Activity of newer aminoglycosides and carbenicillin, alone and in combination, against gentamicin-resistant Pseudomonas aeruginosa.
The in vitro activity of the aminoglycoside antibiotics tobramycin, sisomicin, amikacin, gentamicin, and netilmicin (SCH 20569) were compared against 26 gentamicin-resistant isolates of Pseudomonas aeruginosa cultured from hospitalized children. Tobramycin had the greatest activity on a weight basis, followed by sisomicin, gentamicin, amikacin, and netilmicin. All isolates were resistant to achievable concentrations of netilmicin and gentamicin, but 23% were inhibited by achievable concentrations of tobramycin, 8% by amikacin, and 4% by sisomicin. The combinations carbenicillin/tobramycin, carbenicillin/sisomicin, and carbenicillin/amikacin were synergistic for 92% of strains; antagonism was not encountered. These in vitro results suggest that tobramycin, sisomicin, or amikacin in combination with carbenicillin would be the safest initial regimen in the therapy of gentamicin-resistant Pseudomonas infections pending susceptibility studies.
D000583:Amikacin / Q000494:pharmacology; D000617:Aminoglycosides / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002228:Carbenicillin / Q000494:pharmacology*; D005839:Gentamicins / Q000494:pharmacology; D010403:Penicillin Resistance; D011550:Pseudomonas aeruginosa / Q000187:drug effects*; D012853:Sisomicin / Q000031:analogs & derivatives / Q000494:pharmacology; D014031:Tobramycin / Q000494:pharmacology
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D005839:Gentamicins; D000583:Amikacin; D002228:Carbenicillin; D014031:Tobramycin; D012853:Sisomicin