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Bacterial taxonomy is the classification of strains within the domain Bacteria into hierarchies of similarity. This classification is similar to that of plants , mammals , and other taxonomies. However, biologists specializing in different areas have developed differing taxonomic conventions over time.
Escherichia coli is one of the most diverse bacterial species, with several pathogenic strains with different symptoms and with only 20% of the genome common to all strains. [1] Furthermore, from the evolutionary point of view, the members of genus Shigella ( dysenteriae , flexneri , boydii , sonnei ) are actually E. coli strains "in disguise ...
There is a single type strain for each prokaryotic species, but different culture collections may designate a unique name for the same strain. For example, the type strain of E. coli (originally strain U5/41) is called ATCC 11775 by the American Type Culture Collection, DSM 30083 by the German Collection of Microorganisms and Cell Cultures, JCM ...
E. coli and related bacteria constitute about 0.1% of gut flora, [4] and fecal–oral transmission is the major route through which pathogenic strains of the bacterium cause disease. Cells are able to survive outside the body for only a limited amount of time, which makes them ideal indicator organisms to test environmental samples for fecal ...
For example, a "flu strain" is a certain biological form of the influenza or "flu" virus. These flu strains are characterized by their differing isoforms of surface proteins. New viral strains can be created due to mutation or swapping of genetic components when two or more viruses infect the same cell in nature. [3]
For example, when carbohydrates are fermented, the pH within the well decreases and that is indicated by a change in the color of the pH indicator. All test results are compiled to obtain a profile number, which is then compared with profile numbers in a commercial codebook (or online) to determine the identification of the bacterial species.
Bacterial morphological plasticity refers to changes in the shape and size that bacterial cells undergo when they encounter stressful environments. Although bacteria have evolved complex molecular strategies to maintain their shape, many are able to alter their shape as a survival strategy in response to protist predators, antibiotics, the immune response, and other threats.
The relative risk (RR) or risk ratio is the ratio of the probability of an outcome in an exposed group to the probability of an outcome in an unexposed group. Together with risk difference and odds ratio , relative risk measures the association between the exposure and the outcome.