6. UTI

Question 1

What is a UTI?

Answer 1

• an uncomplicated UTI
• microbial colonisation of the UT by pathogenic micro-organisms
• can be ascending or descending
• endogenous; non-communicable
• can be ‘complicated’ or ‘uncomplicated’

Question 2

What is significant bacteriuria?

Answer 2

• presence of bacteria/ ml of urine
• may be symptomatic/ asymptomatic (in pregnancy)

Question 3

What is cystitis?

Answer 3

• infection of the bladder
• generally ascending
• syndrome of frequency
• Dysuria
• Foul smelling / bloodstained urine

Question 4

What is acute pyelonephritis?

Answer 4

• infection of one or both of the kidneys
• ascending
• descending
• fever, chills, dysuria

Question 5

What is a recurrent UTI?

Answer 5

• may be relapse or reinfection
• relapse; recurrent UTI caused by same microorganism causing original UTI
• reinfection; recurrent UTI caused by different microorganism

Question 6

What are some statistics regarding UTIs?

Answer 6

• 5% women have UTI per year
• 50% women will have a UTI during their lifetime
• 20% of non-pregnancy women with a UTI will have a recurrent infection

Question 7

What are microorganisms associated with community UTI?

Answer 7

80% E.coli
10% Staphylococcus saprophyticus
10% proteus mirabilis

Question 8

What are microorganisms associated with hospital UTI?

Answer 8

50% E. coli
40% Proteus sp, Klebsielle sp, Enterobacter sp
10% S. aureus, C. albicans

Question 9

What are etiological agents of UTI?

Answer 9

• viral; CMV
• fungi; Candida species
• parasites; Schistosoma haematobium
• mycobacterium tuberculosis; HIV
  (predominantly in females)

Question 10

What is the pathogenesis of UTI? (E. coli virulence factors)

Answer 10

• UTIs associated with specific serotype of E.coli (UPEC) based on O, F and K antigens
• Attachment: Fimbriae; 100-400 per bacterium
• Avoidance of host defence: polysaccharide capsule
• Production of exocellular factors; haemolysin; sidephores

Question 11

What are treatments for UTI?

Answer 11

• always requires antibiotics
• bacteriuria; in preschool with vesicoureteric reflux VUR and pregnant women (always give antibiotics)
• urine sample for analysis

Question 12

What clinical samples are collected prior to antibiotic treatment?

Answer 12

• MSU; main stream urine in container with boric acid (red top)
• Bag-urine/ supraphubic aspiration (neonates)
• Catheter specimen of urine (CSU)

Question 13

How can UTI be prevented? (non-specific therapy)

Answer 13

• low dose antibiotic; nitrofuantin 5-100mg at night
• cleanse genitals before sexual intercourse
• antibiotic after sexual intercourse
• drink plenty of water
• cranberry juice contains condensed tannins

Question 14

How can you identify UTI from light microscopy?

Answer 14

presence of WBC and high numbers of bacteria is suggestive of UTI

Question 15

How can you identify E.coli from a biochemical test?

Answer 15

positive:
- indole test
- LDC/ODC
- fermentation of glucose

negative:
- urease
- citrate
- gelatin

Question 16

What is a semi-quantitative culture used for UTIs?

Answer 16

2microlitre of MSU cultured onto CLED (cystine-lactose-electrolyte deficient) - blue
- selective/differential agar
- E.coli is a lactose fermenting colony - yellow

Question 17

What is sterile pyuria?

Answer 17

• renal tuberculosis
• urethritis
• vaginitis (vaginal discharge)