Penicillin and netilmicin in treatment of experimental enterococcal endocarditis.
Successful therapy of enterococcal endocarditis requires the use of a combination of penicillin plus an aminoglycoside. The effectiveness of penicillin (Pen), streptomycin (Str), and netilmicin (Net), a new aminoglycoside, alone and in combination, were studied in vitro and in the treatment of left-sided enterococcal endocarditis in rabbits. In vitro Pen+Str or Net resulted in a more rapid and more complete bactericidal effect than Pen, Str, or Net alone against a Str-susceptible strain of enterococcus (strain 1). Against a highly Str-resistant strain (strain 2), Pen+Net showed an advantage over Pen, Str, or Net alone, or Pen+Str. Endocarditis was produced in rabbits with strain 1 or 2, and treatment was initiated 24 h later. Rabbits were treated for 48 h or 5 days with procaine Pen, Pen+Str, or Pen+Net. With strain 1, numbers of enterococci in the vegetations decreased more rapidly with Pen+Str or Pen+Net treatment than with Pen, Str, or Net alone. With strain 2, Pen+Net showed a clear advantage over Pen, Str, Net, or Pen+Str. Net in combination with Pen showed synergistic in vitro activity and was more effective than Pen alone in the treatment of enterococcal endocarditis in rabbits caused by both Str-susceptible and Str-resistant strains.
D000818:Animals; D004359:Drug Therapy, Combination; D004697:Endocarditis, Bacterial / Q000188:drug therapy*; D004756:Enterobacteriaceae Infections / Q000188:drug therapy*; D013293:Enterococcus faecalis / Q000187:drug effects; D005260:Female; D009428:Netilmicin / Q000627:therapeutic use*; D010403:Penicillin Resistance; D010406:Penicillins / Q000627:therapeutic use*; D011817:Rabbits; D013290:Streptococcal Infections / Q000188:drug therapy; D013307:Streptomycin / Q000627:therapeutic use
D010406:Penicillins; D009428:Netilmicin; D013307:Streptomycin