Apparent failure of endocarditis prophylaxis caused by penicillin-resistant Streptococcus mitis.
Antibiotic resistance among viridans streptococci has increased with Streptococcus mitis being more resistant than other viridans species. In a case presented in this report, it is possible that antibiotic resistance contributed to an apparent failure of endocarditis prophylaxis. The patient had undergone periodontal surgery on 2 separate occasions and in both instances was administered 2 g of amoxicillin orally 1 hour before each procedure. He subsequently developed a subacute illness and had multiple blood cultures drawn that grew S. mitis with a minimum inhibitory concentration of 1.0 microg/mL for penicillin. Transesophageal echocardiogram provided further evidence of infective endocarditis with vegetations seen on the anterior leaflet of the mitral valve. Combination therapy with high-dose intravenous aqueous crystalline penicillin G and gentamicin sulfate for 4 weeks was curative. Clindamycin, rather than amoxicillin, has since been used as dental prophylaxis for subsequent procedures.
Hall
Glen E
GE
University of Tennessee Medical Center at Knoxville, Graduate School of Medicine, Department of Medicine, 37920-6999, USA.
Baddour
Larry M
LM
D000368:Aged; D000658:Amoxicillin / Q000008:administration & dosage*; D019072:Antibiotic Prophylaxis; D002981:Clindamycin / Q000008:administration & dosage; D024881:Drug Resistance, Bacterial; D004696:Endocarditis / Q000209:etiology / Q000382:microbiology* / Q000517:prevention & control; D006801:Humans; D008297:Male; D019647:Oral Surgical Procedures / Q000009:adverse effects; D010406:Penicillins / Q000008:administration & dosage*; D010510:Periodontal Diseases / Q000601:surgery; D013290:Streptococcal Infections / Q000209:etiology / Q000382:microbiology* / Q000517:prevention & control; D013291:Streptococcus / Q000187:drug effects*; D017211:Treatment Failure
D010406:Penicillins; D002981:Clindamycin; D000658:Amoxicillin