TABLE 2.
Viable bacterial counts after three dosing cycles with 1- or 2-g doses of cefepime, ceftazidime, aztreonam, ceftazidime-aztreonam, and cefepime-aztreonam
| Strain | Mean total log10 CFU/ml at 24 h (mean mutant log10 CFU/ml)a
|
||||||||
|---|---|---|---|---|---|---|---|---|---|
| Drug-free control | Cefepime (1 g) | Cefepime (2 g) | Ceftazidime (1 g) | Ceftazidime (2 g) | Aztreonam (1 g) | Aztreonam (2 g) | Ceftazidime + aztreonamb | Cefepime + aztreonamb | |
| P. aeruginosa 164 | 9.2 | 3.8 (0) | 3.9 (0) | 5.2 (0) | NDc | 5.0 (0) | ND | 4.5 (0) | 2.5 (0) |
| P. aeruginosa 164PD | 9.1 | 9.5 (8.3) | 6.2 (0) | 9.5 (5.6) | ND | 9.3 (5.9) | 5.5 (0) | 8.4 (7.3) | 3.1 (2.3) |
| P. aeruginosa 164FD | 8.9 | ND | 7.9 | ND | 9.0 | ND | 8.3 | 8.4 | 3.8 |
| P. aeruginosa 113M | 9.2 | 7.2 (0) | ND | 8.0 (0) | ND | 5.5 (0) | 4.9 (0) | 3.3 (0) | 3.5 (0) |
| P. aeruginosa 111M | 9.2 | 7.8 (0) | ND | 8.1 (0) | ND | 3.9 (0) | 3.5 (0) | 3.8 (0) | 2.8 (0) |
| P. aeruginosa GB57 | 9.0 | ND | 9.0 | ND | 9.7 | ND | 9.2 | 9.2 | 7.5 |
| P. aeruginosa GB66 | 9.0 | ND | 8.2 | ND | 9.4 | ND | 8.9 | 7.9 | 5.0 |
| P. aeruginosa GB3 | 9.0 | ND | 9.0 | ND | 9.5 | ND | 7.8 | 7.8 | 5.9 |
a
The number of mutants was measured by plating the samples used to determine total viable bacterial counts into agar containing antibiotic at a concentration fourfold above the MIC.
b
Simulated 1- or 2-g doses of aztreonam were dosed simultaneously with 1- or 2-g doses of either cefepime or ceftazidime.
c
ND, not done.