What to do if a patient's urine culture shows multidrug-resistant (MDR) bacteria but they have no symptoms?

Management of Asymptomatic Bacteriuria with Multidrug Resistant Bacteria

Asymptomatic bacteriuria (ABU) with multidrug resistant bacteria should NOT be treated, regardless of the resistance pattern, unless the patient belongs to specific high-risk populations where treatment is indicated.

Definition and Prevalence

• Asymptomatic bacteriuria is defined as the presence of bacteria in a properly collected urine specimen from a person without symptoms or signs attributable to urinary tract infection 1
• Prevalence varies by population:
  • Healthy premenopausal women: 1.0-5.0%
  • Elderly persons in long-term care: 25-50% (women), 15-50% (men)
  • Persons with indwelling catheters: 100% with long-term use 1

Key Recommendations for Management

Do NOT Treat in Most Populations

• Do not screen for or treat asymptomatic bacteriuria in patients without symptoms, even if multidrug resistant organisms are present 1
• Do not perform surveillance/screening urine testing, including urine culture, in asymptomatic patients 1
• Treatment of asymptomatic bacteriuria in most populations:
  • Provides no clinical benefit 2, 3
  • Increases risk of antibiotic resistance 4, 5
  • May eliminate protective colonization that prevents symptomatic UTIs 4, 3
  • Contributes to unnecessary antibiotic use and antimicrobial resistance 1, 6

Specific Populations Where Treatment IS Indicated

Only treat asymptomatic bacteriuria in:

1. Pregnant women 1, 2

   • Screen all pregnant women at least once in early pregnancy (around 16 weeks)
   • Treat with appropriate antibiotics based on susceptibility testing
   • Use short-course treatment or single-dose fosfomycin trometamol 1

2. Before urological procedures breaching the mucosa 1, 2

   • Screen and treat before procedures where mucosal bleeding is expected
   • Single-dose preoperative prophylaxis may be sufficient 1

Management Algorithm for Multidrug Resistant Asymptomatic Bacteriuria

1. Confirm true asymptomatic bacteriuria

   • Verify absence of urinary symptoms (dysuria, frequency, urgency)
   • Verify absence of systemic symptoms (fever, flank pain)
   • Confirm significant bacteriuria (≥10^5 CFU/mL) in properly collected specimen

2. Determine if patient belongs to a treatment-indicated group

   • Is the patient pregnant? → Treat
   • Is the patient scheduled for urological procedure with mucosal breach? → Treat
   • All other patients → Do NOT treat

3. If treatment is indicated (pregnant or pre-urological procedure):

   • Select antibiotics based on susceptibility testing
   • Use the narrowest spectrum effective antibiotic
   • Use shortest effective duration (3-5 days for pregnancy, single dose for pre-procedure)

4. If treatment is NOT indicated:

   • Do not administer antibiotics
   • Avoid repeat urine cultures unless symptoms develop
   • Educate patient about true UTI symptoms that would warrant evaluation

Common Pitfalls to Avoid

1. Treating based solely on laboratory results without clinical correlation

   • The presence of bacteria in urine does not automatically indicate infection requiring treatment 1, 6

2. Screening for bacteriuria in asymptomatic patients

   • Routine screening leads to unnecessary antibiotic use and promotes resistance 1

3. Treating asymptomatic bacteriuria in patients with recurrent UTIs

   • Treatment may actually be harmful by disrupting protective colonization 4, 3
   • May select for more resistant organisms 4

4. Confusing asymptomatic bacteriuria with true UTI

   • True UTI requires both bacteriuria AND symptoms attributable to the urinary tract 1
   • In elderly patients, nonspecific symptoms (confusion, falls) should not be attributed to UTI without specific urinary symptoms 1

Remember that antimicrobial stewardship is a critical consideration in managing asymptomatic bacteriuria. Unnecessary treatment contributes to the growing problem of antimicrobial resistance and can cause individual harm through medication side effects and disruption of protective bacterial colonization.