Comparing the Outcomes of Adults with Enterobacteriaceae Bacteremia Receiving Short-Course vs Prolonged-Course Antibiotic Therapy

BACKGROUND: The recommended duration of antibiotic treatment for Enterobacteriaceae bacteremia is between 7 and 14 days. We compared the clinical outcomes of patients receiving short-course (6–10 days) vs prolonged-course (11–15 days) antibiotic therapy for Enterobacteriaceae bacteremia. METHODS: A retrospective cohort study was conducted at The Johns Hopkins Hospital, The University of Maryland Medical Center, and The Hospital of the University of Pennsylvania including patients with monomicrobial Enterobacteriaceae bacteremia treated with in vitro active antibiotic therapy in the range of 6–15 days between 2008 and 2014. 1:1 nearest neighbor propensity score matching without replacement was performed, prior to regression analysis, to estimate the risk of all-cause mortality within 30 days after the end of antibiotic treatment for patients receiving short vs. prolonged durations of antibiotic therapy. Secondary outcomes included Clostridium difficile infection (CDI) and the emergence of multidrug-resistant Gram-negative (MDRGN) bacteria within 30 days after the end of antibiotic therapy. RESULTS: A total of 1,769 patients met eligibility criteria. There were 385 matched pairs who were well-balanced on baseline characteristics. The median duration of therapy in the short-course group and prolonged-course group was 8 days (interquartile range (IQR) 7–9 days) and 15 days (IQR 13–15 days), respectively. No difference in all-cause mortality between short- and prolonged-course treatment groups was observed (adjusted hazard ratio [aHR] 1.00; 95% CI 0.62–1.63). Rates of CDI were similar between the treatment groups (OR 1.17; 95% CI 0.39–3.51). There was a non-significant protective effect of short-course antibiotic therapy on the emergence of MDRGN bacteria (OR 0.59; 95% CI 0.32–1.09 P = 0.09). CONCLUSION: Short courses of antibiotic therapy yields similar clinical outcomes to prolonged courses of antibiotic therapy for Enterobacteriaceae bacteremia, and may protect against subsequent MDRGN emergence. DISCLOSURES: All authors: No reported disclosures.