Infective endocarditis caused by penicillin-resistant viridans group streptococci: a series of nine cases from a Spanish cohort

• Published in: Journal of antimicrobial chemotherapy
• Main Authors: Escrihuela-Vidal, Francesc, Fernández-Hidalgo, Núria, Muñoz, Patricia, Villamarín, Miguel, Jiménez García, Nicolás, Escudero, Encarnación Moral, Martínez Marcos, Francisco Javier, Cuervo, Guillermo, Boix-Palop, Lucía, Berbel, Dámaris, Carratalà, Jordi, Miró, Jose M
• Format: Journal Article
• Language: English
• Published: England 01.10.2024
• ISSN: 0305-7453; 1460-2091; 1460-2091
• DOI: 10.1093/jac/dkae345

Infective endocarditis (IE) caused by viridans and gallolyticus group streptococci (VGS-GGS) resistant to penicillin (PEN-R; minimum inhibitory concentration ≥4 mg/L) is rare but poses therapeutic challenges. To describe the characteristics of patients with IE caused by PEN-R VGS-GGS, focusing on antimicrobial management. Retrospective analysis of a prospective cohort of definite IE caused by PEN-R VGS-GGS between 2008 and 2023 in 40 Spanish hospitals. We describe clinical characteristics, management and outcome of the cases, and compare them to IE caused by VGS-GGS with susceptibility or susceptibility with increased exposure to penicillin (PEN-I). We identified nine cases of PEN-R VGS-GGS IE in a cohort of 1563 streptococcal IE (0.58%). All isolates belonged to S. mitis group. Three cases died during hospitalization and no relapse occurred at 3 months of follow-up. Compared to cases with susceptibility or PEN-I, PEN-R showed a higher rate of mitral location (78% versus 51%), surgical indication (67% versus 51%), and in-hospital mortality (33% versus 12%). Most cases (86%) showed resistance to third-generation cephalosporins. The preferred antibiotic regimen was beta-lactam-based: ceftriaxone plus gentamicin, penicillin plus gentamicin, ceftriaxone plus levofloxacin, and ceftaroline plus daptomycin. Two cases received a combination of vancomycin plus gentamicin. Levofloxacin was used in two cases in combination with ceftriaxone or daptomycin. All patients that received cardiac surgery were cured at the end of follow-up. IE caused by PEN-R VGS-GGS was rare and only affected mitis group streptococci. Antibiotic combination including a beta-lactam seems to be effective in its management.