Do asymptomatic males with nitrites in their urine require treatment?

Management of Asymptomatic Bacteriuria with Nitrites in Males

Asymptomatic males with nitrites in their urine do not require antimicrobial treatment. 1, 2

Definition and Prevalence

• Asymptomatic bacteriuria in men is defined as a single clean-catch voided urine specimen with one bacterial species isolated in a quantitative count of ≥10^5 CFU/mL, or a single catheterized specimen with ≥10^2 CFU/mL 1
• The prevalence of asymptomatic bacteriuria in men varies by age and comorbidities:
  • Rare in healthy young men 1
  • Increases after age 60 to 3.6-19% in community-dwelling elderly men 1, 2
  • Higher (15-40%) in institutionalized elderly men 1, 2
  • 0.7-11% in men with diabetes 1, 2

Evidence-Based Recommendations

• The Infectious Diseases Society of America (IDSA) explicitly recommends against screening for or treatment of asymptomatic bacteriuria in men without specific risk factors 1, 2
• The presence of nitrites in urine indicates the metabolism of urinary nitrates by certain bacteria (especially gram-negative enteric bacteria), but is not itself an indication for treatment in asymptomatic individuals 1
• Pyuria (white blood cells in urine) accompanying asymptomatic bacteriuria is also not an indication for antimicrobial treatment 1, 2

Clinical Implications of Nitrites

• Nitrite testing has high specificity (true-positive rate) but lower sensitivity (true-negative rate) for detecting bacteriuria 1
• The presence of nitrites is highly specific for urinary infection with only about 1% false positives 3
• Nitrite-positive results may correlate with certain resistance patterns, but this should not guide empiric therapy decisions in asymptomatic patients 4, 5

Exceptions: When Treatment Is Indicated

• The only clear indication for treating asymptomatic bacteriuria in men is before undergoing urologic procedures with risk of mucosal trauma 1, 2
• In these cases:
  • Obtain urine culture before the procedure to guide antimicrobial therapy 2
  • Initiate antibiotics 30-60 minutes before the procedure 2
  • Use short-course therapy (1-2 doses) rather than prolonged therapy 2
  • Discontinue immediately after the procedure if no indwelling catheter is placed 2

Risks of Unnecessary Treatment

• Treatment of asymptomatic bacteriuria in men without specific indications can lead to:
  • Increased risk of symptomatic infections 2
  • Adverse medication effects 2
  • Development of antimicrobial resistance 2
  • Reinfection with more resistant organisms 2

Special Considerations

• For catheterized patients, antimicrobial treatment is not recommended while the catheter remains in situ 1
• For men with spinal cord injuries, treatment of asymptomatic bacteriuria is not recommended regardless of whether they use intermittent catheterization or have indwelling catheters 1
• Elderly institutionalized men should not receive treatment for asymptomatic bacteriuria, even with positive nitrites 1

Diagnostic Considerations

• A positive nitrite test should not be the sole basis for initiating antimicrobial therapy in asymptomatic individuals 4, 5
• The reliability of nitrite testing may be affected by frequency of urination, with more frequent urination potentially leading to more false negatives 3