Open wounds and rifampicin therapy are associated with rifampicin resistance among staphylococcal vascular graft/endograft infections

Yau Kei Stefan Leung; Bruno Ledergerber; Nadia Eberhard; Carlos A Mestres; Zoran Rancic; Alexander Zimmermann; Reinhard Zbinden; Silvio D Brugger; Annelies S Zinkernagel; Barbara Hasse; Vascular Graft Cohort Study

doi:10.1093/jacamr/dlab041

Open wounds and rifampicin therapy are associated with rifampicin resistance among staphylococcal vascular graft/endograft infections

JAC Antimicrob Resist. 2021 Mar 25;3(1):dlab041. doi: 10.1093/jacamr/dlab041. eCollection 2021 Mar.

Affiliations

¹ Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Raemistrasse 100, Zurich, Switzerland.
² Clinic for Cardiac Surgery, University Hospital Zurich, University of Zurich, Raemistrasse 100, Zurich, Switzerland.
³ Clinic for Vascular Surgery, University Hospital Zurich, University of Zurich, Raemistrasse 100, Zurich, Switzerland.
⁴ Institute of Medical Microbiology, University of Zurich, Gloriastrasse 28, Zurich, Switzerland.

Abstract

Background: Optimal timing for rifampicin combination therapy in patients with staphylococcal vascular graft/endograft infection (S-VGEI) is unknown. Experts recommend adding rifampicin after lowering bacterial load by surgery and wound closure.

Objectives: To assess predictors of rifampicin resistance among staphylococci isolated from patients in the Vascular Graft Infection Cohort Study.

Methods: We included prospective patients with S-VGEI diagnosis from 1 January 2002 to 30 June 2020. We retrospectively assessed determinants of rifampicin resistance using exact logistic regression and described survival with Kaplan-Meier curves.

Results: We analysed 513 Staphylococcus spp. among 143 predominantly male (82%) patients with a median age of 68 years (IQR 60-75). Thereof, 82 (57%) received a rifampicin combination therapy and 61 (43%) received an antimicrobial therapy without rifampicin. Among 82 patients with rifampicin, 26/26 patients with any rifampicin resistance had open wounds with a strong association of rifampicin resistance with rifampicin treatment while having open wounds (OR 37, 95% CI 6.1 to ∞). Among 75 patients with a rifampicin combination therapy and rifampicin-susceptible staphylococci at S-VGEI diagnosis, 12/12 patients with a secondary rifampicin-resistant isolate had an open wound (OR 14, 95% CI 2.1 to ∞).

Conclusions: Rifampicin should be started after wound closure due to increased risk of rifampicin resistance observed while having open wounds or second-look surgeries among patients with S-VGEI.