Methicillin-susceptible Staphylococcus aureus (MSSA) remains a serious and significant pathogen that is associated with increased morbidity and mortality. Recent retrospective studies have suggested cephalosporins (CEPH), particularly cefazolin or ceftriaxone, have comparable efficacy to antistaphylococcal penicillins (ASP) while offering regimens with less frequent dosing. Thus, patients requiring prolonged treatment may benefit from a CEPH as it is associated with reduced costs and more favorable safety profile. Concern remains for use of cefazolin due to reports of inoculum effect. The objective of this study is to compare outcomes with the use of ASP versus CEPH for treatment of MSSA bacteremia in our institution.
This retrospective study included patients with MSSA bacteremia who were treated with an ASP (nafcillin or oxacillin) or CEPH (cefazolin or ceftriaxone) at our institution between January 2011 and December 2013. Electronic medical and pharmacy records were reviewed for data collection. The primary outcome is clinical cure rate, as defined by clearance of bacteremia and resolution of clinical signs and symptoms of infection. Secondary outcomes included microbiological cure, treatment failure (composite of recurrence of MSSA bacteremia, 30-day mortality, or persistent bacteremia), length of stay, and adverse event rates.
Twenty-nine patients treated with ASP and 85 patients treated with CEPH were included. Most common sources of infection were line-related (23.6%) and osteoarticular (19.0%). Rates of clinical cure were similar between ASP and CEPH groups (69.0% vs 84.7%, p=0.06). However, ASP was associated with higher treatment failure rates versus CEPH (37.9% vs 16.5%, p<0.05), primarily due to higher 30-day mortality rate (17.2% CEPH vs 5.9% ASP, p<0.05). Rates of source control were similar (62.3% vs 58.8%, p=0.79). Adverse event rates were significantly lower in CEPH group (16.0% vs 48.3%, p<0.005). Higher rates of infectious disease consultation were associated with treatment success versus failure (86.5% vs 72.0%, p<0.05).
CEPH appear to be effective alternatives in MSSA bacteremia, as they are associated with similar efficacy, significantly less treatment failure and adverse events in comparison to ASP.
B. N. Vu,
J. E. Williamson, None
P. Chung, None
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