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Type and morphology. E. coli is a gram-negative, facultative anaerobe, nonsporulating coliform bacterium. Cells are typically rod-shaped, and are about 2.0 μm long and 0.25–1.0 μm in diameter, with a cell volume of 0.6–0.7 μm 3.
- EPEC
Escherichia coli (/ ˌ ɛ ʃ ə ˈ r ɪ k i ə ˈ k oʊ l aɪ /...
- Entamoeba COLI
Entamoeba coli is a non-pathogenic species of Entamoeba that...
- Gram-negative
Microscopic image of gram-negative Pseudomonas aeruginosa...
- Enterobacteriaceae
Enterobacteriaceae is a large family of Gram-negative...
- Salmonella Enterica
Salmonella enterica (formerly Salmonella choleraesuis) is a...
- Facultative Anaerobic
Functions. Facultative anaerobes are able to grow in both...
- EPEC
- Escherichia Coli
- E. Coli Habitat
- Geographical Distribution of Escherichia Coli
- Reservoir, Source, and Transmission of Infection
- E.coli Morphology and Arrangement
- Biochemical Reactions
- Cell Wall Components and Antigenic Structure of Escherichia Coli
- Virulence Factors of Escherichia Coli
- Pathogenesis of E. Coli Infections
- Cultural Characteristics of E. Coli/E. Coli Colonies Morphology
Theodor Escherich first discovered E. coli, in 1885 after isolating it from the feces of newborns.Escherichia coli also termed E. coli, which is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus Escherichia.It is usually found in the lower intestine of warm-blooded organisms (endotherms).Most E. coli strains are harmless, however, some serotypes (EPEC, ETEC etc.) are responsible for serious food poisoning in their hosts. They also occasionally cause food contaminationincidents that...The availability of the nutrients within the intestine of host organisms is the main factor on which the niche of E. coli depends.The gastrointestinal (GI) tract of humans and many other warm-blooded animals is the primary habitat of E. coli.They can be found in the mucus or the epithelium on the wall of the intestine. Commonly they are found in the colon of the large intestine.They can form a mutual relationship with its host.Many strains of E. coli that cause diarrhoea largely affect populations in underdeveloped nations. Globally, the prevalence of these strains varies considerably.EPEC, EAEC, and DAEC are reported to be most prevalent in underdeveloped nations.ETEC is the leading cause of both traveler’s diarrhoea and infantile diarrhoea in impoverished and emerging nations.Each year, ETEC is responsible for over 600 million instances of diarrhoea and 700,000 fatalities in children under the age of five.With the exception of neonatal meningitis and gastroenteritis, the majority of E. coli infections are endogenous.The infection is produced by the usual microbial flora of the patient, which includes E. coli.These bacteria cause infections, such as a urinary tract infection (UTI), when a patient’s defences are weakened or when personal hygiene is inadequate.In places with low sanitation, E. coli-caused diarrhoea is prevalent, and infections are transmitted from outside the host.E.coli is a gram-negative (-ve) bacteria.These are straight, rod shaped (bacillus) bacterium.They are arranged singly or in pairs.Their size is about 1–3 µm × 0.4–0.7 µm (micrometer).E. coli exhibits the following responses: 1. Lactose, glucose, mannitol, maltose, and numerous other sugars are fermented by E. coli, resulting in the formation of acid and gas. Sucrose is not fermented. Some E. coli strains are late lactose fermenters or nonlactose fermenters. 2. They do not liquefy gelatin, do not create hydrogen sulphide (H2 S),...
Lipopolysaccharide
1. E. coli’s principal cell wall antigen is heat-stable lipopolysaccharide (LPS). 2. The LPS is comprised of three parts: a genus-specific somatic O polysaccharide, a core polysaccharide shared by all Enterobacteriaceae (common antigen), and lipid A. 3. There are four primary antigens found on E. coli organisms: H or flagellar antigen, O or somatic antigen, K or capsular antigen, and F or fimbrial antigens.
H or flagellar antigen
1. On the flagella, the H antigens are heat- and alcohol-labile proteins. 2. The H antigens are typically not shared with other enterobacteria as they are genus-specific. 3. All H antigens exist as monophasic forms, but extremely rarely in diphasic forms. 4. So far, a total of 75 “H” antigens have been identified.
O or somatic antigen
1. O antigens are located on the surface of outer membranes and are determined by unique sugar sequences. 2. O antigen is an LPS complex that is a fundamental component of the cell wall. 3. It is resistant to boiling for up to two hours and thirty minutes. 4. Up to this point, 173 (1, 2, 3, etc.) O antigens have been described. 5. Somatic O polysaccharide antigen demonstrates cross-reactions with closely related taxa (Shigella, Salmonella, Yersinia, and Citrobacter) within the family Enteroba...
E. coli produces a variety of virulence factors, including the following: 1. Common factors of virulence associated with Entero bacteriaceae. 2. Particularly associated E. coli virulence factors Common virulence factors of Enterobacteriaceae include: These factors include (a) fimbriae, (b) endotoxin, (c) capsule, and (d) growth factor sequestration...
The vast majority of infections, such as UTIs and sepsis, are endogenous and are caused by E. coli that is abundant in the gastrointestinal tract of the same host. Other E. coli infections, including gastroenteritis and neonatal meningitis, are exogenous, or acquired from the outside.
Escherichia coli or E. coli can grow on ordinary media like Nutrient Agar medium (NAM).Commonly the NAM & MacConkey Agar medium is used for the cultivation of Escherichia coli in the Laboratory.The optimum temperature required for most of the E.coli strains is 37°C.E. coli can survive at 4.5– 9.5 pH but the optimum pH is 7.0.People also ask
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Jan 1, 2008 · Bacteria are the simplest living organisms. In particular, Escherichia coli has been extensively studied and it has become one of the standard model systems in microbiology. However, optical microscopy studies of single E. coli have been limited by its small size, ∼1 × 3 μm, not much larger than the optical resolution, ∼0.25 μm.
- Galina Reshes, Sharon Vanounou, Itzhak Fishov, Mario Feingold
- 10.1529/biophysj.107.104398
- 2008
- Biophys J. 2008 Jan 1; 94(1): 251-264.
Aug 31, 2023 · List and describe 5 different arrangements of cocci. Define and give the abbreviation for the metric unit of length termed micrometer and state the average size of a coccus-shaped bacterium and a rod-shaped bacterium. List and describe 2 different arrangements of bacilli. List and describe 3 different spiral forms of bacteria.
Aug 10, 2022 · The average diameter of spherical bacteria is 0.5-2.0 µm. For rod-shaped or filamentous bacteria, length is 1-10 µm and diameter is 0.25-1 .0 µm. E. coli , a bacillus of about average size is 1.1 to 1.5 µm wide by 2.0 to 6.0 µm long. Spirochaetes occasionally reach 500 µm in length and the cyanobacterium. Oscillatoria is about 7 µm in ...
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Aug 31, 2023 · Escherichia coli. Gram Stain of Escherichia coli. Note gram-negative (pink) bacilli. Escherichia coli is shared under a CC BY license and was authored, remixed, and/or curated by LibreTexts.
