Defence mechanisms of the urinary syste1

Defence mechanisms of the urinary syste1 - Defence...

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Defence mechanisms of the urinary system This note covers the defence mechanisms of the urinary system UTIs and defence Pathogenesis Between voiding, organisms may ascend urethra ---- Commoner in females as urethra shorter Commonest pathogens: Gram –ve rods, esp. Enterobacteriae ---- Coliforms, esp. E. coli Coagulase –ve Staphylococci cause infections in young women ---- Staph. Saprophyticus Hospitalised patients: Wide range of pathogens as result of greater antibiotic selective pressure o Coagulase –ve Staph o Coliforms, esp. E. coli o Other Gram –ves, e.g. Pseudomonas aeruginosa Host factors: Shorter urethra means more infections in females Obstruction can be caused by enlarged prostate, pregnancy, stones, tumours Neurological problems can be incomplete emptying and therefore residual urine Ureteric reflux can lead to ascending infections from the bladder, especially in children. Bacterial factors: Faecal flora means potential urinary pathogens colonise periurethral area Adhesion - Fimbriae and adhesions allow attachment to urethral and bladder epithelium K antigens allow some E. coli to resist host defences by producing polysaccharide capsule Haemolysins can damage the membranes and cause renal damage
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This note was uploaded on 12/04/2011 for the course ANTHRO 2000 taught by Professor Monicaoyola during the Fall '10 term at Broward College.

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Defence mechanisms of the urinary syste1 - Defence...

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