Microbiology of UTI's Flashcards
What is the definition of a UTI? what is the difference between a lower and upper UTI?
presence of microorg.s in tract causing an environmental infection
Lower - confined to bladder
Upper - involves ureters +/- kidneys
what is the definition of a complicated UTI?
UTI + systemic sepsis or urinary structural abnormality or stones
what is:
- bacteruria
- cystitis?
Bacteruria - bacteria in urine (not always a UTI)
cystitis - inflammation of bladder
what is the colonisation of the normal urinary tract?
Kidneys/ureter/bladder - sterile
Lower urethra - coliforms/enterococcus
Why are women more susceptable to UTI’s? what increases the risk of UTI’s?
Short (5cms) wide urethra that’s in close proximity to the anus
Increased risk if: pregnant, sexual intercourse, catheter, abnormal urinary tract
What are the two different routes of UTI?
Ascending or from bloodstream due to bacteraemia/septicaemia
what are the 4 different coliforms assoc. with UTI’s?
coliforms = gram -ve bacilli
-e.coli
-klebsiella
-enterobacter sp
-proteus sp
other coliforms
What is a UTI due to proteus assoc. with?
stone formation: produces urease that breaks down urea = ammonia = increases the urinary pH = precipates salt
What gram -ve bacilli that is not considered a coliform can cause UTI’s? What are UTI’s due to this organism assoc. with?
pseudomonas aeruginosa
- assoc. with catheters and other instrumentation
- resistant to most abiotic except ciprofloxacin
What gram positive organisms cause UTIs?
- Enterococcus
- staphylococcus saphrophyticus
- staph aureus
Enterococcus:
- what type of organism is this?
Gram positive streptococci that occur as diplococci or in strips
-gamma haemolytic (do not cause haemolysis)
Staphylococcus saphrophyticus
- What type of organism is this?
- what demographic of patients does this affect?
coagulase negative staphylococcus
-affects women of child bearing age
What are the 7 s/s of UTI?
Dysuria frequency nocturia haematuria fever loin pain rigors
what type of urine sample is important when testing for UTI’s in general?
MSSU
When would: -clean catch urine -bag urine -catheter specimen -suprapubic aspiration be used to collect a urine sample?
Clean catch: babies/elderly
Bag urine: attach a bag to urethral meatus in babies - often contaminated with bowel flora so if positive have to do a suprapubic aspiration to confirm
catheter specimen - aspirate from tube
suprapubic aspiration - babies/young children