621. Comparative Effectiveness of Cefazolin versus Penicillinase-Stable Penicillins for Treatment of Methicillin-Susceptible Staphylococcus aureus Infections Complicated by Bacteremia: A Nationwide Cohort Study
Session: Oral Abstract Session: Bacteremia and Endocarditis
Thursday, October 8, 2015: 2:15 PM
Room: 32--ABC
Background: Cefazolin is often prescribed instead of penicillinase-stable penicillins (PSP) (e.g. nafcillin or oxacillin) to treat MSSA infections complicated by bacteremia due to its convenient dosing and lower cost. Additionally, adverse events such as cytopenia, rash, renal dysfunction, and liver function abnormalities have been reported in patients receiving PSP. This study compared definitive therapy with cefazolin versus PSP among patients with MSSA infections complicated by bacteremia admitted to Veterans Health Administration hospitals.

Methods: This retrospective cohort study included patients admitted to 121 hospitals from 2003 to 2010. Patients were included if they had a blood culture positive for MSSA and received definitive therapy with cefazolin, nafcillin, or oxacillin. Definitive therapy was the receipt of an antimicrobial between 4 to 14 days after the first positive blood culture was collected. Cox proportional hazard regression and ordinal logistic regression (categories: no recurrence, recurrence, death) were used to examine the association between treatment and mortality or recurrence. Recurrent MSSA bloodstream infections were defined as a MSSA positive blood culture between 45 to 365 days after the first MSSA positive blood culture.

Results: Of 3,303 patients, 2,033 (62%) patients received definitive therapy with PSP. Patients who received cefazolin had a 26% lower 30-day mortality compared to patients who received PSP (Hazard ratios (HR): 0.74; 95% Confidence Intervals (CI): 0.60-0.91) after controlling for severity of illness, comorbidity score, age, skin and soft tissue infections, osteomyelitis, and endocarditis. However, 90-day mortality (HR: 0.93; 95% CI: 0.80-1.09) and the odds of recurrence (Odds Ratio: 1.10; 95% CI: 0.91-1.31) were similar among patients who received cefazolin compared with patients who received PSP, after controlling for those factors.

Conclusion: In this large, multi-center study, outcomes (90-day mortality and recurrence) were similar among patients receiving cefazolin compared with patients receiving PSP for MSSA infections complicated by bacteremia. Given similar outcomes and convenient dosing, physicians might consider cefazolin for MSSA bloodstream infections.

Jennifer Mcdanel, PhD1,2,3, Mary-Claire Roghmann, MD, MS, FIDSA, FSHEA4,5, Eli Perencevich, MD, MS, FIDSA, FSHEA1,2,3, Michael Ohl, MD, MSPH1,2, Michihiko Goto, MD, MSCI1,2, Daniel Livorsi, MD6, Makoto Jones, MD, MS7,8, Justin Albertson, MS1, Rajeshwari Nair, MBBS, MPH1,3, Amy O'shea, PhD1,2 and Marin Schweizer, PhD1,2,3, (1)Iowa City VA Health Care System, Iowa City, IA, (2)University of Iowa Carver College of Medicine, Iowa City, IA, (3)University of Iowa College of Public Health, Iowa City, IA, (4)VA Maryland Healthcare System, Baltimore, MD, (5)University of Maryland School of Medicine, Baltimore, MD, (6)Indiana University School of Medicine, Indianapolis, IN, (7)University of Utah School of Medicine, Salt Lake City, UT, (8)VA Salt Lake City Health Care System, Salt Lake City, UT

Disclosures:

J. Mcdanel, None

M. C. Roghmann, None

E. Perencevich, Cubist Pharmaceuticals, inc: Grant Investigator , Research grant

M. Ohl, None

M. Goto, None

D. Livorsi, None

M. Jones, None

J. Albertson, None

R. Nair, None

A. O'shea, None

M. Schweizer, None

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