Streptococcus sanguinis Endocarditis in a Patient Who Received Clindamycin for Dental Prophylaxis

Abstract

Antibiotic prophylaxis has been recommended to prevent infective endocarditis in patients with valvular heart disease undergoing dental procedure. Erythromycin and clindamycin have been recommended as alternative agents in those who are allergic to penicillin. We report a penicillin-allergic patient who developed infective endocarditis despite clindamycin prophylaxis. Viridans-group Streptococcus that was later identified as Streptococcus sanguinis resistant to clindamycin was isolated from her blood. Initial therapy with clindamycin did not improve her symptoms. Her symptoms responded to linezolid therapy. She underwent mitral valve replacement because of deteriorating cardiac function. Postoperatively, she was treated successfully with linezolid and levofloxacin intravenously for 4 weeks. She remained well on her 30-month follow-up. Viridans-group Streptococcus, as a group, has been shown to be increasingly resistant to various antimicrobial agents including clindamycin and erythromycin. Although the percentage of resistant viridans-group Streptococcus strains is still low in most areas, local resistance should be monitored. If this trend should continue, the value of these antibiotics as prophylactic agent should be reevaluated.