Case presentation
A 51-year-old male with history of ischemic cardiomyopathy had an LVAD HeartMate III implanted in November 2019. He developed his first VAD-specific infection in April 2020, further classified as late-onset6. The patient’s driveline drainage culture was positive for MSSA and was started on oral doxycycline 100mg every 12 hours which was continued as suppressive therapy. September 2021, patient was admitted with worsening driveline infection (DLI). During this admission, he underwent incision and drainage with excisional debridement of infected subcutaneous tissue. MSSA with the same susceptibility patterns as prior wound culture was isolated and after several days of intravenous cefazolin, patient was transitioned to oral doxycycline 100mg and oral rifampin 300mg every 12 hours. Rifampin treatment was anticipated for 6 weeks, however patient was unable to tolerate due to gastrointestinal adverse effects and stopped therapy at 4 weeks. The patient was readmitted four months following surgical debridement, found to have MSSA on blood cultures. Susceptibilities remained similar, with an increase from <0.25 to 0.5 MIC reported for oxacillin. He was started on cefazolin for one day, and then transitioned to oxacillin 2g every 4 hours. Complicating care, patient was noted to have a small mass concerning for vegetation on his tricuspid valve and was pacemaker dependent. The patient remained clinically stable but with ongoing bacteremia despite 7 days of targeted therapy. Source control was hindered given patient was not a candidate for transplant, given his current smoking status and pacemaker dependency. Ultimately, the decision was made to add ertapenem 1g every 24 hours to 12g continuous infusion oxacillin for salvage therapy. Within 24 hours of starting combination therapy, patient had resolution of persistent bacteremia. He was kept on ertapenem 1g every 24 hours for 7 days total and transitioned to intravenous oxacillin 12g a day for 6 weeks. No adverse events were noted with the addition of ertapenem and remains without relapse for 3 months.