Impact of Intermediate Susceptibility to Penicillin on Antimicrobial Treatment and Outcomes of Endocarditis Caused by Viridans and Gallolyticus Group Streptococci.

This article focuses on the clinical characteristics and treatment outcomes of infective endocarditis caused by viridans and gallolyticus group streptococci (VGS-GGS) with intermediate susceptibility to penicillin (PEN-I). Analyzing 914 cases from 40 Spanish hospitals between 2008 and 2018, the study compares combination therapy with a beta-lactam plus an aminoglycoside (C-BA) against third-generation cephalosporin monotherapy. Results indicate that PEN-I VGS-GGS endocarditis had similar in-hospital mortality and relapse rates compared to penicillin-susceptible cases, and cephalosporin monotherapy was not associated with increased in-hospital mortality, suggesting it as a viable treatment option to avoid aminoglycoside-related nephrotoxicity. Factors such as heart failure, central nervous system emboli, and intracardiac abscess were independently linked to mortality, while monotherapy did not increase in-hospital mortality risk. These findings support reconsideration of current guidelines favoring aminoglycoside use in PEN-I VGS-GGS endocarditis to reduce renal toxicity without compromising patient outcomes.