Synergy between penicillin and gentamicin against enterococci.
The role of active uptake in aminoglycoside activity against penicillin-treated enterococci was studied by viable counts and ATP determinations. Penicillin and gentamicin gave synergistic bactericidal and post-antibiotic effects (PAEs) which were partially reduced by sodium azide, an electron transport inhibitor, and totally blocked in the presence of both sodium azide and EDTA, which chelates divalent cations. EDTA and gentamicin showed marked synergy in both 'killing curve' and PAE experiments. This synergy was completely inhibited by sodium azide. The data indicate that the activity of gentamicin against enterococci that have been damaged by penicillin or EDTA is energy-dependent. This is consistent with present theories of gentamicin uptake via transportation drive by a protonmotive force.
Winstanley
T G
TG
Department of Bacteriology, Royal Hallamshire Hospital, Sheffield, UK.
Hastings
J G
JG
D000255:Adenosine Triphosphate / Q000378:metabolism; D001386:Azides / Q000494:pharmacology; D004357:Drug Synergism; D004492:Edetic Acid / Q000494:pharmacology; D005839:Gentamicins / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D010406:Penicillins / Q000494:pharmacology*; D019810:Sodium Azide; D013291:Streptococcus / Q000187:drug effects* / Q000378:metabolism
D001386:Azides; D005839:Gentamicins; D010406:Penicillins; D000255:Adenosine Triphosphate; D019810:Sodium Azide; D004492:Edetic Acid