How to treat a patient with bacteriuria (presence of bacteria in urine) and negative leukocyte esterase?

Management of Bacteriuria with Negative Leukocyte Esterase

In patients with bacteriuria and negative leukocyte esterase, treatment should be withheld unless specific urinary symptoms are present, as this likely represents asymptomatic bacteriuria rather than a true urinary tract infection requiring antimicrobial therapy. 1

Diagnostic Interpretation

• The presence of bacteria in urine with negative leukocyte esterase strongly suggests asymptomatic bacteriuria, which is common (10-50%) in elderly populations and does not require treatment 1
• The absence of pyuria (negative leukocyte esterase) has excellent negative predictive value for ruling out true urinary tract infection, approaching 100% in most cases 1, 2
• Leukocyte esterase testing has moderate sensitivity (83%) but limited specificity (78%) for detecting UTIs, making clinical correlation essential 1, 3
• Bacteriuria without pyuria is particularly common with certain organisms such as Klebsiella spp. and Enterococcus spp. 4

Management Algorithm

1. Assess for symptoms of UTI:

   • Look specifically for dysuria, frequency, urgency, fever, gross hematuria, or new/worsening urinary incontinence 1
   • Non-specific symptoms like confusion, functional decline, or malaise alone should not trigger UTI treatment 1, 3

2. If symptomatic:

   • Obtain urine culture before starting antibiotics 1, 3
   • Consider adding nitrite testing, as combined leukocyte esterase and nitrite testing increases sensitivity to 93% 1, 2
   • Choose empiric antibiotics based on local sensitivity patterns while awaiting culture results 5

3. If asymptomatic:

   • Withhold antibiotics regardless of bacteriuria 1, 3
   • Prospective studies show that untreated asymptomatic bacteriuria in residents without long-term indwelling urinary catheters persists for as long as 1-2 years without evidence of increased morbidity or mortality 1

Special Population Considerations

• Elderly/Long-term care residents:

  • Asymptomatic bacteriuria is extremely common (10-50%) and should not be treated 1
  • For catheterized patients, change long-term catheters before collecting specimens, as bacteriuria and pyuria are nearly universal in chronic catheterization 1

• Neutropenic patients:

  • In persons with neutropenia, significant bacteriuria may occur without pyuria, representing an exception to the rule 1

• Patients with suspected urosepsis:

  • In residents suspected of urosepsis (high fever, shaking chills, hypotension), obtain both urine and blood cultures regardless of leukocyte esterase results 1

Antibiotic Selection (if treatment indicated)

• For symptomatic patients requiring treatment, options include:
  • Trimethoprim-sulfamethoxazole for susceptible E. coli, Klebsiella, Enterobacter, Morganella morganii, and Proteus species 5
  • Amoxicillin-clavulanate for complicated UTIs, particularly when resistance is suspected 6
  • Consider local resistance patterns when selecting empiric therapy 5, 4

Common Pitfalls to Avoid

• Treating bacteriuria without symptoms leads to unnecessary antibiotic use, increased resistance, and potential adverse effects 1
• Relying solely on urine culture results without considering clinical presentation and leukocyte esterase results 1, 3
• Attributing non-specific symptoms like confusion or functional decline to UTI without specific urinary symptoms 1
• Failing to consider that certain organisms (Klebsiella, Enterococcus) may cause UTI with less pyuria than E. coli 4