Microbiology and Immunology 2500A/B Lecture Notes - Lecture 13: Staphylococcus Saprophyticus, Virulence Factor, Staphylococcus Epidermidis
18 Nov 2016
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Document Summary
In the united states: causes > 10 million skin and soft tissues infections/yr in u. s, ~80 000 invasive infections. Immune evasion mechanisms: resistance to antibody mediated phagocytosis. Immune evasion mechanisms: exotoxins that kill leukocytes. S. aureus can make a number of cytolytic toxins that kill white blood cells. Often called hemolysins because they can lyse red blood cells. Actual targets are mostly white blood cells. Helps to protect s. aureus in abscesses and for spreading. Hemolysins: because when they grow on a blood plate they kill the red blood cells: released at the beginning before s. aureus is attached by wbc so not destroyed, the actual target is probably actually wbc though. Disease due to direct effect of organism: skin lesions, deep abscesses, systemic infections. Skin lesions: impetigo superficial skin infection usually in young children, non bullous form has pimple-like lesions with pus. Also caused by streptococcus pyogenes: the bullous form has painless, fluid filled blisters.
