Urinary tract infection Flashcards

1
Q

What is UTI

A

Presence of microorganisms in urinary tract not due to contamination
Present as broad spectrum of clinical entities

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2
Q

What are some routes of infection for UTI?

A
  • Ascending: Colonic/fecal flora colonise periurethra area and ascend to bladder and kidney, higher risk in females
  • Descending: Organism at distant primary site (heart valve, bone) –> bloodstream –> urinary tract
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3
Q

Factors determining development of UTI

A
  • Competency of natural host defence mechanisms
  • Size of inoculums
  • Virulence/pathogenicity of microorganims (common for all infections)
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4
Q

Host defence mechanisms:

A
  • Bacteria in bladder stimulates micturition with increased diuresis –> emptying of bladder
  • Antibacterial properties of urine and prostatic secretion
  • Antiadherence mechanisms of bladder
  • Inflammatory response with polymorphonuclear leukocytes
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5
Q

Risk factors for UTI:

A
  • Females > males
  • Sexual intercourse
  • Abnormalities of urinary tract –> can cause urine to flow back into kidneys to give pyelonephritis
  • Neurologic dysfunctions
  • Anticholinergic drugs
  • Catheterisation and other mechanical instrumentation
  • Diabetes
  • Pregnancy
  • Use of diaphragms and spermicides
  • Genetic association
  • Previous UTI
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6
Q

Prevention of future UTI:

A
  • Drink lots of fluid to flush bacteria –> 6-8 glass/day –> do not drink this much if there are other underlying health problems
  • Urinate frequently and go when the urge comes
  • Urinate shortly after sex to flush bacteria that may have entered urethra
  • After using toilet, wipe from the front to the back especially after bowel movement
  • Wear cotton underwear and loose fitting clothes to keep area dry
  • Avoid tight-fitting jeans and nylon underwear
  • Diaphragm/spermicide use can increase bacteria growth
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7
Q

Classification of UTI:

A
  • Complicated: associated with conditions increasing potential for serious outcomes, with risk of therapy failure
  • Uncomplicated: Usually in healthy premenopausal, non-pregnant women with no history suggestive of abnormal urinary tract

Main classifications include:

  • Uncomplicated cystitis
  • Community acquired pyelonephritis in women
  • Community acquired UTI in men
  • Nosocomial/healthcare-associated pylonephritis
  • Catheter-associated UTI
  • UTI in pregnancy
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8
Q

Subjective symptoms of UTI:

A
  • Cystitis: Dysuria, urgency, frequency, nocturia, suprapubic heaviness/pain, gross hematuria
  • Polynephritis: Fever, rigours, headaches, nausea, vomiting, malaise, flank pain, costovertebral tenderness or abdominal pain
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9
Q

Objective symptoms of UTI. What are the methods to collect urine to use it for analysis?

A
  1. UFEME (WBC, WBC casts, RBC, micro-organisms)
  2. Nitrite presence and leukocyte esterase tests

Above 2 confirmed via urine collection for analysis. Collection methods:

  1. Midstream clean catch
  2. Catheteherisation
  3. Suprapubic bladder aspiration
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10
Q

Likely pathogens for UTI:

A
Uncomplicated/community acquired: 
- E. Coli
- S. saprophyticus 
- Enterococcus faecalis, Klebsiella pneumonia, Proteus spp.
Complicated/healthcare associated: 
- E. Coli 
- Enterococci 
- Proteus, Klebsiella, Enterobacter, P. aeruginosa
Miscellaneous: 
- S. Aureus 
- Yeast/Candidia
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11
Q

When do you need to treat the UTI?

A
  1. UTI presenting with symptoms
  2. For asymptomatic UTI, treat ONLY IF:
    - Patient is pregnant (reduce risk of pyelonephritis, preterm labour and low birth weight infant)
    - Patients going for invasive urologic procedures with mucosal trauma (given as prophylaxis for bacteremia)
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12
Q

First-line antibiotics for uncomplicated cystitis in women:

A
  • PO cotrimoxazole 160/800 mg BD for 3 days
  • PO nitrofurantoin 50mg QID for 5 days
  • PO fosfomycin 3g single dose

Fosfomycin and cotrimoxazole more effective than nitrofurantoin

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13
Q

Empiric antibiotics for community acquired pyelonephritis in women

A
  • PO ciprofloxacin 500 mg BD for 7 days
  • PO levofloxacin 750mg OD for 5 days
  • PO cotrimoxazole 160/800 mg BD for 14 days
  • PO ß-lactam for 10-14 days (PO cephalexin 500 mg BD, PO amoxicillin-clavulanate 625 mg TDS)
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14
Q

