In vitro activity of macrolides and lincosamides against oral streptococci: a therapeutic alternative in prophylaxis for infective endocarditis

Abstract

Susceptibility to macrolides and lincosamides was tested in a total of 446 strains of oral streptococci belonging to eleven species, all isolated from dental plaque and/or saliva in 1991. Minimum inhibitory concentrations (MIC) were determined by the double serial dilutions method in agar. Clindamycin was the most effective antibiotic against all species tested. The results of nearly all parameters (range, mean, MIC(50), MIC(90)) in all species showed erythromycin to be less effective than josamycin, making the latter antibiotic a possible alternative to erythromycin in prophylaxis for infective endocarditis caused by oral streptococci, not only in patients allergic to penicillin, but also in all patients with low-risk lesions, who will be treated with low-risk dental procedures. In these latter patients, antibiotic prophylaxis may be indicated if, after careful evaluation of the individual's situation, no other alternatives are available.