TABLE 3.

Drug susceptibilities of the various mutants constructed in strain PAO1

Bacterial strainInactivated gene(s)MIC (μg/ml)a
GENAMKTOBNETKANCIPFEP
PAO1Wild type140.54640.254
FE10nuoG28182560.254
FE49galU28181280.254
FE53mexZ4818128116
FE57rplY28-16182560.54
FE57rplY complemented with pARAL25b140.25NDND0.25ND
FE10UnuoG, galU48282560.254
FE53UmexZ, galU8162162560.5-116
FE57UrplY, galU8162162560.54-8
FE53GmexZ, nuoG816216256116
FE57GrplY, nuoG8322165120.54
FE57ZrplY, mexZ816216256116
FE53GUmexZ, nuoG, galUND32464512116
FE57GUrplY, nuoG, galUND324645120.58
FE57UZrplY, galU, mexZND32464512116
FE57GZrplY, nuoG, mexZND3241281,024116
FE57GUZrplY, nuoG, galU, mexZND6482561,024116
KJ7106PA54710.12510.25NDND0.254
FE60mexXY0.12510.25NDND0.254
FE63rplY, PA54710.2520.5NDND0.252
FE64rplY, mexXY0.2520.5NDND0.252
  • a Results of two independent determinations are given. The MICs in boldface correspond to additive (2-fold increase) or multiplicative (>2-fold increase) effects of combined mutations on resistance. GEN, gentamicin; AMK, amikacin; TOB, tobramycin; NET, netilmicin; KAN, kanamycin; CIP, ciprofloxacin; FEP, cefepime. ND, not determined.

  • b Gene rplY cloned on arabinose-inducible plasmid pARA6. Transformants were grown in the presence of 150 μg per ml ticarcillin for plasmid maintenance and 0.2% arabinose. Control strain FE57(pARA6) cultivated under the same conditions exhibited resistance levels similar to those of FE57 in MHA.