UTIs

Question 1

What are the most common aetiological agents in UTI?

Answer 1

E. coli
Staph saprophyticus
Proteus species

Question 2

Proteus

Answer 2

Gram- rod

Question 3

What are the most common aetiological agents of UTI in hospitals?

Answer 3

Other Gram- rods (e.g. Klebsiella, Pseudomonas) and Gram+ (e.g. enterococcus, other Staph)

Question 4

Can viruses infect the urinary tract?

Answer 4

Yes, but usually asymptomatic

Question 5

What symptoms can a viral UTI produce?

Answer 5

Usually asymptomatic

Can cause haemorrhagic cystitis or renal disease (not classical UTI)

Question 6

How is UTI resisted by the innate immune system?

Answer 6

Transitional epithelium resists colonisation and invasion
Some bacteria don’t like growing in urine
Constant flushing via bladder emptying

Question 7

What are some predisposing factors to UTI?

Answer 7

Short urethra (girls and women)
Sexual intercourse
Colonisation of distal urethra
No circumcision (infant boys)
Incomplete bladder emptying
Catheterisation

Question 8

List 7 virulence factors important in the pathogenesis of UTIs and some organisms which possess them

Answer 8

Adhesins (E. coli)
Polysaccharide capsule (E. coli)
IC bacterial communities
Biofilm formation
Haemolysin (E. coli)
Siderophores for iron acquisition
Urease (e.g. Proteus)

Question 9

What are the main virulence factors relevant to UTI by E. coli and where are they important?

Answer 9

Type I pili in bladder
Flagella to migrate up ureters
PAP pili in kidney

Question 10

How is urine sampled for diagnosis of UTI?

Answer 10

MSU
Catheter/nephrostomy sample
Bag sample
Suprapubic aspirate

Question 11

What lab findings on examination of MSU suggest UTI?

Answer 11

WBCs >10^5/mL
RBCs >10^4/mL
Squamous epithelial cells suggest poorly collected sample
Bacteria >10^5 CFU/mL

Question 12

What lab findings on examination of catheter sample suggest UTI?

Answer 12

Bacteria >10^2 CFU/mL

Question 13

What lab findings on examination of suprapubic aspirate suggest UTI?

Answer 13

Any growth of bacteria is significant

Question 14

What is the important in the handling of MSU samples for investigation of UTI?

Answer 14

Important to transport as quickly as possible or to keep cool, to prevent extra bacterial growth

Question 15

What are the possible causes of sterile pyuria?

Answer 15

Non-infectious conditions
Partial treatment
Difficult to grow bacteria (e.g. TB)

Question 16

What is sterile pyuria?

Answer 16

No bacterial growth with WBCs consistently >10^5/mL

Question 17

How is uncomplicated cystitis treated?

Answer 17

Alkalinise urine

Cephalexin OR co-amoxyclav OR trimethoprim for 3-5 days (14 in men)

Question 18

How is pyelonephritis treated?

Answer 18

Cephalexin OR co-amoxyclav OR trimethoprim for 10 days

If severe sepsis include ampi/amoxycillin + gentamicin

Question 19

When is asymptomatic bacteriuria significant?

Answer 19

In pregnancy