Epidemiology, Clinical Features, and Outcome of Infective Endocarditis due to Abiotrophia Species and Granulicatella Species: Report of 76 Cases, 2000-2015.

Background: Infective endocarditis (IE) caused by Abiotrophia (ABI) and Granulicatella (GRA) species is poorly studied. This work aims to describe and compare the main features of ABI and GRA IE. Methods: We performed a retrospective study of 12 IE institutional cases of GRA or ABI and of 64 cases published in the literature (overall, 38 ABI and 38 GRA IE cases). Results: ABI/GRA IE represented 1.51% of IE cases in our institution between 2000 and 2015, compared to 0.88% of HACEK (Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella)-related IE and 16.62% of Viridans group streptococci (VGS) IE. Institutional ABI/GRA IE case characteristics were comparable to that of VGS, but periannular complications were more frequent (P = .008). Congenital heart disease was reported in 4 (10.5%) ABI and in 11 (28.9%) GRA cases (P = .04). Mitral valve was more frequently involved in ABI than in GRA (P < .001). Patient sex, prosthetic IE, aortic involvement, penicillin susceptibility, and surgical treatment were comparable between the genera. New-onset heart failure was the most frequent complication without genera differences (P = .21). Five (13.2%) ABI patients and 2 (5.3%) GRA patients died (P = .23). Factors associated with higher mortality were age (P = .02) and new-onset heart failure (P = .02). The genus (GRA vs ABI) was not associated with higher mortality (P = .23). Conclusions: GRA/ABI IE was more prevalent than HACEK IE and approximately one-tenth as prevalent as VGS; periannular complications were more frequent. GRA and ABI genera IE presented similar clinical features and outcomes. Overall mortality was low, and related to age and development of heart failure.