OBJECTIVES: The study aimed to review a multicentre experience of patients undergoing surgical intervention for infective endocarditis caused by Cutibacterium acnes and to analyse the diagnostic challenges and operative results.

METHODS: We retrospectively reviewed 8812 patients undergoing cardiac surgery for endocarditis at 12 cardiac surgical departments across Germany. The overall population was divided based on the type of endocarditis (i.e. native and prosthetic valve endocarditis). Primary outcomes were in-hospital mortality, 1- and 5-year survival.

RESULTS: Cutibacterium acnes caused endocarditis in 269 patients (3.1%). Median age was 65 years (54-72 years) and 237 (88.1%) were male. We observed significantly higher rates of native valve endocarditis in patients aged 21-40, whereas prosthetic valve endocarditis was more frequent in all other age groups (P < 0.001). The median EuroSCORE II of the cohort was 10.7 (5.0-29.6), with it being significantly higher in the prosthetic valve endocarditis group (P < 0.001). Blood culture-negative infective endocarditis was initially reported in 54.3% of the patients. The in-hospital mortality was comparable between the groups (P = 0.340). Survival at 1 and 5 years was significantly higher in the native valve endocarditis group (P < 0.001).

CONCLUSIONS: Cutibacterium acnes causes native valve endocarditis, especially in younger patients. The incidence of endocarditis caused by C.acnes is alarming and is at par with well-known endocarditis pathogens such as the HACEK group. The pathogen has a low virulence and presents with a rather indolent course. The diagnosis of C.acnes endocarditis is challenging and requires a multimodal specialized approach. Surgical treatment is associated with acceptable outcomes.