Bacteremia rarely develops from asymptomatic bacteriuria (ASB), and preventative, empiric antibiotic treatment of the presumed urinary source should be reserved for those at particular risk, according to a recent proposal.1
“A personalized, risk-based approach to empiric therapy could decrease unnecessary ASB treatment,” asserts Sonali Advani, MBBS, MPH, Division of Infectious Diseases, Duke University School of Medicine, Durham, NC, and colleagues.
The investigators determined in a cohort study of over 11,000 hospitalized patients with ASB that bacteremia from a presumed urinary source occurred in less than 1% of patients with altered mental status (AMS)—a population in whom empiric, preventative antibiotic treatment is particularly common, despite countering guidelines.2 In contrast to the rare occurrence of bacteremia, over 72% of this population with ASB received empiric antibiotic treatment.
In their 5-year, 68-hospital cohort study of 11,590 hospitalized patients with ASB, only 1.4% developed bacteremia from a presumed urinary source, while 72.2% received empiric antibiotics for urinary tract infection. In the 2016 patients with bacteriuria and AMS but no signs of infection, only 0.7% developed bacteremia.
Risk factors for bacteremia identified on multivariable analysis were: male sex (adjusted odds ratio [aOR] 1.45; 95% CI, 1.02-2.05); hypotension (aOR 1.86, 1.18-2.93); 2 or more systemic inflammatory responses (SIRs) criteria (aOR 1.72, 1.21-2.46); urinary retention (aOR 1.87, 1.18-2.96); fatigue (aOR 1.53, 1.08-2.17); log of serum leukocytosis (aOR 3.38, 2.48-4.61); and pyuria (aOR 3.31, 2.10-5.21).
The investigators cited other studies which suggest that identifying patients whose risk for bacteremia from a urinary source exceeds 2%, “could balance potential under and overtreatment.” In this population, they noted, no single characteristic conferred 2% or greater risk of bacteremia.
“Rather, patients at elevated risk generally had multiple diagnostic findings, comorbidities, or symptoms,” Advani and colleagues observed.
In their analysis, identifying patients with ASB with an estimated 2% risk for bacteremia to inform use of empiric antibiotics would have avoided treatment in the 6323 patients with very low risk (of whom 0.7% [44] had bacteremia). An additional 206 patients with higher risk of bacteremia would have received empirical treatment (of whom 0.5% [1] developed bacteremia).
What You Need to Know
The study suggests adopting a personalized, risk-based approach to antibiotic treatment for asymptomatic bacteriuria (ASB). This approach aims to decrease unnecessary antibiotic use by identifying patients at particular risk for developing bacteremia from a presumed urinary source.
Bacteremia rarely develops from ASB, occurring in less than 1% of hospitalized patients with ASB in the study. Despite this low incidence, a significant proportion of these patients receive empiric antibiotic treatment, highlighting potential overuse of antibiotics in this context.
Various risk factors for bacteremia from a urinary source were identified, including male sex, hypotension, presence of systemic inflammatory response criteria, urinary retention, fatigue, leukocytosis, and pyuria. However, no single characteristic conferred a 2% or greater risk of bacteremia, suggesting the importance of considering multiple factors in assessing individual risk.
“Using these personalized risk estimates would allow us to decrease unnecessary ASB treatment without substantially delaying early empiric therapy tin those at highest risk of bacteremia,” Advani and colleagues advised.
They emphasized that a history of dementia alone is not a risk factor for bacteremia, despite the high prevalence of prescribed empiric antibiotics in that population. In addition, they advised that if patients with altered mentation cannot attest to having signs or symptoms of urinary tract infection, assessments should include SIRs, leukocytosis, and pyuria.
Advani and colleagues acknowledge clinicians’ concern that poor outcomes such as bacteremia are more likely if antibiotics are not started early for ASB. They pointed out, however, that antibiotic treatment of ASB has not been shown to improve clinical outcomes, “and is instead associated with increased health care utilization, adverse drug events, and Clostridioides difficile infection.”
They also note that guidelines suggest a strategy of watchful waiting in patients with AMS and no systemic signs of infection, but recommend empiric antibiotic treatment when there are systemic signs of infection.2
“Our findings support this strategy,” Advani and colleagues indicated, “as patients with systemic signs of possible infection were significantly more likely than those without systemic signs of infection to develop bacteremia.”
References
1. Advani SD, Ratz D, Horowitz JK, et al. Bacteremia from a presumed urinary source in hospitalized adults with asymptomatic bacteriuria. JAMA Netw Open. 2024; 7:e242283. doi.10.1001/jamanetworkopen.2024.2283. Accessed March 19, 2024.
2.Nicolle LE, Gupta K, Bradley SF, et al. Clinical practice guideline for the management of asymptomatic bacteriuria: 2019 update by the Infectious Diseases Society of America. Clin Infect Dis. 2019; 68:e83-e110. doi: 10.1093/cid/ciz021. Accessed March 19, 2024.
