[In vitro effect of combinations of netilmicin and amikacin with fosfomycin and pefloxacin on 31 strains of heterogeneous methicillin- resistant Staphylococcus aureus].
The Minimal Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) of 31 strains of Staphylococcus aureus resistant to methicillin and gentamicin were determined towards aminoglycosides: netilmicin (N) and amikacin (A). The results of the study showed a large discordance between the technic using dilution in Mueller-Hinton broth and the technic using agar diffusion with antibiotic discs. The level of sensitivity appears to decrease by dilution. The problem of using these aminoglycosides in combination with other antibiotics as fosfomycin (F) and pefloxacin (P) was faced. In vitro, antibacterial activity of combinations [N-F], [N-P] and [A-F], [A-P], was studied by microtiter checkerboard method. The antibacterial effects of these combinations were evaluated by determination of Fractional Bactericidal Indices (FBC-indices). The combination netilmicin or amikacin with pefloxacin has an additive bactericidal effect in most cases, without discrimination between the different aminoglycosides (FBC #0.82). Netilmicin or amikacin in combination with fosfomycin are found to be additive or moderately synergistic (FBC #0.53). No occurrence of antagonism was observed.
David
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Laboratoire Central de Bactériologie, Virologie, Immunologie, CHR Robert Debré, Reims.
Chaste
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Saison
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Combremont
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AG
D000583:Amikacin / Q000008:administration & dosage; D004352:Drug Resistance, Microbial; D004357:Drug Synergism; D004359:Drug Therapy, Combination / Q000494:pharmacology*; D005578:Fosfomycin / Q000008:administration & dosage; D006801:Humans; D066298:In Vitro Techniques; D008712:Methicillin / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D009428:Netilmicin / Q000008:administration & dosage; D015366:Pefloxacin / Q000008:administration & dosage; D013203:Staphylococcal Infections / Q000188:drug therapy; D013211:Staphylococcus aureus / Q000187:drug effects*
D015366:Pefloxacin; D005578:Fosfomycin; D009428:Netilmicin; D000583:Amikacin; D008712:Methicillin
Activité in vitro des associations de la nétilmicine et de l'amikacine avec la fosfomycine et la péfloxacine sur trente et une souches de Staphylococcus aureus méticilline-résistantes hétérogènes.