Antimicrobial susceptibility of gentamicin-resistant Pseudomonas aeruginosa.

The susceptibility of 41 strains of gentamicin-resistant Pseudomonas aeruginosa to tobramycin, sisomicin, netilmicin, amikacin, and carbenicillin was determined. Amikacin and carbenicillin exhibited the greatest activity against these strains and especially against those with a high level of resistance to gentamicin. Netilmicin exhibited little activity, whereas tobramycin and sisomicin were active against approximately two-thirds of the strains. Cross-resistance to tobramycin, sisomicin, and netilmicin was frequent.