Impact of Methicillin-Resistant Staphylococcus aureus Prevalence among S. aureus Isolates on Surgical Site Infection Risk after Coronary Artery Bypass Surgery

Abstract

OBJECTIVE-Cephalosporins are recommended for antibiotic prophylaxis to prevent cardiothoracic surgical site infections (SSIs) except in patients with β-lactam allergy or in settings with a "high" prevalence of methicillin-resistant Staphylococcus aureus (MRSA) among S. aureus isolates (hereafter, "MRSA prevalence"); however, "high" remains undefined. We sought to identify the MRSA prevalence at which glycopeptide prophylaxis would minimize SSIs relative to β-lactam prophylaxis.METHODS-We developed a decision analysis model to estimate SSI likelihood when either glycopeptides or β-lactams were used for prophylaxis in cardiothoracic surgery. Event probabilities were derived from a systematic literature review. A similar cost-minimization model was also developed.RESULTS-At 0% MRSA prevalence, SSI probability was 3.64% with glycopeptide prophylaxis and 3.49% with β-lactam prophylaxis. At MRSA prevalences of 10%, 20%, 30%, or 40%, SSI probabilities with glycopeptide prophylaxis did not change, but they were 3.98%, 4.48%, 4.97%, and 5.47% with β-lactam prophylaxis. The threshold of MRSA prevalence at which glycopeptide prophylaxis minimized SSI probability and cost was 3%. In sensitivity analyses, variations in most model estimates only modestly affected the threshold.CONCLUSION-Glycopeptide prophylaxis minimizes the risk of SSIs and cost when MRSA prevalence exceeds 3%. At very low MRSA prevalence (between 3% and 10%), the SSI minimization provided by glycopeptide prophylaxis is small and may be within the error of the model. Given the current MRSA prevalence in most community and healthcare settings, clinicians should consider routine prophylaxis with vancomycin. Our findings may have important policy implications, as benefits in cardiothoracic surgery antibiotic prophylaxis must be weighed against the limitations of increased glycopeptide use. For cardiothoracic surgery, US Centers for Disease Control and Prevention (CDC) guidelines recommend β-lactam antibiotics for perioperative prophylaxis unless the patient has a β-lactam allergy or the institution has a "high" prevalence of methicillin-resistant Staphylococcus aureus (MRSA) among S. aureus isolates (hereafter, "MRSA prevalence"). 2,4 In those circumstances vancomycin, a glycopeptide antibiotic, is the recommended prophylactic agent. However, the guidelines acknowledge that there are no data defining what constitutes a "high" MRSA prevalence.Despite their nearly universal activity against S. aureus strains, glycopeptide antibiotics are considered an alternative choice for prophylaxis for two important reasons. First, glycopeptide use may promote the emergence of vancomycin-nonsusceptible S. aureus. 5,6 Second, vancomycin is inferior to β-lactams for the treatment of serious infections caused by methicillin-susceptible S. aureus (MSSA). [7][8][9] Recently, there has been a global increase in MRSA prevalence, including a rise in community-associated infections among healthy persons without "traditional" risk factors for MRSA infection. [10][11][12][13][1...

Optimal Timing and Antibiotic Prophylaxis in Periprosthetic Joint Infection (PJI): Literature Review and World Consensus (Part Three)

“…For CABG surgery, the authors of two studies have recommended a MRSA prevalence threshold of 3% among infections caused by S. aureus (24)(25)(26). Miller et al (27) suggested that lower rates of MRSA prevalence (e.g.…”

Comprehensive Review of Methicillin-Resistant Staphylococcus aureus

“…63 Current clinical practice guidelines for antimicrobial prophylaxis in surgery, as supported by the American Society of Health-System Pharmacists, the Infectious Diseases Society of America, the Surgical Infection Society, and the Society for Healthcare Epidemiology of America, do recommend a single perioperative dose of intravenous vancomycin instead in those patients known to be methicillin-resistant S. aureus-colonized regardless of preoperative decolonization protocol; glycopeptide (e.g., vancomycin) prophylaxis has only been demonstrated to be cost-effective when used routinely where methicillin-resistant S. aureus prevalence rates exceed 10 percent. 64 In addition, if methicillin-resistant S. aureus postoperative infections become a significant portion of the practicing surgeon's complication rate (as identified by epidemiologically linked clusters of methicillin-resistant S. aureus infections), we recommend active surveillance of the surgeons and health care workers and the patient. A similar protocol for methicillin-resistant S. aureus outbreaks has proven effective in other case series involving soft-tissue infections.…”

Perioperative Antibiotics

“…Several recent studies have developed decision analysis models to determine the threshold of MRSA prevalence at which vancomycin would minimize the incidence and cost of SSI. For CABG surgery, the authors of two studies have recommended a MRSA prevalence threshold of 3% among infections caused by S. aureus …”