513. Staphylococcus aureus (SA) Infections after Elective Cardiac Surgery: Observations from a Multicenter Placebo-Controlled Trial of an Investigational Vaccine (ClinicalTrials.gov NCT00518687)
Session: Poster Abstract Session: Surgical Site Infections
Thursday, October 3, 2013
Room: The Moscone Center: Poster Hall C
  • 179878-2225_RSCH_IDSA-Poster_dinubile_V2_FINAL.pdf (300.1 kB)
  • Background:   SA infections following cardiac surgery are under increased scrutiny from payers & considered non-events by Medicare. Implementation of pay-for-performance measures governing postoperative infections has further spurred interventions to prevent this serious complication. 


    Methods:   From 2007-2011, an international, double-blind, randomized placebo-controlled trial of a novel SA vaccine (V710; Merck) was conducted in 7664 adults scheduled for full median sternotomy. Conduit harvesting techniques, perioperative antibiotic prophylaxis, & other interventions were not standardized across the 164 sites. We analyzed the incidence, timing, risk, & consequences of SA infections developing up to 360 days postoperatively in 3832 placebo recipients.

    Results:   The incidence of SA infection was 3.1% (120/3832); bacteremic, deep sternal-wound, and/or other invasive infections occurred in 1% (39/3832) (Table). MSSA & MRSA accounted for 81% (97/120) & 19% (23/120) of infections, respectively. All-cause mortality was 4.1% (153/3712) in patients without SA infection, 7.2% (7/97) in MSSA patients, & 17.3% (4/23) in MRSA patients (p<0.01). Compared to patients without SA infection, patients with SA infections more often had BMI ³30kg/M2 (42% [51/120] vs 25% [939/3712], p<0.001) & diabetes (40% [48/120] vs 24% [878/3712], p<0.001), with 57% (13/23) of MRSA infections occurring in diabetics. MRSA was more often invasive & developed later than MSSA infections (median postoperative day 40 vs 28, p>0.05). SA nasal carriage was detected preoperatively in 18.3% (701/3832) placebo recipients, including 1.6% (60/3832) colonized with MRSA. In patients with & without SA infection, respective baseline nasal colonization rates were 41% (49/120) & 18% (652/3712) (p<0.001). SA infections developed postoperatively in 49/701 (7.0%) colonized patients at baseline vs 71/3131 (2.3%) patients without colonization (relative risk [95% CI] = 3.1[2.2, 4.4]).


    Conclusion: In the modern era, invasive SA infection occurred in1% of adult patients following elective cardiac surgery with an attributable mortality rate of 3% for MSSA & 13% for MRSA infections. The cost/benefit of strategies to reduce this incidence, such as nasal cultures & decolonization, warrants further investigation. 

    Keith B. Allen, MD1, Vance Fowler, MD2, James S. Gammie, MD3, Jonathan Hartzel4, Matthew Onorato4, Mark Dinubile4 and Ajoke Sobanjo-Ter Meulen4, (1)Cardiothoracic and Vascular Surgery, St. Luke's Mid-America Heart and Vascular Institute, Kansas City, MO, (2)Duke University Medical Center, Durham, NC, (3)Cardiac Surgery, University of Maryland, Baltimore, MD, (4)Merck Sharp & Dohme, Corp., Whitehouse Station, NJ


    K. B. Allen, Merck: Investigator, Research support

    V. Fowler, Merck: Investigator, Research support

    J. S. Gammie, Merck: Investigator, Research support

    J. Hartzel, Merck: Employee, Salary

    M. Onorato, Merck: Employee, Salary

    M. Dinubile, Merck: Employee, Salary

    A. Sobanjo-Ter Meulen, Merck: Employee, Salary

    Findings in the abstracts are embargoed until 12:01 a.m. PST, Oct. 2nd with the exception of research findings presented at the IDWeek press conferences.