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3 Cards in this Set
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PATHOGENESIS: process of causing disease PATHOGENICITY/VIRULENCE: pathogens ability to cause disease. Can be measured by number of organisms needed to cause disease so more virulent means less organisms. |
Primary pathogen= can cause disease in healthy individual Opportunistic= can be normal body flare which cause disease when body defences are impaired or competitors are removed eg by antibiotics Carriers carry the pathogen but don’t show symptoms |
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Virulence factors: anything that enhances the pathogens ability to inflict damage and cause disease. Could be enzymes eg Staphylococcus aureus produce coagulase which form clots, and leukocidins which destroy leukocytes Gonococcus have pilli Which enable adherence |
TOXINS: ENDOTOXINS LPS on outer membrane of gram negative cells, anchored by Lipid A which cause endotoxins shock. Symptoms - fever - vomiting - diarrhoea - inflammation Rarely fatal except in immune compromised people and can cause death Less toxic than most exotoxins |
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EXOTOXINS: diffusable polypeptides secreted by bacteria which can be fatal if eaten even if bacteria is killed. Clostridium Tetani produces tetanus toxin which acts on inhibitory neurones, preventing release of glycine so excitatory neurone stimulates muscles uncontrollably causing uncontrollable contractions |
Clostridium Botulinum produces botulinum toxin (mainly in improperly preserved foods) which blocks release of acetylcholine so muscles not contracted. Could affect breathing muscles and cause suffocation this is flaccid paralysis ENTEROTOXINS: special type of exotoxins which attack intestines. Cause massive secretion of fluid into the lumen causing vomiting and/or diarrhoea. Eg Staphylococcus aureus, vibrio cholera, E. coli, salmonella |
