Wednesday, 22 January 2014

Endotoxins

Staphylococcus- binds fcIg by protein A, inhibits complement fixation n phagocytosis
Corynebacterium-ADP ribosylation of EF-2
Clost.tetani-blocks glycine &GABA release 4m renshaw cells in spinal cord
C.botulinum-inhibits ach release at NM Jn-FLOPPY BABY SYNDROME
Both tetani n botulinum toxin cleaves SNARE protein required 4 neurotransmitter release
C.difficile-toxin A- enterotoxin n brush border of gut
Toxin-B- cytotoxin destroys enterocytes causing pseudomemb colitis
B.anthracis-lethal &edema factors, edema factor resembles adenylate cyclase(inc cAMP), Capsular polysacc inhibits phagocytosis
B.cereus-enterotoxin similar to e.coli toxin, emetic type resembles staph enterotoxin.causes REHEATED RICE SYNDROME
Listeria- actin rockets move 4m cell to cell
P.aeruginosa-exotoxin A inactivates EF-2
M.tb- neutrophil migration factor inhibitor, virulent strains inhibit macrophage maturation n phagolysosomal fusion
Shigella- inactivates 60S ribosomes by removing adenine 4m rRNA n evades host cells
EHEC-shigella like toxin- does not evade host cells, enhances cytokine release
ETEC- Heat labile- inc cAMP &Inc chloride secretion n gut-water efflux
Heat stable- Inc cGMP& Dec reabsorption of Nacl and water in gut
V.cholera-Inc cAMP, Inc chloride sec in gut&water efflux
Bordetella-inc cAMP disables Gi n impairs phagocytosis
C.perfringens-phospholipase c causing myonecrosis by alpha toxin
S.pyogenes- strep O degrades cell memb n lyses RBCs, M proteins inhibit phagocytosis
H.influenza,S.pneumoniae,Neisseriae- IgA protease cleaves IgA

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