Table 1.
Impact of rifampicin on AG susceptibility of CF lung isolates of P. aeruginosaa
| Strainb | MIC (mg/L)c |
|||||||
|---|---|---|---|---|---|---|---|---|
| TOB |
AMK |
GEN |
NEO |
|||||
| −RIF | +RIFd | −RIF | +RIF | −RIF | +RIF | −RIF | +RIF | |
| K3518 | 32 | 8 (4) | 128 | 64 (2) | 256 | 64 (4) | 512 | 256 (2) |
| K3519 | 32 | 2 (16) | 128 | 8 (16) | 128 | 4 (32) | 256 | 64 (4) |
| K3520 | 16 | 8 (2) | 32 | 64 (0.5) | 64 | 64 (1) | 256 | 64 (4) |
| K3522 | 16 | 4 (4) | 32 | 16 (2) | 32 | 8 (4) | 1024 | 8 (128) |
| K3524 | 128 | 16 (8) | 512 | 256 (2) | 512 | 128 (4) | 1024 | 64 (16) |
| K3525 | 16 | 16 (1) | 1 | 2 (0.5) | 64 | 64 (1) | 32 | 16 (2) |
| K3526 | 1 | 2 (0.5) | 8 | 8 (1) | 8 | 8 (1) | 512 | 64 (8) |
| K3527 | 4 | 2 (2) | 64 | 8 (8) | 64 | 16 (4) | 512 | 64 (8) |
| K3528 | 4 | 1 (4) | 16 | 4 (4) | 16 | 2 (8) | 256 | 16 (16) |
| K3529 | 32 | 4 (8) | 4 | 4 (1) | 512 | 32 (16) | 32 | 1 (32) |
| K3530 | 16 | 16 (1) | 64 | 64 (1) | 64 | 64 (1) | 1024 | 16 (64) |
| K3531 | 32 | 8 (4) | 64 | 32 (2) | 128 | 32 (4) | 1024 | 128 (8) |
| K3532 | 16 | 16 (1) | 32 | 32 (1) | 16 | 32 (0.5) | 256 | 64 (4) |
| K3533 | 16 | 16 (1) | 128 | 128 (1) | 64 | 64 (1) | 1024 | 8 (128) |
| K3534 | 4 | 4 (1) | 32 | 8 (4) | 16 | 8 (2) | 512 | 8 (64) |
| K3535 | 16 | 16 (1) | 64 | 32 (2) | 128 | 32 (4) | 128 | 32 (4) |
| K3536 | 32 | 32 (1) | 256 | 256 (1) | 128 | 64 (2) | 1024 | 64 (16) |
| K3537 | 16 | 8 (2) | 32 | 16 (2) | 64 | 32 (2) | 512 | 64 (8) |
| K3538 | 64 | 8 (8) | 512 | 128 (4) | 512 | 64 (8) | 512 | 4 (128) |
| K3539 | 16 | 8 (2) | 128 | 32 (4) | 256 | 64 (4) | 2048 | 128 (16) |
| K3540 | 8 | 8 (1) | 64 | 64 (1) | 64 | 32 (2) | 1024 | 16 (64) |
| K3641 | 32 | 16 (2) | 32 | 32 (1) | 64 | 64 (1) | 128 | 128 (1) |
| K3642 | 64 | 16 (4) | 256 | 64 (4) | 128 | 32 (4) | 256 | 128 (2) |
| K3645 | 16 | 4 (4) | 64 | 16 (4) | 64 | 16 (4) | 256 | 2 (128) |
| K3647 | 16 | 8 (2) | 64 | 16 (4) | 64 | 32 (2) | 32 | 8 (4) |
| K3649 | 16 | 8 (2) | 64 | 32 (2) | 64 | 8 (8) | 512 | 32 (16) |
| K3651 | 16 | 8 (2) | 64 | 64 (1) | 64 | 32 (2) | 128 | 64 (2) |
| K3653 | 32 | 8 (4) | 128 | 32 (4) | 64 | 32 (2) | 256 | 64 (4) |
| K3656 | 64 | 32 (2) | 128 | 64 (2) | 128 | 64 (2) | 512 | 128 (4) |
| K3657 | 64 | 32 (2) | 256 | 64 (4) | 256 | 64 (4) | 512 | 256 (2) |
| K3659 | 128 | 32 (4) | 512 | 64 (8) | 256 | 32 (8) | 512 | 64 (8) |
| K3660 | 128 | 64 (2) | 512 | 256 (2) | 256 | 256 (1) | 512 | 256 (2) |
| K3665 | 16 | 4 (4) | 128 | 32 (4) | 128 | 16 (8) | 1024 | 8 (128) |
| K3667 | 16 | 4 (4) | 64 | 32 (2) | 64 | 64 (1) | 512 | 32 (16) |
| K3669 | 32 | 8 (4) | 128 | 64 (2) | 128 | 64 (2) | 256 | 8 (32) |
| K3673 | 512 | 256 (2) | 4096 | 512 (8) | ≥4096 | 256 (≥16) | 512 | 512 (1) |
| K3675 | 64 | 16 (4) | 256 | 128 (2) | 256 | 64 (4) | 2048 | 256 (8) |
| K3677 | 8 | 4 (2) | 32 | 8 (4) | 32 | 16 (2) | 256 | 16 (16) |
| K3679 | 32 | 4 (8) | 128 | 16 (8) | 128 | 16 (8) | 512 | 8 (64) |
| K3681 | 128 | 8 (16) | 256 | 16 (16) | 256 | 16 (16) | 512 | 4 (128) |
| K3683 | 128 | 16 (8) | 256 | 32 (8) | 256 | 32 (8) | 1024 | 128 (8) |
| K3685 | 1024 | 128 (8) | 1024 | 128 (8) | 2048 | 256 (8) | 512 | 256 (2) |
| K3687 | 128 | 8 (16) | 512 | 32 (16) | 512 | 16 (32) | 1024 | 128 (8) |
| K3689 | 16 | 4 (4) | 128 | 16 (8) | 16 | 8 (2) | 256 | 16 (16) |
| K3691 | 16 | 8 (2) | 128 | 32 (4) | 64 | 32 (2) | 256 | 64 (4) |
TOB, tobramycin; AMK, amikacin; GEN, gentamicin; NEO, neomycin; RIF, rifampicin.
Susceptibility of P. aeruginosa CF isolates to the indicated AGs was assessed in the absence (−) and presence (+) of rifampicin at ½ MIC.
Strains where rifampicin enhanced susceptibility to all tested AGs ≥4-fold are underlined. Strains where rifampicin enhanced susceptibility to all AGs except neomycin ≥4-fold are italicized.
Fold change in MIC of the indicated AG in the presence versus absence of rifampicin is indicated in parentheses. MIC values ≥4-fold lower in the presence of rifampicin are in bold.
Rifampicin was included in AG susceptibility assays at 2 mg/L (K3526), 4 mg/L (K3528, K3532, K3536, K3641, K3656, K3667), 8 mg/L (K3518, K3519, K3522, K3525, K3529, K3530, K3531, K3533, K3534, K3535, K3537, K3538, K3539, K3540, K3651, K3653, K3657, K3660, K3669, K3675, K3677, K3679, K3685, K3687, K3691) or 16 mg/L (K3520, K3524, K3527, K3642, K3645, K3647, K3649, K3659, K3665, K3673, K3681, K3683, K3689).