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Internal Medicine

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Bacteremia from Asymptomatic Bacteriuria Is Both Rare and Hard to Predict

Rahul B. Ganatra, MD, MPH, reviewing Advani SD et al. JAMA Netw Open 2024 Mar 4

Despite guideline recommendations against antibiotics for asymptomatic bacteriuria (ASB; NEJM JW Emerg Med Jun 2019 and Clin Infect Dis 2019; 68:e83), antibiotic treatment for patients with ASB and nonspecific symptoms remains common. In this retrospective study, researchers estimated the prevalence of bacteremia from a urinary source (i.e., isolation of identical organisms from blood and urine cultures collected within 3 days of each other) among 11,600 hospitalized noncritically ill adults with ASB at 68 hospitals in Michigan; data were obtained by standardized review of individual charts and were not simply administrative data. Patients with specific signs or symptoms of urinary tract infection (UTI) and patients who received antibiotics for UTI before blood culture collection were excluded.

Key findings were as follows:

  • Among all patients with ASB (median age, 78; 75% women; 15% with indwelling urinary catheters), 72% received antibiotics, whereas only 1.4% developed bacteremia.

  • Among the 44% of patients with ASB who also had altered mental status (AMS), rates of bacteremia were similarly low (1.8%).

  • Male sex, hypotension, ≥2 systemic inflammatory response syndrome (SIRS) criteria, urinary retention, fatigue, leukocytosis, and pyuria (>25 white blood cells per high-power field) were all associated with bacteremia, although none identified risk for bacteremia exceeding 2%.

  • Older age, AMS, dementia, and change in urine color or odor were not associated with bacteremia.


This study raises the question of whether personalized estimation of a patient's risk for bacteremia from ASB could prevent inappropriate antibiotic use. Until risk calculators are developed, this study should reassure clinicians that bacteremia is extremely uncommon among patients with ASB who lack evidence of systemic infection. The findings also suggest we should think twice before starting antibiotics in hospitalized patients who have positive urinary cultures but no urinary symptoms and no symptoms or signs that are worrisome for bacteremia.


Advani SD et al. Bacteremia from a presumed urinary source in hospitalized adults with asymptomatic bacteriuria. JAMA Netw Open 2024 Mar 4; 7:e242283. ( opens in new tab)

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