Comparison of outcomes in patients with methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia who are treated with β-lactam vs vancomycin empiric therapy: a retrospective cohort study.
BMC Infect Dis. 2016 May 23;16(1):224.
Wong D1, Wong T2,3, Romney M2,4, Leung V2,4.
1PGY-V Infectious Diseases Residency Training Program, University of British Columbia, Vancouver General Hospital, D 452 Heather Pavilion, 2733 Heather Street, Vancouver, BC, V5Z 1 M9, Canada. email@example.com.
2Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada.
3Division of Medical Microbiology and Infection Control, Vancouver General Hospital, JPPN1, Medical Microbiology Laboratory, 899 W 12th Ave, Vancouver, BC, V5Z 1 M9, Canada.
4Division of Medical Microbiology, St. Paul’s Hospital, Medical Microbiology Laboratory, 1081 Burrard St., Vancouver, BC, V6Z 1Y6, Canada.
Prior studies suggested that vancomycin may be inferior to β-lactams for the empiric treatment of methicillin-susceptible S. aureus (MSSA) bacteremia. We assessed whether empiric therapy with β-lactams compared to vancomycin was associated with differences in clinical outcomes in patients with MSSA bacteremia.
We conducted a retrospective cohort study of adult inpatients with their first episode of MSSA bacteremia at two tertiary care hospitals in Vancouver, Canada, between 2007 and 2014. Exposure was either empiric β-lactam or vancomycin therapy. All patients received definitive treatment with cloxacillin or cefazolin. The primary outcome was 28-day mortality. Secondary outcomes were 90-day mortality, recurrent infection at 6 months, duration of bacteremia and hospital length-of-stay. Outcomes were adjusted using multivariable logistic regression.
Of 814 patients identified, 400 met inclusion criteria (β-lactam = 200, vancomycin = 200). Overall 28-day mortality was 8.5 % (n=34). There were more cases of infective endocarditis in the β-lactam than in the vancomycin group [45 (22.5 %) vs 23 (11.5 %), p < 0.01]. Adjusted mortality at 28 days was similar between the two groups (OR: 1.14; 95 % CI: 0.49-2.64). No differences in secondary outcomes were observed. Transition to cloxacillin or cefazolin occurred within a median of 67.8 h in the vancomycin group.
Empiric therapy with β-lactams was not associated with differences in all-cause mortality, recurrent infection, microbiological cure or hospital length-of-stay compared to vancomycin. Vancomycin monotherapy may be appropriate for the empiric treatment of MSSA bacteremia if definitive therapy with cloxacillin or cefazolin can be initiated within 3 days