1059. Optimal Duration of Antimicrobial Therapy for Bloodstream Infections due to Gram-Negative Bacilli
Session: Poster Abstract Session: Clinical Infectious Diseases: Bacteremia and Endocarditis
Friday, October 28, 2016
Room: Poster Hall
Background: Appropriate antimicrobial therapy is associated with improved outcomes of patients with gram-negative bloodstream infections (BSI). However, optimal treatment duration with appropriate antimicrobial agents remains unclear based on currently available evidence-based data. This retrospective cohort study examined effectiveness of short (7-10 days) and long (>10 days) courses of appropriate antimicrobial therapy in patients with uncomplicated gram-negative BSI.

Methods: Patients who survived hospitalization for gram-negative BSI without complications at Palmetto Health Richland and Baptist Hospitals in Columbia SC, USA from January 1, 2010 to December 31, 2013 were included in the study. Multivariate Cox proportional hazards regression with propensity score adjustment was used to examine treatment failure, defined as mortality or recurrence within 90 days of BSI.

Results: During the study period, 117 and 294 patients received short and long courses of antimicrobial therapy for uncomplicated gram-negative BSI. Overall, the median age was 67 years, 258 (63%) were women, 282 (69%) had urinary source of infection, and 271 (66%) had BSI due to Escherichia coli. The median treatment duration with appropriate antimicrobial agents was 8.5 and 13.3 days in the short and long course groups, respectively. Patients in both groups received nearly 5 days of intravenous antimicrobial therapy. After adjustment for the propensity to use a short course of antimicrobial therapy, risk of treatment failure was higher in patients receiving short compared to long courses of antimicrobial agents (hazard ratio [HR] 2.6, 95% confidence intervals [CI]: 1.2-5.5, p=0.02). Other risk factors for treatment failure included liver cirrhosis (HR 5.8, 95% CI: 1.9-15.0, p=0.004) and immune compromised status (HR 4.3, 95% CI: 1.6-10.8, p=0.006). Definitive antimicrobial therapy with intravenous or highly bioavailable oral agents was associated with reduced risk of treatment failure (HR 0.3, 95% CI: 0.1-0.7, p=0.006).

Conclusion: The current results support common clinical practice of nearly 2 weeks of antimicrobial therapy for gram-negative BSI.

Avery Nelson, BS1, Julie Ann Justo, PharmD, MS, BCPS-AQ ID2, P. Brandon Bookstaver, PharmD, FCCP, BCPS, AAHIVP2, Joseph Kohn, PharmD, BCPS3, Helmut Albrecht, MD4 and Majdi Al-Hasan, MBBS4, (1)University of South Carolina School of Medicine, Columbia, SC, (2)Department of Clinical Pharmacy and Outcomes Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, SC, (3)Palmetto Health Richland, Columbia, SC, (4)Department of Medicine, Division of Infectious Diseases, University of South Carolina School of Medicine, Columbia, SC


A. Nelson, None

J. A. Justo, None

P. B. Bookstaver, Allergan Pharmaceuticals: Scientific Advisor , Research grant

J. Kohn, None

H. Albrecht, None

M. Al-Hasan, None

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