Sternal wound infections in cardiac surgery: effects of vancomycin prophylaxis

Introduction

Appropriate antibiotic prophylaxis plays a crucial role in preventing sternal wound infection after cardiac surgery [1]. In institutions with high prevalence of methicillin-resistant Staphylococci species, vancomycin prophylaxis is recommended either as a monotherapy or as an adjuvant agent [2]. In our study, we assessed sternal wound infection rates before and after the introduction of a vancomycin prophylaxis protocol.

Methods

Twenty-six of a total 227 consecutive cardiac surgical patients, between July and December 2012, developed sternal wound infection (Group A). All of the patients received a standard empirical antibiotic prophylaxis. From January to July 2013, 308 patients underwent cardiac surgery (Group B). In this group, we applied a more restricted antibiotic protocol, considering the resistance patterns and the results of microbiological tests of group A. We also evaluated the results of MIC susceptibility testing of five antibiotics: oxacillin, linezolide, daptomycin, teicoplanin and vancomycin. In the new protocol the first vancomycin dose was given 1 hour before sternal incision followed by three additional doses (48 hours duration).

Results

In group A, 26 patients (11.45%) developed sternal wound infection. Twenty out of 26 patients had staphylococcal infections characterized by high prevalence of oxacillin resistance while six patients had Gram-negative infections. In the vancomycin prophylaxis group (group B) we observed a significant reduction in the incidence of sternal wound infection rate (P < 0.01). Among 308 patients, six patients (1.94%) developed sternal wound infections, two of them caused by coagulase-negative oxacillin-resistant staphylococci while in four patients Gram-negative microorganisms were cultured. Mortality in infected patients was 0% in both groups.

Conclusion

Appropriate antibiotic prophylaxis in cardiac surgery patients is of paramount importance in preventing sternal wound infections, resulting in dramatic reduction of postoperative morbidity and in significant economic benefits.