A 67-year-old man with a prosthetic heart valve presents with fever (38.9°C), new systolic murmur, and malaise 6 months post-replacement. Vital signs show HR 102/min, BP 118/76 mmHg, RR 18/min, SpO2 98% on room air. Blood cultures grow gram-positive cocci in chains that are catalase-negative and alpha-hemolytic. Echocardiography reveals vegetation on the prosthetic valve. He denies recent dental procedures or IV drug use. Which organism is most likely responsible?
- A)Staphylococcus epidermidis
- B)Enterococcus faecalis
- C)Streptococcus agalactiae
- D)Staphylococcus aureus
- E)Viridans group StreptococcusGABARITO
Explicação
Viridans streptococci cause late prosthetic valve endocarditis (>12 months post-op) via hematogenous seeding from dental procedures or poor oral hygiene. They are alpha-hemolytic, catalase-negative, and form chains—distinguishing them from staphylococci. Ver explicação completa e trilha adaptativa →