UTI

Question 1

Which group of patients are at risk of urinary tract infection?

Answer 1

1. child <3 yr old (underlying abnormalities eg spina bifida, vesicourethral reflux)
2. yg female
3. elderly
4. catheterised pt (hosp/stroke)
5. underlying abnormalities

Question 2

What are the predisposing factors for urinary tract infections?

Answer 2

1. reflux - vesicourethral angle not acute
2. calculi
3. prostatism
4. congenital
5. catheter
6. neurological
7. pathogen factors (attachment, type 1, P fimbriae)

Question 3

What are the 2 sites of UTI?

Answer 3

1. Upper UTI (pyelonephritis)
2. Lower UTI (cystitis)

• bacteraemia = upper tract infection

Question 4

What are the likely pathogens?

Answer 4

1. E coli

2. Staphylococcus saprophyticus

Question 5

In pt w structural anomalies/ catheter, what kinds of UTI pathogens are common?

Answer 5

1. Proteus
2. Pseudomona aeruginosa
3. Enterococcus
4. candida

Question 6

Where should you collect urine specimen?

Answer 6

1. catheterised pt: collect from port and not from bag

2. clean catch urine

Question 7

What should you do when collecting urine specimen?

Answer 7

1. Clean adequately
2. Collect before antibiotics
3. Transport immediately to lab

Question 8

What is a screening tool for UTI?

Answer 8

Urine dipstick

• rbc (haem),
• wbc (leukocyte esterase),
• nitrates (E coli metabolites)
• note but err on oversensitivity so need microscopy

Question 9

What are the possible findings of urine microscopy?

Answer 9

1. Hematuria: RBC > 100/uL + WBC > 100/uL

2. Pyuria: WBC > 100/uL + RBC <10/uL

Question 10

If WBC count is low, does it mean patient does not have UTI?

Answer 10

No, as

1. dilution effect
2. WBC degraded on storage

Question 11

Diagnosis of UTI using urine culture

Answer 11

1. Single colony + >100,000 cfu/mL : significant
2. 1000-100,000 cfu/mL + single colony: may also be significant

• mainly gram -ve

Question 12

How do you know if urine culture is inaccurate?

Answer 12

1. Mixed growth
2. Overgrowth if > 90min storage & transport –> false positives
3. Non pathogenic species eg coagulase-negative staph

so need to take into account
Bacterial count
Mixed / single organism
Presence or absence of catheter
Patient’s age and background

Question 13

What’s needed to diagnose UTI?

Answer 13

Any 2 of 3

1. Symptoms
2. Urine WBC ++ pyuria
3. Culture ++ growth

Question 14

How long do you treat uncomplicated UTI?

Answer 14

3 days

Question 15

How long do you treat upper tract infection?

Answer 15

at least 2 weeks

• look for underlying abnormalities

Question 16

What are the empiric antibiotics for UTI?

Answer 16

1. Cotrimoxazole
2. Amoxy-clavulanic acid
3. Cephalosporins
4. Aminoglycosides
5. Fluoroquinolones

Question 17

What are the antibiotics ONLY used for lower tract UTI?

Answer 17

1. Nitrofurantoin

2. nalidixic acid

Question 18

What are the antibiotics used for uncomplicated UTI?

Answer 18

Oral cephalosporins

Question 19

Antibiotics not for X urinary infection

Answer 19

Erythromycin &

Clindamycin

Question 20

Special cases

Answer 20

Pyelonephritis
Recurrent UTI
Paediatric UTI
Catheter-associated UTI
Asymptomatic bacteriuria

Question 21

Sexually-transmitted diseases

Answer 21

Ulcer
Syphilis *
Haemophilus ducreyi
Herpes simplex virus

Discharge
Neisseria gonorrhoeae *
Chlamydia trachomatis *

Warts
Human papillomavirus

Systemic
HIV, hepatitis B

Others
lymphogranuloma venerum

Question 22

What are the tests for syphilis?

Answer 22

Treponema:

1. TPHA
2. EIA

Non-treponema:
1. VDLR

Rapid plasmid reagin:
RPR

Question 23

Which would be the syphilis screening test recommended?

Answer 23

TPHA/EIA as life long positives

Question 24

What must you take note of if TPHA/EIA used to screen for syphilis?

Answer 24

Cross-reactivity with non-syphilis treponema infection

eg yaws

Question 25

Why not use VDLR or RPR to screen for syphilis?

Answer 25

1. biological false positives 2. false negatives due to pro-zone 3. more used to monitor disease activity

Question 26

How do you screen for Neisseria gonorrhea?

Answer 26

Lab tests: 1. Culture on Thayer-Martin agar (use Amies transport media +/- charcoal) 2. PCR, usually w chlamydia PCR - replace culture but no info on susceptibility

Question 27

Treatment of N gonorrhea

Answer 27

high prevalence of penicillin resistance (penicillinase + PBP) 1. ceftriaxone (emerging resistance) 2. alt: azithromycin 3. X ciprofloxacin 4. concurrent chlamydia: doxycycline

Question 28

How do you screen for chlamydia?

Answer 28

screen sex active women -- 25 yr old 1. CT PCR (cyclic threshold-CT) 2. endocervical, vagina, urine specimens

Question 29

Treatment of chlamydia

Answer 29

doxycycline | azithromycin

Question 30

What are the causes of vaginal discharge?

Answer 30

1. candida 2. bacterial vaginosis (gram stain, VP3 DNA probe test) 3. trichomonas vaginalis (wet mount, PCR)

Question 31

Reasons for a negative culture but with UTI symptoms and pyuria

Answer 31

1. Started on antibiotics 2. “acute urethral syndrome” - Due to chlamydia, other organisms - With symptoms, may respond to treatment 3. Others e.g. TB

Question 32

What measures can be taken to overcome the problem of prolonged transport time for urine?

Answer 32

Keep in fridge 4 deg C – send within 24 h Boric acid in container (supplied by lab) Urine dipslide