Open AccessIn Vitro Activity of Netilmicin, Gentamicin, and Amikacin
Author(s) -
Robert J. Kantor,
Carl W. Norden
Publication year - 1977
Publication title -
antimicrobial agents and chemotherapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.07
H-Index - 259
eISSN - 1070-6283
pISSN - 0066-4804
DOI - 10.1128/aac.11.1.126
Subject(s) - netilmicin , amikacin , microbiology and biotechnology , gentamicin , agar dilution , proteus mirabilis , providencia , biology , sisomicin , antibacterial agent , aminoglycoside , minimum inhibitory concentration , enterobacteriaceae , staphylococcus aureus , antibiotics , escherichia coli , bacteria , tobramycin , biochemistry , genetics , gene
The in vitro activity of netilmicin (Sch 20569), a new semisynthetic derivative of gentamicin, was compared with that of gentamicin and amikacin. One hundred and ninety-two clinical isolates ofEnterobacteriaceae, Pseudomonas aeruginosa , andStaphylococcus aureus were tested using both agar and broth dilution techniques. Netilmicin was comparable to gentamicin, with the following exceptions: (i) forSerratia marcescens andP. aeruginosa , gentamicin was more active than netilmicin; (ii) all strains ofEscherichia coli, Klebsiella, Enterobacter, Proteus mirabilis , andCitrobacter freundii , which were resistant to gentamicin, were susceptible to netilmicin; (iii) some strains ofS. marcescens , indole-positiveProteus , andProvidencia , which were resistant to gentamicin, were susceptible to netilmicin. Netilmicin was more active than amikacin for allEnterobacteriaceae andS. aureus and equal to amikacin in activity against gentamicin-susceptible strains ofP. aeruginosa . All strains ofP. aeruginosa , resistant to gentamicin, were also resistant to netilmicin but were susceptible to amikacin. Minimal inhibitory concentrations (MICs) obtained with broth and agar showed no significant differences except forP. mirabilis , where broth MICs were twofold greater than agar MICs, and forP. aeruginosa , where agar MICs were twofold higher than broth MICs. The minimal bactericidal concentration (MBC) was either identical to or within one twofold dilution of the MIC for the strains tested. A 100-fold increase in inoculum size produced less increase in MIC and MBC with netilmicin than with gentamicin or amikacin.