219. Characteristics Associated with Inappropriate Antibiotic Prescribing in Patients with Asymptomatic Bacteriuria (ASB)

Background Antibiotic treatment of asymptomatic bacteriuria (ASB) is considered inappropriate, does not improve patient outcomes, and may lead to adverse events such as antibiotic resistance and Clostridioides difficile infection. Previous stewardship interventions have focused on reducing unnecessary urine culture collection in individuals without urinary symptoms; however, further interventions to reduce inappropriate prescribing in ASB are warranted. This study sought to identify characteristics associated with treatment of ASB in order to implement future stewardship interventions. Methods This two-center, retrospective cohort study included unique emergency department or inpatient adults with consecutive non-duplicate monomicrobial urine isolates of Enterobacterales or Pseudomonas aeruginosa collected between 8/2013 and 1/2014 from two academic hospitals in Boston, Massachusetts. Patients with ASB (without chart-documented urinary-specific symptoms) were identified through chart review and stratified into two groups: those treated with empiric urinary tract infection (UTI) antibiotics and those untreated. Logistic regression analyses were performed to identify variables independently associated with antibiotic treatment of ASB. Results During the study, 255 patients were determined to have ASB and a majority (80.8%) were treated with empiric UTI antibiotics. Most patients were female (71.4%) and elderly (mean age 70 years). The most common organisms isolated were Escherichia coli (59.2%), Klebsiella spp. (23.1%), and P. aeruginosa (9.8%). The presence of isolated fever (OR, 7.83 [95% confidence interval, 1.51, 144.20]); p = 0.05), urinalysis positive for pyuria (>10 white blood cells) (OR, 2.52 [95% CI, 1.15, 5.54]; p = 0.02), and Klebsiella spp. urine isolate (OR, 2.99 [95% CI, 1.19, 8.60]; p = 0.02) were independently associated with treatment. Conclusion A large proportion of ASB patients were treated with antibiotics despite clinical practice guidelines recommending against this practice. Isolated fever, pyuria, and Klebsiella spp. culture were all significantly associated with the treatment of ASB; targeted review of these patients by stewardship programs may help to reduce inappropriate ASB treatment within these institutions. Disclosures Elizabeth B. Hirsch, PharmD, Merck (Grant/Research Support) Nabriva Therapeutics (Advisor or Review Panel member)