TABLE 1 

MICs of different antibiotics and ampC expression levels for strains PAO1 and PA14 and mutants derived from these two strains

StrainMIC (µg/ml)aAvg level of ampC expression ± SDb
CAZFEPPIP-TZATMIMPMERVANCOL
PAO111411.50.385120.751
PAΔD646461.515120.7563.3 ± 7.1
PAΔDDh2161296161.515120.7579.5 ± 12.2
PAΔDDh34832>256161.525120.75251.2 ± 51.9
PAΔDDh2Dh34832>256321.525120.751,225 ± 101
PAΔDDh2Dh3 + pUCPAD1.51.561.510.55120.752.9 ± 0.7
PAΔdacB321296161.50.55120.7553 ± 22.2
PAΔdacBΔD12864>25648225120.751,770 ± 401
PAΔAG11310.380.385120.75−1.1 ± 0.4
PAO1 + pUCPAC241696161.51.55120.751,925.5 ± 514
PAΔAG + pUCPAC241696161.51.55120.751,480 ± 359.1
PA140.750.53110.1255120.255.2 ± 2.9
PA14ΔD1.51.54310.195120.258.9 ± 1.5
PA14ΔDh20.750.53110.1255120.255.1 ± 1.2
PA14ΔDh30.750.53110.1255120.254.5 ± 2.2
PA14ΔDh2Dh310.53110.195120.254.7 ± 1.5
PA14ΔDDh210.7541.510.1255120.2512 ± 2.1
PA14ΔDDh31681281611.55120.254,561 ± 570
PA14ΔDDh2Dh3168>256241.51.55120.255,569 ± 928
PA14ΔDDh2Dh3 + pUCPAD21.56310.255120.25152.2 ± 77.1
PA14ΔdacB438410.195120.2536 ± 10.2
PA14ΔdacBΔD86961210.255120.25114.1 ± 42.1
  • a Abbreviations: CAZ, ceftazidime; FEP, cefepime; PIP-TZ, piperacillin-tazobactam; ATM, aztreonam; IMP, imipenem; MER, meropenem; VAN, vancomycin; COL, colistin.

  • b Relative amount of ampC mRNA compared to the amount expressed in strain PAO1.