Empiric antibiotics for community acquired UTI in men:

A
  • Same as treatment for women if no concern for prostitis
  • If there is concern for prostitis and pyelonephritis for 10-14 days:
    PO ciprofloxacin 500mg BD
    PO cotrimoxazole 800/160 mg BD
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15
Q

Empiric antibiotics for nosocomial/healthcare-associated pyelonephritis

A
  • IV cefepime 2g q12h +/- amikacin 15 mg/kg/day
  • IV imipenem 500mg q6h or IV meropenem 1g q8h
  • PO levofloxacin 750mg BD (less sick patients)
  • PO ciprofloxacin 500mg BD (less sick patients)
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16
Q

What are catheter-associated UTIs?

A
  • Presence of symptoms/signs compatible with UTI with no other identified source of infection along with 10^3 cfu/mL of ≥ 1 bacterial species in single catheter specimen in patients with indwelling urethral, indwelling suprapubic, intermittant catheterisation
  • Most common cause of nosocomial UTI
17
Q

Risk factors of catheter-associated UTIs:

A
  • Duration of catheterisation
  • Colonisation of drainage bag, catheter and periurethral segment
  • DM
  • Female
  • Renal function impairment
  • Poor quality of catheter care
18
Q

Treatment for catheter-associated UTIs:

A
  • Start empiric antibiotics, adjust when culture and sensitivity available
    IV imipenem 500mg q6h
    IV meropenem 1g q8h
    IV cefepime 2g q12h +/- IV amikacin 15mg/kg
    PO/IV levofloxacin 750mg for 5 days (mild catheter- associated UTI)
    PO cotrimoxazole 960 mg BD for 3 days
19
Q

How to prevent catheter-associated UTI?

A
  • Avoid unecessary catheter use
  • Use for minimal duration
  • Long-term indwelling catheters changed before blockage is likely to occur
  • Use of closed system
  • Ensure aseptic insertion technique
  • Topical antiseptic/antibiotics not recommended
  • Prophylactic antibiotics and antiseptics not recommended
  • Chronic suppressive antibiotics not recommended
20
Q

Antibiotics avoided in pregnancy:

A
  • Ciprofloxacin
  • Cotrimoxazole in 1st and 3rd trimester
  • Nitrofurantoin at term
  • Aminoglycosides
21
Q

1st line treatment of UTI in pregnancy

A

ß-lactams

22
Q

Adjunctive therapy for UTI:

A
  • Pain/fever –> paracetamol/NSAIDs
  • vomiting –> rehydration therapy
  • Phenazopyridine –> analgesic effect on urinary tract mucosa to provide symptomatic relief (should not be used in G6PD deficiency)
23
Q

Non-antimicrobial options:

A
  • Cranberry juice
  • Intravaginal estrogen cream
  • Lactobacillus probiotics
24
Q

Goal and monitoring of therapeutic responses:

A
  • Resolution of signs and symptoms within 3 days after initiation of effective antibiotics. Further investigation needed if persistently positive blood cultures
  • Bacteriological clearance –> repeat culture not required for patients who responded. Sometimes culture needed to document clearance of infection (pregnant women)
  • Absence of ADR and allergies
25
Q

When should urine cultures be obtained in UTI?

A

Obtained in all UTI except for uncomplicated cystitis

26
Q

When is a relapse of UTI considered recurrent?

A

Relapse within 2 weeks

27
Q

A urine culture contains S.aureus. What is the likely cause of the presence of S.aureus?

A

Bacteremia. Consider other site of infection

28
Q

Type of bacteria to cover in nosocomial pyelonephritis

A
  • Gram-negs (e.g. P.aeruginosa)

- Resistant strains (E.g. ESBL E.coli, Klebsiella)

29
Q

Causative organisms of CAUTI

A
  1. Short-term catheter (<7d) : usually single, simple organism like E.coli and Klebsiella
  2. Long-term catheter (>28d): usually polymicrobial
30
Q

Duration of treatment of UTI in pregnancy

A
  • Asymptomatic bacteriuria/cystitis: 7d

- Pyelonephritis: 14d

31
Q

Duration of treatment if prostatitis is confirmed in male UTI?

A

6 weeks

32
Q

Duration of treatment of nosocomial pyelonephritis?

A

7-14d

33
Q

General duration of treatment for CAUTI?

A
  • 7d for those with prompt response

- 10-14d for those with delayed response

34
Q

Antibiotics that have to be used with caution in renal insufficiency:

A
  • Nitrofurantoin not for CrCL <30 ml/min
  • Fosfomycin not for CrCL<30mL/min
  • Cotrimoxazole avoid in CrCL <15 mL/min