Cutibacterium Acnes Infective Endocarditis—An Emerging Pathogen

In this multicenter study, the authors aimed to review patients undergoing surgical intervention for infective endocarditis caused by Cutibacterium acnes and analyze the diagnostic challenges and operative results. A total of 8,812 patients undergoing cardiac surgery for infective endocarditis at 12 cardiac surgical departments across Germany were included and retrospectively analyzed. Primary outcomes were in-hospital mortality, one- and five-year survival. The overall population was divided based on the type of endocarditis (i.e., native and prosthetic valve endocarditis) for comparison. 

Cutibacterium acnes caused endocarditis in 269 patients (3.1 percent). The median age was 65 years (range, 54-72 years), and 237 (88.1 percent) were male. Native valve infective endocarditis was more common in patients aged 21-40 years, whereas prosthetic valve endocarditis was more common in all other age groups (p < 0.001). Blood culture-negative infective endocarditis was initially reported in 54.3 percent of the patients. The overall in-hospital mortality was 13 percent, with no statistically significant difference between patients with native valve (9.8 percent) and prosthetic valve (14.7 percent) infective endocarditis (p = 0.340). Survival at one year (97 percent versus 76 percent) and five years (87 percent versus 69 percent) was significantly higher in the native valve infective endocarditis group (p<0.001). 

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