Streptococcus mitis endocarditis. Report of 17 cases.

Seventeen patients with Streptococcus mitis endocarditis were treated at a municipal hospital over a three-year period. Thirteen patients were intravenous drug addicts. Streptococcus mitis has a predilection for right-sided endocarditis in intravenous drug addicts and left-sided endocarditis in non-drug addicts. Streptococcus mitis is highly susceptible to therapy with penicillin G potassium (minimal inhibitory concentration less than or equal to 0.1 mg/L of penicillin in all of these 17 cases), and four to six weeks of therapy is safe and effective.