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    Ok this question is for Option A Edexcel biologists (Microbiology):

    Is the reason why the onset of the symptoms of Staphylococcus aureus takes a shorter time than Salmonella enteriditis because Staphylococcus releases exotoxins, whereas Salmonella releases endotoxins?

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    i don't have to know about that specifically, but i would assume so- extoxins are released right after the pathogens produce them- endotoxins are only released when the pathogens die so the onset of the symptoms would naturally take longer.

    maybe the salmonella has a slightly different method of invasion and entry as well? which could take longer? ( dunno i'm making things up here, but hey its plausible )
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    (Original post by Silly Sally)
    Ok this question is for Option A Edexcel biologists (Microbiology):

    Is the reason why the onset of the symptoms of Staphylococcus aureus takes a shorter time than Salmonella enteriditis because Staphylococcus releases exotoxins, whereas Salmonella releases endotoxins?

    Thanks

    you should know this silly:P its on tuesday! <gasps>
    yes that is the reasons, but there is more reasoning behind that.

    staphylococcus releases their toxins (entertoxins) out of their cell so no suprises why in small concentrations this would set off an immune response hence that is also why symptoms show very quickly.

    with salmonella they produce the toxins inside (endotoxins) and salmonella are taken up my phagocytes - they keep producing these toxins, and it is not until the phagocytes eat them up do they release these toxins - and they have to be in large amount to cause an effect - thats why food poisoning from poultry only shows after 1-2 days after ingestion. you get the fever with this one too because there's so much toxin around its mad.


    does this help ?
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    staphylococcus releases their toxins (entertoxins)
    Actaully, staphylococcus released exotoxins. Endotoxins and exotoxins are types of enterotoxins.
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    (Original post by ianaf18)
    Actaully, staphylococcus released exotoxins. Endotoxins and exotoxins are types of enterotoxins.
    Yup....i.e. they act on the gut....Salmonella causes inflammation of the tissue immediate to the site of infection and fever...whereas the staph exotoxins in small concentrations cause vomiting + diarrhoea.

    G
 
 
 
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