Neotype strain
E. coli is the type species of the genus (Escherichia) and in turn Escherichia is the type genus of the family Enterobacteriaceae, where the family name does not stem from the genus Enterobacter + "i" (sic.) + "aceae", but from "enterobacterium" + "aceae" (enterobacterium being not a genus, but an alternative trivial name to enteric bacterium).The original strain described by Escherich is believed to be lost, consequently a new type strain (neotype) was chosen as a representative: the neotype strain is U5/41T, also known under the deposit names DSM 30083, ATCC 11775, and NCTC 9001, which is pathogenic to chickens and has an O1:K1:H7 serotype. However, in most studies, either O157:H7, K-12 MG1655, or K-12 W3110 were used as a representative E. coli. The genome of the type strain has only lately been sequenced. Phylogeny of E. coli strains
Many strains belonging to this species have been isolated and characterised. In addition to serotype (vide supra), they can be classified according to their phylogeny, i.e. the inferred evolutionary history, as shown below where the species is divided into six groups. Particularly the use of whole genome sequences yields highly supported phylogenies. Based on such data, five subspecies of E. coli were distinguished.The link between phylogenetic distance ("relatedness") and pathology is small, e.g. the O157:H7 serotype strains, which form a clade ("an exclusive group")—group E below—are all enterohaemorragic strains (EHEC), but not all EHEC strains are closely related.
Muscle contractures can occur for many reasons, such as paralysis, muscular atrophy, and forms of muscular dystrophy. Fundamentally, the muscle and its tendons shorten, resulting in reduced flexibility. For example, in the case of partial paralysis (i.e. poliomyelitis) the loss of strength and muscle control tend to be greater in some muscles than in others, leading to an imbalance between the various muscle groups around specific joints. Case in point: when the muscles which dorsiflex (flex the foot upward) are less functional than the muscles which plantarflex (flex the foot downward) a contracture occurs, giving the foot a progressively downward angle and loss of flexibility. Various interventions can slow, stop, or even reverse muscle contractures, ranging from physical therapy to surgery. A common cause for having the ankle lose its flexibility in this manner is from having sheets tucked in at the foot of the bed when sleeping. The weight of the sheets keep the feet plantarflexed all night. Correcting this by not tucking the sheets in at the foot of the bed, or by sleeping with the feet hanging off the bed when in the prone position, is part of correcting this imbalance. It occurs also due to muscle tightening for example if after fracture when immobilization is done by putting plaster of paris the muscle length shortens because the muscle is not used for a large span of time.