Abstract 18859: Staphylococcus aureus Infective Endocarditis is Associated with Worsened Clinical Characteristics than Non-Staphylococcus aureus Organisms

Abstract

Background: Staphylococcus aureus remains a leading cause of IE, but it is unknown whether S. aureus is associated with more severe infections or worsened outcomes compared to other bacterial organisms. The primary purpose of this study was to compare the clinical characteristics and mortality in S. aureus (SA) versus non-S. aureus (NSA) IE patients undergoing valvular surgery. Methods: All patients undergoing valvular surgery for bacterial IE between 1995 and 2013 at our institution were included in this study. Clinical data were retrospectively collected from chart review. Patients were categorized according to causative organism: 1) SA: n=85, and 2) NSA: n=238, composed of coagulase-negative staphylococci (23%), streptococci (12% viridans; 19% non-viridans), enterococci (17%), and other (51%). Results: SA patients had a higher severity of illness compared to NSA patients due to higher rates of preoperative vascular complications (58.8% vs. 39.4%, p = 0.002), preoperative septic shock (23.5% vs. 13.9%, p = 0.039), preoperative embolic events (33.3% vs. 20.7%, p = 0.02), preoperative stroke (27.1% vs. 13.5%, p = 0.004), and annular abscess (44.7% vs. 27.3%, p = 0.003). There were no statistically significant differences in 30-day (9.4% vs. 8.0%, p = 0.68, OR = 1.20) or 1-year (20% vs. 14.3%, p = 0.22, OR = 1.50) post-operative mortality between SA and NSA IE patients, respectively. However, length of hospital stay, and 30-day post-operative development of new renal failure were higher in SA patients. There was a trend to more post-operative embolic events in SA patients. Conclusions: SA IE is associated with higher morbidity on presentation, such as pre-operative embolic events, stroke and annular abscess, compared to IE caused by other bacterial organisms, but does not lead to increased mortality after surgery. Further research is needed to investigate the differences in post-operative complications among patients.