False synergy between vancomycin and beta-lactams against glycopeptide-intermediate Staphylococcus aureus (GISA) caused by inappropriate testing methods.
The combination of vancomycin and beta-lactams is often considered synergistic and has been recommended for the treatment of glycopeptide-intermediate Staphylococcus aureus (GISA) infections. In this study, the combination of vancomycin or teicoplanin with different beta-lactams was tested. When using NaCl 4% w/v, for better expression of heterogeneous resistance to beta-lactams, with a longer (48-h) incubation period and a higher (10(7) CFU/mL) inoculum, the association of vancomycin with beta-lactams was antagonistic. However, a synergistic effect was observed for teicoplanin under the same conditions.
Goldstein
F W
FW
Fondation Hospital Saint-Joseph, 185 rue Raymond Losserand, 75014 Paris, France. fgoldstein@hospital-saint-joseph.org
Atoui
R
R
Ben Ali
A
A
Nguyen
J C
JC
Ly
A
A
Kitzis
M D
MD
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004357:Drug Synergism; D005189:False Positive Reactions; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods; D013211:Staphylococcus aureus / Q000187:drug effects*; D017334:Teicoplanin / Q000494:pharmacology*; D014640:Vancomycin / Q000494:pharmacology*; D047090:beta-Lactams / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D047090:beta-Lactams; D017334:Teicoplanin; D014640:Vancomycin