Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Micro > Microbiology 6: Urinary Tract Infections > Flashcards

Microbiology 6: Urinary Tract Infections Flashcards

1
Q

What is the most common causative organism for UTI’s ?

A

E.coli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Name a virulence factor of some E.Coli serotypes that make them well adapted to cause UTIs ?

A

P-fimbriae

These allow the bacteria to adhere to the epithelium and therefore ascend

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which commensal skin bacteria is a rare cause of UTI but is more common in patients with Prosthesis e.g they have a long term in dwelling catheter ?

A

Staphylococcus epidermidis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which 4 organisms are more common causes of UTIs in people with structural abnormalities ?

A
  • Proteus mirabilis (kidney stones)
  • Pseudomonas
  • Klebsiella aerogenes (occur in abnormal urinary tracts - stones, neuro + anatomical abnormalities)
  • Enterococcus faecalis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

List 4 neurological causes of obstruction in the urinary tract ?

A

Poliomyelitis
Tabes dorsalis
Diabetic neuropathy
Spinal cord injury

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which organisms can cause a UTI which is negative for nitrites but positive for leucocytes on urine dipstick ?

A
  • (Non coliform bacteria)
  • Staphylococcus saphrophyticus
  • Enterococcus faecalis
  • Could also be urethral syndrome
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

List 3 ways you could collect a urine sample ?

A

Mid stream urine (MSU) - PREFERRED
Catheterisation
Supra Pubic aspiration

NB do the last 2 in certain situations to try and get a clean sample e.g. in young children

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the most common causes of Sterile pyuria? (raised WCC but no growth on culture)

Other causes (5)

A

Prior treatment with antibiotics

Others:

  • calculi: inflammation but not infection
  • catheterisation
  • bladder neoplasm
  • TB - rare
  • STD (chlamydia)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What colour is E.coli on chromogenic agar ?

A

Pink

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the most common treatment for an uncomplicated UTI ?

A

Empirical treatment - Nitrofurantoin/Trimethoprim (3 days)

Although the resistance of E.coli is rapidly increasing so check with local governance.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which infections occur in patients that have indwelling catheters ?

A

Candida

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the most common treatment for Pyelonephritis ?

A

Co-amoxiclav +- gentamicin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Which organism that is not E.Coli tends to cause UTIs particularly in young women (2nd most common cause of UTI)?

A

Staphylococcus Saphrophyticus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Name a congenital abnormality that causes oligohydramnios and can cause Potter’s syndrome in male neonates?

A

Posterior urethral valve (PUV)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Give an example of a paediatric cause of Kidney scarring ?

A

Vesicoureteric reflux (VUR)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

define uncomplicated UTI

A

infection is in a structurally and neurologically normal urinary tract - usually refers to lower UTI in women

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

define complicated UTI

A

infection in a urinary tract with functional or structural abnormalities (including indwelling catheters and calculi)

  • men: greater urethral length so considered complicated (basically harder for them to get infected, so if they are, then more likely complicated reason)
  • pregnant
  • children: valves
18
Q

what is staphylococcus saprophyticus

A
  • coagulase negative
  • 2nd commonest cause of UTI in young women (after Escherichia coli)
  • P fimbrae allows adherence to the epithelium
19
Q

how can reflux cause UTIs

A
  • vesicoureteric reflux
  • residual pool of urine in the bladder after urination that can go back up to kidneys rather than leaving the body
  • can cause kidney scarring
20
Q

symptoms of UTI in nonates and children <2 yrs

A
  • non specific
  • failure to thrive
  • vomiting
  • fever
21
Q

symptoms of UTI in children >2

A
  • frequency
  • dysuria
  • abdominal or flank pain
22
Q

what do the following of urine culture suggest:

  • white cells pyuria
  • squamous epithelial cells
A
  • white cells pyuria - infection
  • squamous epithelilal cells - contaminations
23
Q

Mx of fungal urinary tract infection

Why is it difficult to treat?

A
  • PO Fluconazole is the treatment of choice BUT there is increased resistance
  • If fluconazole is NOT effective, use non-liposomal amphotericin B

Difficult to treat since Lots of antifungals used do not get excreted in the urine

24
Q

how many single organisms must be cultures to diagnose UTI

A

>10^5 CFU/mL with urinary symptoms

25
Q

different colours on chromogenic agar

A

pink = E.Coli (gram -ve)
blue = other coliforms
light blue/purple = gram positives

26
Q

which antibiotics are used to treat UTI

A
  • nitrofurantoin - EGFR must be >45ml/min
  • trimethoprim - if low risk of resistance (50% of E coli is resistant)
  • pregnant/ breastfeeding = cefalexin, co-amoxiclav (2nd line)
  • male = cefalexin, ciprofloxacin
  • pyelonephritis = co-amoxiclav +- gentamicin
27
Q

You do urine sample. Lots of squamous cells. What does this mean?

A
  • squamous cells = urethra
  • implies that the sample is NOT a midstream urine and it represents colonisation from the urethra
  • A true MSU will show what is going on in the bladder
28
Q

product of nitrate reductase found on dipstick

A

nitrite

29
Q

Which part of kidney is usually infected in Pyelonephritis and why?

A
  • Renal medulla - Very few organisms are needed to infect
  • Many more organisms are needed to infect the cortex
30
Q

Nitrites vs leukcoytes meaning on dipstick

What does nitrite -ve and leuckoyte +ve mean?

A
  • Nitrites are very specific because they are produced by E. coli
  • Leukocyte esterase is produced by the leukocytes- this is a marker of inflammation
  • Means may be a UTI caused by a non-coliform bacterium (coliform bacteria are what convert nitrate to nitrite)
31
Q

Which group is ASx bacteria more common in?

A

Elderly - Just because there may be bacteria in urine does NOT mean they have a UTI (don’t need to treat)

32
Q

Complicated vs uncompicated UTI

A
  • uncomplicated: ction in a structurally and neurologically NORMAL urinary tract
  • complicated: infection in a urinary tract with functional or structural ABNORMALITIES (including indwelling catheters, stents, calculi, congenital abnormalities)
33
Q

Organism associated with kidney stones

A

Proteus mirabilis

34
Q

Organism associated with kidney stones

A
35
Q

The kidney is frequently the site of abscesses in patients with what infection (2)

What route does it get to the kidney

A

Staphylococcus aureus bacteraemia or endocarditis, or both

Via blood

36
Q

Sterile pyuria is due to what?

A

ABx use

37
Q

How to culture for UTI Ix

A

on chromogenic agar

38
Q

What is now the preferred ABx for uncomplicated UTI and why?

A

Nitrofurantoin (over trimotheprim) since there is less resistance

39
Q

R of using nitrofurantoin in 3rd trimester

A

neonatal haemolysis

40
Q

Mx of Catheter-associated UTI

A

STAT doses of aminoglycoside (gentamicin)

Micro (20 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions