Does Topical Vancomycin Powder Use in Fracture Surgery Change Bacteriology and Antibiotic Susceptibilities? An Analysis of the VANCO Trial

Abstract

OBJECTIVE: To determine whether intrawound vancomycin changes the bacteriology of surgical site infection pathogens and investigate the emergence of antibiotic-resistant pathogens. METHODS: Design: Secondary analysis of phase III, prospective, randomized clinical trial. Setting: Thirty-six US trauma centers. Patient Selection Criteria: Patients who became infected after fixation of tibial plateau or pilon fracture. Outcome Measures and Comparisons: Pathogen types and bacterial susceptibilities as determined from routine clinical culture in the operating room. RESULTS: 74 patients were studied that were 67.5% male with a mean age of 48.6 years. A lower proportion of gram-positive cocci was observed in the vancomycin powder compared to the standard of care group (3.7% vs. 8.0%, p=0.01). Methicillin-resistant Staphylococcus aureus (MRSA) infection incidence was comparable in both the vancomycin powder and standard of care groups, but rates of methicillin-susceptible Staphylococcus aureus (MSSA) infections were lower in the treatment group (1.4% vs. 4.8%, p=0.01). The incidence of coagulase-negative Staphylococci (CoNS) and gram-negative rod infections were similar in both groups. There was no significant difference in susceptibilities between groups in rates of vancomycin-resistant enterococcus. CONCLUSION: Topical vancomycin powder decreases the likelihood of gram-positive infections consistent with the biologic activity of vancomycin. Fewer MSSA and CoNS infections were observed in the group treated with vancomycin powder. An effect of vancomycin powder on MRSA infection risk was not detected given the low incidence in both the intrawound vancomycin and standard of care groups. There was no emergence of gram-negative rod infections or increased resistance patterns observed. Use of topical vancomycin powder does not appear to produce infections in these patients with greater antibiotic resistance than would have occurred without its use.