Post-surgical mediastinitis due to carbapenem-resistantEnterobacteriaceae: Clinical, epidemiological and survivalcharacteristics

ABSTRACT

Invasive infections due to carbapenem-resistant Enterobacteriaceae (CRE),including polymyxin-resistant(PR-CRE) strains, are being increasingly reported. However, there is a lack of clinical data for several life threatening infections. Here we describe a cohort of patients with post-surgical mediastinitis due to CRE,including PR-CRE. This study was a retrospective cohort design at a single cardiology centre. Patients with mediastinitis due to CRE were identified and were investigated for clinically relevant variables. Infecting isolates were studied using molecular techniques. Patients infected with polymyxin-susceptible CRE(PS-CRE) strains were compared with those infected with PR-CRE strains. In total, 33 patients with CRE mediastinitis were studied, including 15 patients (45%) with PR-CRE. The majority (61%) were previously colonised. All infecting isolates carriedblaKPC genes. Baseline characteristics of patients with PR-CRE mediastinitis were comparable with those with PS-CRE mediastinitis. Of the patients studied, 70% received atleast one agent considered active in vitro and most patients received at least three concomitant antibiotics. Carbapenem plus polymyxin B was the most common antibiotic combination (73%). Over 90% of patients underwent surgical debridement. Overall, in-hospital mortality was 33% and tended to be higherin patients infected with PR-CRE (17% vs. 53%; P = 0.06). In conclusion, mediastinitis due to CRE, includingPR-CRE, can become a significant challenge in centres with CRE and a high cardiac surgery volume. Despite complex antibiotic treatments and aggressive surgical procedures, these patients have a highmortality, particularly those infected with PR-CRE...