Microbiology Flashcards Preview

2MB Renal > Microbiology > Flashcards

Flashcards in Microbiology Deck (45)
Loading flashcards...
1
Q

Urine in the kidneys, ureters and bladder is normally sterile. True/False?

A

True

2
Q

Which organisms usually colonise the lower end of the urethra?

A

Coliforms
Enterococci
(from large bowel)

3
Q

Define “UTI”

A

Presence of microorganisms in the urinary tract that are causing clinical infection

4
Q

Lower UTI denotes infection confined to where?

A

Bladder (cystitis)

5
Q

Upper UTI denotes infection spreading to where?

A

Ureters +/- kidneys (pyelonephritis)

6
Q

Bacteriuria (presence of bacteria in urine) always indicates a UTI. True/False?

A

False

7
Q

Why is UTI more common in women?

A

Short, wide urethra
Urethra near anus
Pregnancy

8
Q

What is the most common route of infection in UTI?

A

Ascending infection - bacteria from bowel/bladder rises upwards through ureters

9
Q

List the main causal organisms of UTI

A

E. coli
Klebsiella
Enterococci
Proteus

10
Q

Which bacteria is associated with the formation of calculi?

A

Proteus sp.

Produces urease which breaks down urea to form ammonia (increases pH), precipitating salt formation

11
Q

Which enterococcus - faecalis or faecium - is quite resistant to antibiotics?

A

Enterococcus faecium

12
Q

Which particular strain of Staphylococcus is associated with UTI?

A

Staph. saphrophyticus (coag. -ve)

Particularly in women of child-bearing age

13
Q

Which organism is associated with causing UTI in catheterised patients?

A

Pseudomonas

14
Q

Which antibiotic is Pseudomonas not resistant to?

A

Ciprofloxacin

15
Q

List the main symptoms and signs of UTI

A

Dysuria
Frequency/nocturia
Haematuria

16
Q

What clinical features suggest an upper UTI?

A

Fever
Loin pain
Rigors

17
Q

When taking a urine sample to check for UTI, the first urine passed is assessed. True/False?

A

False

First urine is likely to be contaminated; collect mid-stream sample

18
Q

List different ways of collecting urine specimens

A
Midstream bowl by patient
Clean catch by nurse
Bag urine (babies)
Catheter specimen
Suprapubic aspiration
19
Q

Which container contains preservative that can prevent bacteria multiplying in a urine sample?

A

Boricon (red top) container

Works for 24hrs

20
Q

If a urine sample is collected in a standard universal (white top) container, how quickly must it reach the lab?

A

Within 2 hours of collection

21
Q

The presence of nitrites on dipstick suggests what?

A

Bacteriuria

bacteria reduce nitrate to nitrite

22
Q

Which organism does not give a positive nitrite test on dipstick?

A

Enterococcus spp.

23
Q

What is looked for on urine microscopy?

A

Pus cells +/- red cells

24
Q

Define Kass’s criteria for diagnosing UTI in women of child-bearing age

A

Less than 10^4 organisms/ml - unlikely UTI

10^4 organisms/ml - possible (repeat)

More than 10^5 organisms/ml - probable UTI

25
Q

ESBL-producing bacteria are resistant to which antibiotics?

A

Cephalosporins

Penicillins

26
Q

Which antibiotics may be useful for ESBL-producing bacteria?

A
Nitrofurantoin
Pivmecillinam
Fosfomycin
Temocillin
Meropenem
Ertapenem
27
Q

Carbapenemase-producing enterobacteriaceae (CPE) are resistant to which antibiotics?

A

All current antibiotics!

28
Q

Some antibiotics are metabolised and excreted by the liver. What is the significance of this?

A

Not useful for treating UTI

29
Q

How is uncomplicated lower UTI in women treated usually?

A

3 day course of empirical antibiotic

30
Q

List 1st line antibiotics for UTI

A

Amoxicillin
Trimethoprim
Nitrofurantoin
Gentamicin

31
Q

List 2nd line antibiotics for resistant UTI

A
Pivmecillinam
Temocillin
Cefalexxin
Co-amoxiclav
Ciprofloxacin
32
Q

Enterococcus faecalis is sensitive to amoxicillin. True/False?

A

True

33
Q

Amoxicillin is good for empirical UTI treatment. True/False?

A

False

Resistant rate too high - only used if know organism is sensitive

34
Q

Which antibiotic is usually used for empirical UTI treatment?

A

Trimethoprim

35
Q

How does trimethoprim work? What is the significance of this?

A

Inhibits folic acid synthesis - thus not recommended in early pregnancy

36
Q

Trimethoprim can be given as co-trimoxazole. What is a risk of this drug?

A

Causes Stevens-Johnson syndrome

37
Q

Nitrofurantoin is only useful in uncomplicated lower UTI. True/False?

A

True

38
Q

Should nitrofurantoin be avoided in pregnancy?

A

Yes

Can cause neonatal haemolysis

39
Q

By definition, hospitalised UTI is usually treated by gentamicin. True/False?

A

True

Except in pregnancy; can cause ototoxicity

40
Q

What is the maximum duration of prescription of gentamicin?

A

3 days

41
Q

Which antibiotics have some activity against ESBL-strains?

A

Pivmecillinam

Temocillin

42
Q

State empirical antibiotic treatment for female lower UTI

A

Trimethoprim/nitrofurantoin

43
Q

State empirical antibiotic treatment for uncatheterised male UTI

A

Trimethoprim/nitrofurantoin

44
Q

State empirical antibiotic treatment for complicated UTI/pyelonephritis in GP

A

Co-amoxiclav/co-trimoxazole

45
Q

State empirical antibiotic treatment for complicated UTI/pyelonephritis in hospital

A

Amoxicillin + gentamicin

co-trimoxazole if pen-allergic