Urinary tract infections Flashcards
What differentiates upper urinary tract from lower urinary tract?
Above bladder = upper urinary tract
What flora is found within the urinary tract (kidneys/ureter, bladder and urethra)?
Kidneys/ureters = sterile Bladder = usually considered sterile but may not be the case Urethra = Perineal flora (skin/lower GI tract flora)
What is the predominant skin flora making up the perineal flora?
Coagulase negative staphylococci
What lower GI tract flora can make up part of the perineal flora? 3
1) Anaerobic bacteria
2) Aerobic bacteria - enterbacertiacae
3) Gram-positive cocci - enterococcus spp.
What is cystitis?
Lower urinary tract infection
What 5 components make up the syndrome of cystitis?
1) Dysuria
2) Urinary frequency
3) Urgency
4) Supra-pubic tenderness/ pain
5) Polyuria, nocturia, haematuria
What is pyelonephritis?
Upper urinary tract infection - infection of kidney and or renal pelvis
What are the 3 main symptoms of pyelonephritis?
1) Loin/abdominal pain/ tenderness
2) Fever
3) Other evidence of systemic infection eg. rigors, nausea, fever, diarrhoea, elevated CRP and WBC
What is urethral syndrome?
Also called abacterial cystitis or frequency-dysuria syndrome - symptoms of lower UTI without demonstratable infection
Which group does urethral syndrome commonly affect?
Women - 30-50 years of age
How is significant bacteriuria classified, what does that indicate?
10^5 cfu/ml (colony forming units)
Indicated likely UTI
What levels of bacteria indicate probable UTI?
10^4-10^5 cfu/ml
What are the 4 main limitations of defining significant bacteriuria and using this as an indicator of UTI?
1) Bacterial count is on a normal curve
2) Many symptomatic females have bacterial counts less than that considered significant bacteriuria
3) Lower counts 10^3cfu/ml are considered significant in males
4) Not relevant to catheter urine or sterile-aspirate urine
What is asymptomatic bacteriuria?
Significant bacteriuria with a single organism
With no symptoms of urinary tract infection
What is sterile pyruria?
Pus cells in urine
No organisms grown
Give 6 predisposing factors for UTI?
1) Female sex - 10:1
2) Urinary stasis (pregnancy, prostatic hypertrophy, stones, strictures, neoplasia, residual urine)
3) Instrumentation - eg. cystoscopy
4) Sexual intercourse
5) Fistuale - recto-vesical, vesico-vaginal
6) Congenital abnormalities - vesico-ureteric reflex
Give 3 sources of infection in UTI?
1) Perineum - movement of bacteria along a lumen
2) Fistulae - Movement of bacteria from genital/GI tract to urinary tract
3) Haematogenous (rare) - seeding of infection from the blood
What is the most common bacteria to cause UTI both in general practise and in hospital?
E coli
What is the second most common bacterial cause of UTI in general practise?
Staphylococcus saprophyticus
What is the second most common bacterial cause of UTI in hospitals?
Enterococcus spp.
What are the 3 causes of sterile pyuria?
1) Inhibition of bacterial growth - unprescribed abx, specimen contaminated with antiseptic
2) Fastidious (hard to grow) organisms - eg. mycobacterium TB, haemophilus spp., Neisseria gonorrhoeae and anaerobes
3) Urinary tract inflammation - renal or bladder stones, other renal disease
What is a catheter UTI?
Long-term indwelling catheterization results in bacteriuria
What 2 things is it important to distinguish between in catheter UTI, how are the distinguished?
Need to distinguish between colonisation and infection
Do so through looking at clinical features
How many catheter UTI lead to bacteraemia, how can this be avoided?
Manipulation or catheter removal may result in bacteraemia - prophylactic Abx may be used to prevent this in people with a hx of this problem, purulent discharge at site or colonisation of catheter exit site with staph aureus
