Define an urinary tract infection (UTI).
The inflammatory response of the urothelium to bacterial invasion, usually associated with bacteriuria (bacteria in urine) and pyuria (pus in urine).
What is numerically defined as an UTI?
Defined as >105 organisms/ml or fresh mid-stream urine
What are the 5 main pathogens account for nearly ALL ISOLATE from primary care?
KEEPS:
* K = Klebsiella spp.
* E = E.coli - MOST COMMON
* E = Enterococci
* P = Proteus spp.
* S = Staphylococcus spp. - coagulase negative
Name 3 UTI causative organisms.
Give 5 risk factors for UTIs.
What are the 3 different classifications of UTIs?
Uncomplicated vs complicated UTI?
Uncomplicated - healthy non pregnant women
Everyone else - complicated
How to treat uncomplicated UTIs in young women?
3 days abx
E.G. nitrofurantoin or trimethoprim
What is the first line treatment for an uncomplicated UTI?
How does trimethoprim work?
It affects folic acid metabolism.
How to manage ‘complicated’ UTI?
MSU for culture
7 days abx
Describe the management for a complicated UTI.
Same as for an uncomplicated UTI but a MCS MSU is essential! The patient would normally take a longer Abx course tailored to sensitivity.
3 things about UTI in pregnancy?
What determines if a UTI is complicated or uncomplicated?
A UTI is deemed complicated if it affects:
Give 3 bacterial virulence factors that aid their ability to cause UTI’s.
Under what circumstances would you see higher rates of adhesion?
Why?
Oestrogen depletion due to the loss of lactobacilli and pH change:
Give 5 host defence mechanisms against urinary tract infection.
Give 3 methods of avoiding host defences.
Give an example of enzyme production as a method of avoiding host defences.
E.coli release cytokine that are directly toxic
Give an example of toxin production as a method of avoiding host defences.
Proteus spp. secrete urease:
* Increases risk of stone formation
Give an example of a gram negative bacteria that releases urease.
Gram-negative: Proteus, Klebsiella & Pseudomonas
Give an example of a gram positive bacteria that releases urease.
Gram-positive: Staphylococci & Mycoplasma
Give 2 reasons why a post menopausal woman is more susceptible to a UTI.
The vagina is heavily colonised with lactobacilli. What is the function of this?
Helps maintain a low pH = host defence mechanism.