Shiga toxin: Difference between revisions
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<StructureSection load='2xsc' size='450' side='right' scene='' caption=''> | <StructureSection load='2xsc' size='450' side='right' scene='' caption='E. coli Shiga toxin subunit B complex with Zn+2 (grey (PDB code [[2xsc]])'> | ||
==Introduction== | ==Introduction== | ||
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0157:H7 STECs are spread to humans through a fecal-oral mechanism, primarily from ingestion of food contaminated with fecal material. Cattle, goats, and sheep are the primary reservoir of STECs and their close proximity to food sources as well as the use of animal feces for fertilizer makes them the main route of contamination.<ref name=Herold>PMID: 15493821</ref> These animals can house STEC's without effect due to a lack of Stx surface receptors.<ref name=Asakura>PMID: 11561972</ref> Inadequate sanitation and contamination of meat during slaughter can both lead to STEC contaminated food at the market. Once ingested the STEC can survive the high acid environment of the stomach and progress to the gut where they attach firmly to gut mucosa via the [http://en.wikipedia.org/wiki/Intimin intimin adhesin protein].<ref name=Russel>PMID: 11321582</ref> Secreted Stx then either attacks gut epithelia or passes into the bloodstream where it can damage kidney and brain tissue. | 0157:H7 STECs are spread to humans through a fecal-oral mechanism, primarily from ingestion of food contaminated with fecal material. Cattle, goats, and sheep are the primary reservoir of STECs and their close proximity to food sources as well as the use of animal feces for fertilizer makes them the main route of contamination.<ref name=Herold>PMID: 15493821</ref> These animals can house STEC's without effect due to a lack of Stx surface receptors.<ref name=Asakura>PMID: 11561972</ref> Inadequate sanitation and contamination of meat during slaughter can both lead to STEC contaminated food at the market. Once ingested the STEC can survive the high acid environment of the stomach and progress to the gut where they attach firmly to gut mucosa via the [http://en.wikipedia.org/wiki/Intimin intimin adhesin protein].<ref name=Russel>PMID: 11321582</ref> Secreted Stx then either attacks gut epithelia or passes into the bloodstream where it can damage kidney and brain tissue. | ||
==Treatments== | |||
Treatment with antibiotics is contraindicated as antibiotic treatment has been demonstrated to increase Stx production up to one hundred fold.<ref name=Herold>PMID: 15493821</ref> This results from the link between Stx production (and phage induction) to the [http://en.wikipedia.org/wiki/SOS_response SOS response pathway].<ref name=Herold>PMID: 15493821</ref> In the event of renal failure kidney dialysis may be employed. A number of potential treatments are under development including B subunit inhibitors, polysaccharides that promote macrophage uptake of Stx, blocking of the Gb<sub>3</sub> membrane receptor, and inhibition of [http://en.wikipedia.org/wiki/Retrograde_transport#Retrograde_transport retrograde transport].<ref name=Nishikiwa>PMID: 21644029</ref> | Treatment with antibiotics is contraindicated as antibiotic treatment has been demonstrated to increase Stx production up to one hundred fold.<ref name=Herold>PMID: 15493821</ref> This results from the link between Stx production (and phage induction) to the [http://en.wikipedia.org/wiki/SOS_response SOS response pathway].<ref name=Herold>PMID: 15493821</ref> In the event of renal failure kidney dialysis may be employed. A number of potential treatments are under development including B subunit inhibitors, polysaccharides that promote macrophage uptake of Stx, blocking of the Gb<sub>3</sub> membrane receptor, and inhibition of [http://en.wikipedia.org/wiki/Retrograde_transport#Retrograde_transport retrograde transport].<ref name=Nishikiwa>PMID: 21644029</ref> | ||