Infective endocarditis by Actinomyces species: a systematic review

Actinomycosis, is a slowly progressive infection that may mimic malignancy due to the invasiveness of tissues and the ability to form sinus tracts. Infective Endocarditis (IE) is a rare disease with significant morbidity and mortality. Interestingly, even though there are scarce data of IE by Actinomyces spp. in the literature, a review adequately summarizing all available evidence on the topic in a systematic way is lacking. The aim of this study was to systematically review all cases of IE by Actinomyces spp. in the literature and describe the epidemiology, microbiology, clinical characteristics, treatment and outcomes of this infection. A systematic review of PubMed, Scopus and Cochrane library (through 19 August 2021) for studies providing epidemiological, clinical, microbiological as well as treatment data and outcomes of IE by Actinomyces spp. was performed. A total of 31 studies providing data for 31 patients were included. A prosthetic valve was present in 12.9%, while the most common microorganism was A. meyeri. Aortic valve was the most commonly infected intracardiac site, followed by the mitral valve. Diagnosis was most commonly performed with transesophageal echocardiography, while the diagnosis was made at autopsy in 16.1%. Penicillin, cephalosporins and aminopenicillins were the most commonly used antimicrobials. Clinical cure was noted in 80.6%, while mortality was 19.4%. Development of heart failure was associated with mortality by IE. This systematic review thoroughly describes IE by Actinomyces and provides information on epidemiology, clinical presentation, treatment and outcomes.