UTIs Lecture

Question 1

What are the signs and symptoms of lower UTIs?

Answer 1

• frequency of micturition
• urgency to urinate
• dysuria
• suprapubic pain and tenderness
• haematuria
• smelly/cloudy urine

Question 2

What are the signs and symptoms of pelvis and kidney infection?

Answer 2

• loin pain and tenderness
• high fever
• systemically unwell

Question 3

What are the predisposing factors of UTIs?

Answer 3

• obstruction (calculi, tumours, benign prostate hyperplasia)
• vesicoureteral reflux (urine flows in wrong way)
• incomplete bladder emptying (neurogenic, voluntary)
• diabetes, sickle cell, immune compromise
• bladder instrumentation/foreign bodies
• congenital structural abnormalities
• sexual activity, pregnancy

Question 4

What are the host defences of the urinary tract?

Answer 4

• urine (osmolality and pH)
• sloughing of epithelial cells
• urine flow and micturition
• mucosal inhibitors of bacterial adherence
• complement activation
• inflammatory response
• immune responses
• commensals

Question 5

What gram-negative bacteria cause UTIs?

Answer 5

• E.coli
• klebsiella sp.
• proteus mirabilis
• enterobacter sp.
• serratia sp.

Question 6

What are the different types of uropathogenic E.coli and its virulence factors?

Answer 6

Serogroups:

• O (somatic): antigen in cell wall
• K (capsular): capsular antigen

Virulence factors:

• fimbriae (for adhesion)
• K antigen
• haemolysin

Question 7

What are the features of the fimbriae found on E. coli?

Answer 7

• allows for specific adhesion to uroepithelial cells

2 types:

• type 1
• type 2

Question 8

What is the bacterial response to adhesion?

Answer 8

• bacterial machinery is activated by siderophores allowing it to take iron
• growth and reproduction is stimulated
• biofilm formation after monolayer has been formed
• if type 1 fimbriae can become internalised in phagocytes and epithelial cells

Question 9

What is a K antigen and what does it do?

Answer 9

• it is a polysaccharide

- forms a micro-capsule to make it resistant to phagocytosis

Question 10

What is haemolysin and what does it do?

Answer 10

• it is a cytolytic exo-protein

- damages tissue membranes in vivo to cause kidney damage

Question 11

What are the gram-positive bacteria that cause UTIs?

Answer 11

• S. saprophyticus
• S. epidermidis
• enterococcus sp.
• coerynebacteria
• lactobacillus

Question 12

What are the key features of proteus mirabilis?

Answer 12

• has peritrichous flagellae (projecting in all directions)
• produces urease
• has swarming ability

Question 13

What are the key features of S. saprophyticus?

Answer 13

• normal microbiota of female perineum and vagina
• sexual activity increases risk of UTI
• commonly causes community acquired UTIs
• causes symptomatic cystitis

Question 14

What are some other key causative organisms of UTIs?

Answer 14

• candida albicans
• trichomonas vaginalis
• schistosoma haematobium

Question 15

What are the key features of candida albicans?

Answer 15

• fungus
• commensal
• causes candidiasis (thrush)
• opportunisitc pathogen in immunocompromised
• can be associated with antibiotic use

Question 16

What are the key features of trichomonas vaginalis?

Answer 16

• protozoan
• pear shaped flagellate
• pathogenic
• other species are commensal
• can cause trichomoniasis
• less common in males

Question 17

What are the ways of diagnosing UTIs?

Answer 17

• clinical
• urine dipstick
• laboratory diagnosis

Question 18

Describe clinical UTI diagnosis

Answer 18

• primarily based on symptoms and signs
• probability of bacteriuria is around 50-80% if presenting with acute UTI symptoms
• increased to over 90% if dysuria and frequency are both present
• empirical treatment with antibiotic with no need for further testing

Question 19

Who can you use urine dipsticks on for UTI diagnosis?

Answer 19

• women under 65 with no risk factors for a complicated UTI

- children 3 months - 16 years old

Question 20

Who can you not use urine dipsticks on for UTI diagnosis?

Answer 20

• on men
• if person is older than 65 as test becomes more unreliable
• if person has an indwelling catheter

Question 21

What are the indications for urine culture?

Answer 21

• children
• male UTI
• immunosuppressed
• pregnancy
• toxic appearance
• underlying medical/urologic disorder
• recent hospitalisation
• recent instrumentation
• recently on antibiotics
• recent treatment failure

Question 22

What antibiotics are used to treat lower UTIs?

Answer 22

• nitrofurantoin
• trimethoprim
• ciprofloxacin
• pivmecillinam
• amoxicillin/cephalexin (pregnancy)

Question 23

What antibiotics are used to treat pyelonephritis?

Answer 23

• co-trimoxazole
• co-amoxiclav
• ciprofloxacin

Question 24

What are the possible complications of UTIs?

Answer 24

• recurrent infections
• permanent kidney damage from acute/chronic kidney infection
• pyelonephritis due to untreated UTI
• increased risk to pregnant women of delivering low birth weight or premature infants
• urethral narrowing in men from recurrent urethritis previously seen with gonococcal urethritis
• sepsis