Viridans streptococcal (Streptococcus mitis) biosynthetic aortic prosthetic valve endocarditis (PVE) complicated by complete heart block and paravalvular abscess

Abstract

Prosthetic valve endocarditis (PVE) may be classified clinically as early (<60 days) or late (>60 days) post-valve replacement PVE. The pathogens of early versus late PVE differ in type and virulence. Early PVE pathogens are virulent, for example, Pseudomonas aeruginosa and Staphylococcus aureus. Late PVE pathogens resemble those of subacute bacterial endocarditis and are due to relatively avirulent and noninvasive organisms, for example, viridans streptococci. Viridans streptococci vary in their invasiveness and abscess potential. Myocardial abscess and complete heart block are rare complications of late PVE due to viridans streptococci. We present an unusual case of Streptococcus mitis late aortic PVE complicated by aortic root abscess, myocardial abscess, and complete heart block.