title: Penicillin sensitive nutritionally variant streptococcal endocarditis: relapse after penicillin therapy.
abstract: Studies to date have indicated that nutritionally-variant streptococci (NVS) causing bacterial endocarditis are frequently inhibited but not killed by low concentrations of penicillin. We report a patient with endocarditis due to a NVS strain which was killed in vitro by penicillin at a concentration of 0.09 microgram/ml. Despite therapy with intravenous penicillin for four weeks, the infection relapsed and was then cured by combined penicillin-gentamicin in therapy. In vitro studies demonstrated a synergistic effect of these two antibiotics. This experience suggests that combination therapy with penicillin and an aminoglycoside may be required for cure of all cases of nutritionally-variant streptococcal endocarditis regardless of in vitro susceptibility to penicillin.
mesh_terms: D000368:Aged; D004357:Drug Synergism; D004697:Endocarditis, Bacterial / Q000188:drug therapy*; D005839:Gentamicins / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D010403:Penicillin Resistance; D010406:Penicillins / Q000494:pharmacology / Q000627:therapeutic use*; D012008:Recurrence; D013290:Streptococcal Infections / Q000188:drug therapy*; D013291:Streptococcus / Q000187:drug effects
chemical_list: D005839:Gentamicins; D010406:Penicillins