Infection Genito-Urinary Tract Flashcards
Why are females more susceptible to UTI?
Vulnerable to infection with faecal bacteria - shorter urethra and closer to the anus (nature of intercourse)
What is urethritis and cystitis?
Inflammation of urethra and bladder
What is dysuria and pyuria?
Painful urination and urine that contain pus (neutrophil)
Name host factors pre-dispose UTI?
Blockage or swelling urinary tract
Men - prostate enlargement
Neurological problems - problem emptying bladder
How to diagnose UTI and what would sample show?
Midstream urine sample
- Appear cloudy
- > 10 PMNLs per high power microscope field
- > 105 cfu/ml single bacteria species
- Contain proteina and erythrocyte
Name main organisms associated UTI?
- E.coli - gram negative rod
- Proteus mirabilis - swarming gram -ve
- Staph saprophytic - gram +ve cocus
What media is used to grow bacteria?
CLED - cysteine-lactose-electrolyte-deficient media
Media contain lactose and lacking electrolyte - repress swarming
Subsequent plating MacConkey agar
What reaction do you get on CLED?
E.coli - ferment lactose - large dark yellow colonies
Proteus - translucent blue colonies
Staph.s - pale yellow colonies
Pathogenesis of E.Coli?
UPEC - type 1 pili - bind to mannose receptor on glycoprotein in uroepithelium
P-fimbrae bind gal-gal residue on ceramide host lipid
When more likely to see proteus mirabilis infection and why?
Swarming - more likely in catheters
Virulence of p. mirabilis?
Urease - convert urea –> ammonia and CO2 - cause precipitation of minerals = stones
IgA protease - reduce flushing
Which bacteria is a gram+ve cocci
Staphlyococcus saprophyticus - COAGULASE NEGATIVE
Virulence for staph. sap
Capsulated - reduce phagocytosis
Haemagglutin for attachment
Haemolysin
What is staph. s resistant to?
Novobiocin
When should and shouldn’t ab be prescribed?
Not indicated: uncomplicated lower UTI in non-pregnant women
Indicated: fever and pain in kidney area, always in men
