currently available. The only remaining blockades to the use of PCR as a standard tool of diagnosis are in its cost and application, neither of which is insurmountable. The diagnosis of a few diseases will not benefit from the development of PCR methods, such as some of the clostridial diseases (tetanus and botulism). These diseases are fundamentally biological poisonings by relatively small numbers of infectious bacteria that produce extremely potent neurotoxins. A significant proliferation of the infectious agent does not occur, this limits the ability of PCR to detect the presence of any bacteria. 5.Millest tulevad vead immunoloogiliste meetodite kasutamisel nakkushaiguste diagnoosimisel? Milliseid vigu ja kuidas saab vältida? 6.Mis on meetodi tundlikkus? 3 Sensitivity A sensitivity of 100% means that the test recognizes all actual positives - for example, all
heat sensitive (except the staphylococcal Clostridium perfringens enterotoxins described earlier). These toxins also have a distinct pharmacology. Clostridium perfringens occupies an interest- Examples of exotoxins are staphylococcal ing position, since it is both a food-borne enterotoxins (affecting the intestinal tracts) infection agent as well as a food-borne intox- and botulinum neurotoxins (affecting the ication agent. On the one hand, the suscep- nervous system). tible person has to ingest large numbers of Endotoxins are part of the cell wall mate- viable C. perfringens before coming down rial of Gram-negative cells. Every Gram- with a food-poisoning case, and on the other negative bacterium examined has endotoxins. hand, the organism produces an enterotoxin
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