Microbiology of UTI

Question 1

Define:

a) MSSU
b) upper UTI
c) lower UTI
d) cystitis
e) bacteriuria

Answer 1

a) mid-stream sample of urine
b) renal pelvis infection (pyelonephritis)
c) urethra, bladder, prostate infection
d) inflammation (not necessarily infection) of the bladder
e) presence of bacteria in the urine, which may or may not be symptomatic

Question 2

What is the main causal organism associated with UTI?

Answer 2

E.coli (about 70% in the community)

Question 3

What other bacteria may be causal?

Answer 3

Proteus sp.
Staph. saprophyticus
Pseudomonas

Question 4

How might a UTI present? What symptoms suggest involvement of higher structures?

Answer 4

Dysuria, frequency, nocturia, haematuria, suprapubic pain/discomfort

Fever, loin pain, rigors

Question 5

Which dipstick measurements might indicate UTI?

Answer 5

Leukocytes and nitrites

Maybe protein and blood

Question 6

How many bacteria need to be present for a urine culture to be “significant”?

Answer 6

> 10^5

Question 7

How should a mixed growth of 10^5 be regarded?

Answer 7

Probably non-significant

Question 8

How is non-complicated UTI in females treated?

Answer 8

Three days course of trimethoprim or nitrofurantroin

Question 9

How is complicated UTI/pyelonephritis treated?

Answer 9

Co-amoxiclav or co-trimoxazole (14 days)

Question 10

The use of which antibiotic is associated with C. difficule infection?

Answer 10

Ciprofloxacin

Question 11

How is UTI in men treated?

Answer 11

Trimethoprim or nitrofurantroin (14 days)

Question 12

What is the traditional definition of recurrent UTI?

Answer 12

Two within 6 months; or three within a year

Question 13

For patients who suffer from recurrent infections what can be offered in general practice?

Answer 13

Standby prescription

Question 14

What are the antibiotic prophylaxis rules for recurrent UTI

a) related to sexual intercourse
b) unrelated to sexual intercourse?

Answer 14

a) 100mg trimethoprim, one to be taken within 2 hours of sexual intercourse
b) six-month course of low-dose nitrofurantoin or trimethoprim

Question 15

When should referral for imaging or cystoscopy be considered?

Answer 15

Persistent non-responders to treatment

History of renal disease or anomaly

Have haematuria

Question 16

What can ascending infection lead to? (6)

Answer 16

Pyelonephritis
Perinephric and intrarenal abscess
Hydronephrosis
Pyonephrosis
AKI
Sepsis