3: Microbiology of UTI Flashcards Preview

Renal Week 4 2017/18 > 3: Microbiology of UTI > Flashcards

Flashcards in 3: Microbiology of UTI Deck (66):
1

What is a UTI?

Microorganisms in the urinary tract which are causing INFECTIOUS SYMPTOMS

2

What is a lower UTI?

Confined to the bladder (cystitis)

3

What is an upper UTI?

Infection involving the ureters AND/OR kidneys

(pyelonephritis)

4

Urine is normally ___.

sterile

5

What is a complicated UTI?

Symptoms of UTI (e.g dysuria, urgency, increased frequency) with any of:

SYSTEMIC SYMPTOMS (fever, rigors, N&V...)

RENAL STONES

ANATOMICAL ABNORMALITIES

6

Does bacteruria mean infection?

Not without symptoms

7

What is a common site for colonisers of the urinary tract?

Catheter

8

(Men / women) are more likely to develop UTIs.

women

shorter, wider urethras

sex

pregnancy

9

People with ___ are more likely to get UTIs.

catheters

10

What are the two routes of infection in UTI?

Ascending route

Haematogenous

11

What is the most common organism causing UTIs?

E. coli

12

Why is E. coli well adapted to causing UTIs?

Common bowel commensal

Have fimbriae (sticky appendages which let them climb all over the place)

13

Which investigations are used to

a) rule out

b) properly diagnose

UTIs?

a) Dipstick

b) Urine culture

14

What is the best investigation for UTI?

Urine culture

15

What are coliforms?

Gram negative bacilli

most commonly E. coli

16

E. coli is also called a ___ fermenter.

lactose fermenter

along with Klebsiella, Enterobacter

17

What organisms commonly cause UTIs?

Escherichia

Klebsiella

Enterobacter

Proteus

Pseudomonas

18

What does E coli produce to cause sepsis?

Endotoxin

19

What renal disease is Proteus associated with?

Renal stones

particularly struvite stones

20

Which UTI organism is associated with renal stones?

Proteus

21

Which type of renal stone is commonly seen in Proteus infection?

Staghorn calculus

22

Is Pseudomonas a coliform?

NO

but it is a Gram -ve bacillus

23

What is Pseudomonas UTI associated with?

Catheters

Surgery

24

How is Pseudomonas UTI treated?

Ciprofloxacin

25

How does ciprofloxacin work?

Affects bacterial DNA

26

What are the 4Cs?

Co-amoxiclav

Ciprofloxacin

Clindamycin

Cephalosporins

27

What's the difference between Enterobacter and Enterococcus?

Enterobacter is a Gram -ve bacillus

Enterococcus are Gram +ve

28

What is a Gram positive coccus which causes UTI?

Enterococcus (faecalis)

Staph. saphrophyticus

29

What is a type of Staphylococcus associated with UTIs in women of child bearing age?

Staph. saphrophyticus

30

What are the symptoms of UTI?

Dysuria

Haematuria (not always)

Nocturia

Increased frequency

Constitutional symptoms

31

What symptoms suggest an upper UTI?

Loin pain

Constitutional symptoms

Fever, rigors, N&V...

32

What type of urine sample is taken to diagnose UTI?

Why?

MIDSTREAM urine sample

First portion of urine will be contaminated by commensals

33

What is an MSU?

Midstream urine sample

34

How long after a urine sample is collected must it reach the lab?

< 2 hours

35

What positives on urinalysis may indicate infection?

Leukocytes

Nitrites

remember dipsticks aren't the ideal investigation

36

Why might positive nitrites indicate a UTI?

Coliforms convert nitrates to nitrites

37

In general, ___ shouldn't be used to investigate UTI.

What should be used instead?

urinalysis

MSU culture

38

More than ___ organisms on microscopy indicates UTI.

105

39

More than ___ organisms on a urine culture indicates infection.

105

40

Which type of growth in a urine culture is probably not significant?

Mixed growth

i.e more than one organism

41

What is abacterial cystitis?

Symptoms of UTI without bacterial growth on culture

42

Why may a patient have abacterial cystitis?

- Early UTI

- Urethral trauma - "Honeymoon cystitis"

- STI

- Patient has taken antibiotics before urine culture collected

43

What is abacterial cystitis associated with urethral trauma also known as?

Honeymoon cystitis

44

How may abacterial cystitis be managed?

Stay hydrated

Good hygiene

Refrain from having sex until symptoms stop

Alkalinise urine (symptomatic relief only)

45

What is asymptomatic bacteriuria?

> 105 organisms in urine but NO SYMPTOMS OF INFECTION

46

How is asymptomatic bacteriuria treated?

What's the exception?

Supportively i.e no antibiotics

Pregnant women are given antibiotics

47

Why are pregnant women given antibiotics if they have asymptomatic bacteriuria?

Complications include:

pyelonephritis

premature labour

growth retardation in child

48

People with catheters are more at risk of UTI.

When would you give antibiotics to someone with bacteriuria and a catheter?

> 105 organisms AND symptoms of infection

49

How do you treat an uncomplicated UTI in women?

Nitrofurantoin OR Trimethoprim (3 days)

50

How do you treat an uncomplicated UTI in men?

Nitrofurantoin OR Trimethoprim (7 days)

51

Which drug could you give to a pregnant women with an uncomplicated lower UTI?

Cefalexin

because trimethoprim is teratogenic in the 1st trimester and nitrofurantoin is teratogenic in the 3rd (but generally alright to use)

52

Why are nitrofurantoin or trimethoprim used to treat lower UTIs only?

They aren't effective in the upper urinary tract

53

How do you treat a complicated UTI or pyelonephritis in primary care?

Co-amoxiclav (14 days)

54

How do you treat a complicated UTI in primary care in a patient who is allergic to penicillin?

Co-trimoxazole (14 days)

55

How do you treat a complicated UTI or pyelonephritis in hospital?

Amoxicillin Gentamicin IV (3 days)

56

If a patient in hospital develops a complicated UTI and you treated them with amoxicillin gentamicin IV for 3 days, what would you then step down to?

Co-trimoxazole PO (4 days)

For a total of 7 days on antibiotics

57

How do you treat a complicated UTI or pyelonephritis, in hospital, in a patient who is allergic to penicillin?

Co-trimoxazole Gentamicin IV (3 days)

then step down to 

Co-trimoxazole PO (4 days)

58

Gentamicin can only be used in hospital - why?

Has to be given IV

59

Is gentamicin safe in pregnancy?

No

60

How is gentamicin dose calculated?

Weight

61

What are possible effects of gentamicin toxicity?

Nephropathy

CN VIII damage - hearing loss, balance problems

62

If a bacterium has beta lactamase, which antibiotics won't work on it?

Penicillins

Cephalosporins

63

Carbapenemase-resistant bacteria are resistant to which antibiotics?

All of them

64

What can be given as an alternative to gentamicin in some patients?

Aztreonam IV

65

In which trimesters should

a) trimethoprim

b) nitrofurantoin

be avoided?

Why drug could be given to a pregnant women with a UTI instead?

a) 1st trimester

b) 3rd trimester

Cefalexin PO

66

What is the combined form of trimethoprim which can be given to patients with complicated UTIs?

What is a rare side effect of using it?

Co-trimoxazole

Stevens-Johnson syndrome (severe blistering disease)