Vancomycin wound penetration in open-heart surgery patients receiving negative pressure wound therapy for deep sternal wound infection

Introduction It is hypothesized that systemically administered antibiotics penetrate wound sites more effectively during negative pressure wound therapy (NPWT). However, there is a lack of clinical data from patients who receive NPWT for deep sternal wound infection (DSWI) after open-heart surgery. Here, we evaluated vancomycin penetration into exudate in this patient group.Patients and methods For this prospective observational study, we enrolled 10 consecutive patients treated with NPWT for post-sternotomy DSWI. On the first sampling day, serum and exudate samples were synchronously collected at 0 (pre-dose), 0.5, 1, 2, 3 and 6 h after vancomycin administration. On the following three consecutive days, additional samples were collected, only before vancomycin administration.Results The ratio of average vancomycin concentration in wound exudate to in serum was higher for free (unbound) (1.51 ± 0.53) than for total (bound + unbound) (0.91 ± 0.29) concentration (p = 0.049). The percentage of free vancomycin was higher in wound exudate than serum (0.79 ± 0.19 vs. 0.46 ± 0.16; p = 0.04). Good vancomycin wound penetration was maintained on the following three days (vancomycin trough exudate-to-serum concentration ratio > 1). The total hospital stay was significantly longer in patients with DSWI (46 ± 11.6 days) versus without DSWI (14 ± 11.7 days) (p < 0.001). There was no in-hospital or 90-day mortality. Two patients experienced late DSWI recurrence. All-cause mortality was 4.8% during a median follow-up of 2.5 years.Conclusion Vancomycin effectively penetrates wound exudate in patients receiving NPWT for DSWI after open-heart surgery.The protocol for this study was registered at ClinicalTrials.gov on July 16, 2024 (NCT06506032).