile (LT)
enterotoxin
Enterotoxin
Substances that are toxic to the intestinal tract causing vomiting, diarrhea, etc. ; most common enterotoxins are produced by bacteria.
Diarrhea acts like
cholera toxin
Cholera toxin
An enterotoxin from Vibrio cholerae. It consists of two major protomers, the heavy (h) or a subunit and the B protomer which consists of 5 light (l) or B subunits. The catalytic a subunit is proteolytically cleaved into fragments a1 and a2. The a1 fragment is a mono(adp-ribose) transferase. The B protomer binds cholera toxin to intestinal epithelial cells, and facilitates the uptake of the a1 fragment. The a1 catalyzed transfer of adp-ribose to the alpha subunits of heterotrimeric g proteins activates the production of cyclic amp. Increased levels of cyclic amp are thought to modulate release of fluid and electrolytes from intestinal crypt cells.
Vibrio, which increases cyclic
adenosine monophosphate
Adenosine monophosphate
Adenine nucleotide containing one phosphate group esterified to the sugar moiety in the 2′-, 3′-, or 5′-position.
Purine and Pyrimidine Metabolism (
cAMP
cAMP
An adenine nucleotide containing one phosphate group which is esterified to both the 3′- and 5′-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and acth.
Phosphodiesterase Inhibitors) by activating adenylyl cyclase (AC). The general effect is water and
chloride
Chloride
Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.
Electrolytes hypersecretion and inhibited
sodium reabsorption
Sodium reabsorption
Tubular System. Noninvasive enterotoxins remain within the intestinal lumen and do not invade the epithelial cells.
GC:
guanylyl cyclase
Guanylyl cyclase
A mammalian enzyme composed of a heterodimer of alpha and beta subunits. Each subunit consists of four domains; N-terminal HNOX domain, PAS-like domain, a coiled-coil domain, and a C-terminal catalytic domain. All four domains are homologous proteins with a similar conformation of functional domains. Soluble guanylate cyclase catalyzes the formation of cyclic GMP from GTP, and is a key enzyme of the nitric oxide signaling pathway involved in the regulation of a variety of biological and physiological processes in mammals.
Vascular Resistance, Flow, and Mean Arterial Pressure
LTA: A subunit of the
heat-labile enterotoxin
Heat-labile enterotoxin
Escherichia coli
This disease is self-limited; therefore, a diagnostic workup is not usually needed. However, ETEC can be diagnosed by identifying LT or ST genes Genes A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. DNA Types and Structure on PCR PCR Polymerase chain reaction (PCR) is a technique that amplifies DNA fragments exponentially for analysis. The process is highly specific, allowing for the targeting of specific genomic sequences, even with minuscule sample amounts. The PCR cycles multiple times through 3 phases: denaturation of the template DNA, annealing of a specific primer to the individual DNA strands, and synthesis/elongation of new DNA molecules. Polymerase Chain Reaction (PCR) for individuals with severe disease.
Enteropathogenic
Escherichia coli
Escherichia coli
The gram-negative bacterium Escherichia coli is a key component of the human gut microbiota. Most strains of E. coli are avirulent, but occasionally they escape the GI tract, infecting the urinary tract and other sites. Less common strains of E. coli are able to cause disease within the GI tract, most commonly presenting as abdominal pain and diarrhea.
Escherichia coli (EPEC) pathogenesis:
EPEC uses
intimin
Intimin
Escherichia coli
adhesion
Adhesion
The process whereby platelets adhere to something other than platelets, e.g., collagen; basement membrane; microfibrils; or other ‘foreign’ surfaces.
Coagulation Studies molecules to adhere to the intestinal cells. Binding causes cell deformation (
brush border
Brush border
Tubular System degeneration and loss of microvilli). The characteristic effect of
attachment
Attachment
The binding of virus particles to virus receptors on the host cell surface, facilitating virus entry into the cell.
Virology and effacement is thought to be the primary cause of
diarrhea
Diarrhea
Diarrhea is defined as ≥ 3 watery or loose stools in a 24-hour period. There are a multitude of etiologies, which can be classified based on the underlying mechanism of disease. The duration of symptoms (acute or chronic) and characteristics of the stools (e.g., watery, bloody, steatorrheic, mucoid) can help guide further diagnostic evaluation.
Diarrhea.
Enteropathogenic E. coli can be diagnosed by identifying specific genes Genes A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. DNA Types and Structure using PCR PCR Polymerase chain reaction (PCR) is a technique that amplifies DNA fragments exponentially for analysis. The process is highly specific, allowing for the targeting of specific genomic sequences, even with minuscule sample amounts. The PCR cycles multiple times through 3 phases: denaturation of the template DNA, annealing of a specific primer to the individual DNA strands, and synthesis/elongation of new DNA molecules. Polymerase Chain Reaction (PCR).
Enteroaggregative E. coli is most commonly associated with persistent diarrhea Diarrhea Diarrhea is defined as ≥ 3 watery or loose stools in a 24-hour period. There are a multitude of etiologies, which can be classified based on the underlying mechanism of disease. The duration of symptoms (acute or chronic) and characteristics of the stools (e.g., watery, bloody, steatorrheic, mucoid) can help guide further diagnostic evaluation. Diarrhea in:
The diagnosis of EAEC EAEC Escherichia coli can be made by identifying specific genes Genes A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. DNA Types and Structure using PCR PCR Polymerase chain reaction (PCR) is a technique that amplifies DNA fragments exponentially for analysis. The process is highly specific, allowing for the targeting of specific genomic sequences, even with minuscule sample amounts. The PCR cycles multiple times through 3 phases: denaturation of the template DNA, annealing of a specific primer to the individual DNA strands, and synthesis/elongation of new DNA molecules. Polymerase Chain Reaction (PCR).
Enteroinvasive E. coli presents very similarly to shigellosis Shigellosis Shigella and can be severe.
The diagnosis of EIEC EIEC Escherichia coli can be made by identifying specific genes Genes A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. DNA Types and Structure using PCR PCR Polymerase chain reaction (PCR) is a technique that amplifies DNA fragments exponentially for analysis. The process is highly specific, allowing for the targeting of specific genomic sequences, even with minuscule sample amounts. The PCR cycles multiple times through 3 phases: denaturation of the template DNA, annealing of a specific primer to the individual DNA strands, and synthesis/elongation of new DNA molecules. Polymerase Chain Reaction (PCR).
Enterohemorrhagic E. coli results in clinical manifestations through the production of shiga toxin:
The diagnosis of EHEC is made by identifying: