4.2: Microbiology of UTI Flashcards
True or False:
Urine in the kidneys, ureter and bladder is usually sterile?
Lower urethra is also sterile?
TRUE: Urine in the kidneys, ureter and bladder is usually sterile
FALSE: Bacteria colonise the lower urethra
Describe the colonisation of the lower urethra?
Colonised by normal bowel flora
Eg: Coliforms and Enterococci
Define a UTI?
The presence of micro-organisms in the urinary tract that are causing clinical infection
Describe a lower UTI?
Describe an upper UTI?
LOWER UTI = Infection confined to the bladder (Eg: Cystitis)
Upper UTI = Infection involving the ureters and also kidneys (Eg: Pyleonephritis)
Describe a complicated UTI?
This is a UTI complicated by something else, EG:
- systemic sepsis,
- urinary structure abnormality
- stones
Describe bacteriuria?
Describe the clinical significance of this?
Presence of bacteria in the urine
Doesn’t always mean infection, especially in elderly with catheters
Can have chronic bacteriuria - DOESN’T NEED ANTIBIOTICS AS THEY HAVE NO SYMPTOMS
What is cystitis?
What causes it?
Inflammation of the bladder
Can be caused by infections BUT there are other causes
Are UTIs common or rare?
Who are they seen in? (Name 3 groups)
Very common
- More common in women due to shorter urethra
- Those with catheters
- Patients with abnormalities of the urinary tract
True or False:
Women often get UTIs during pregnancy?
True
Describe the two routes of UTI infection?
Which is the commonest?
Ascending infection* MOST COMMON
(Bacteria from bowel, enters urethra, enters bladder, enters ureter, enters kidneys)
Infection from blood
(Bacteriaemia causes bacteria in blood, infection enters kidney, multiple small abscesses, bacteria in urine)
Describe the causative organisms of UTI?
Describe their gram film appearance?
Coliforms (Eg: E.coli, Klebsiella, Enterobacter, Proteus)
Found in the bowel
GRAM NEGATIVE BACILLI
Most common causative organism for UTI?
E.Coli
Describe proteus UTI?
Associated with renal stone formation
Causes particularly smelly urine
Produces urease which breaks down urea to ammonia - increases pH and increases stones
What are the two types of Enterococci UTI?
How sensitive are they to treatment?
Enterococcus Faecalis (Sensitive to antibiotics)
Enterococcus Faecalum (Harder to treat)
Describe Staph UTI?
Staphylococcus Saphrohyticus
Causes UTI in young women of child bearing age
Staph aureus can also cause UTI but less common
Give the full name of the Pseudomonas that causes UTI
What kind of organism is this?
When is this seen?
Treatment?
Pseudomonas Aeruginosa
Gram negative bacilli but not a coliform
Very common in catheters/instrumentation
Hard to treat
Only treatment is Ciprofloxacin
Ciprofloxacin has a negative side effect - what is this?
What UTI organism can only be treated by Ciprofloxacin?
Causes c.diff
Pseudomonas Aeruginosa
Symptoms and signs of UTI?
Dysuria
Frequency
Nocturia
Haematuria
Fever*
Loin Pain*
Rigors*
*suggests upper UTI*