Table 2.
Antibacterial effect of each simulated dosing regimen of the 3 antibiotics against ESBL-producing bacteria and Escherichia coli ATCC25922
| Dosage regimen | MKD (Log10 CFU/mL) | ΔlogN24 (Log10 CFU/mL) | RT (h) | T90% (h) | T99% (h) | T99.9% (h) | IE (Log10 CFU/mL h−1) | |
|---|---|---|---|---|---|---|---|---|
| 25922 | MOX (1g qd) | −4.4 | −0.9 | >24 | 23.1 | 19.3 | 10.0 | 127.6 |
| MOX (1g q12h) | −4.4 | −1.3 | >24 | >23.5 | 20.7 | 16.1 | 134.8 | |
| MOX (1g q8h) | −4.7 | −3.5 | >24 | >23.5 | >23.0 | >22.5 | 155.8 | |
| MOX (2g qd) | −4.7 | −1.8 | >24 | >23.6 | 21.5 | 17.2 | 145.7 | |
| MOX (2g q12h) | −4.8 | −3.2 | >24 | >23.5 | >23.0 | >22.5 | 155.4 | |
| MOX (2g q8h) | −4.6 | −3.3 | >24 | >23.5 | 23.1 | >22.5 | 158.1 | |
| CTX (2g qd) | −4.6 | −2.2 | >24 | >23.6 | >23.2 | 18.2 | 140.8 | |
| CTX (2g q8h) | −4.8 | −3.2 | >24 | >23.6 | >23.2 | >22.7 | 156.6 | |
| CFZ/SBT (2g qd) | −4.6 | −1.5 | >24 | >23.5 | 18.7 | 10.0 | 128.0 | |
| CFZ/SBT (2g q8h) | −4.7 | −3 | >24 | >23.5 | >22.9 | >22.1 | 151.5 | |
| 3376 | MOX (1g qd) | −4.2 | −0.2 | >24 | 21.1 | 17.5 | 8.5 | 118.9 |
| MOX (1g q12h) | −4.7 | −1.9 | >24 | >23.5 | 22.1 | 16.7 | 138.7 | |
| MOX (1g q8h) | −4.8 | −1.9 | >24 | >23.4 | 19.7 | 17.3 | 139.2 | |
| MOX (2g qd) | −4.6 | −0.8 | >24 | 23.0 | 19.0 | 10.6 | 127.7 | |
| MOX (2g q12h) | −4.6 | −2.1 | >24 | >23.4 | >22.8 | 16.6 | 142.4 | |
| MOX (2g q8h) | −4.8 | −2.9 | >24 | >23.5 | >22.9 | 20.6 | 148.2 | |
| CTX (2g qd) | −1.4 | 3.0 | 3.2 | 1.6 | NA | NA | 45.0 | |
| CFZ/SBT (2g qd) | −2.7 | 3.1 | 8.0 | 5.1 | 2.4 | NA | 39.4 | |
| CFZ/SBT (2g q8h) | −3.2 | 3.0 | 12.6 | 4.9 | 3.3 | 1.1 | 62.0 | |
| 2689 | MOX (1g qd) | −3.9 | −0.5 | >24 | 20.3 | 14.0 | 7.3 | 116.8 |
| MOX (1g q12h) | −5.1 | −1.9 | >24 | >23.3 | 21.0 | 6.3 | 143.2 | |
| MOX (1g q8h) | −4.7 | −2 | >24 | >23.3 | >22.5 | 17.9 | 147.6 | |
| MOX (2g qd) | −4.5 | −1.5 | >24 | >23.3 | 18.1 | 13.2 | 135.8 | |
| MOX (2g q12h) | −4.7 | −2.5 | >24 | >23.3 | >22.6 | 19.5 | 153.0 | |
| MOX (2g q8h) | −4.6 | −3.8 | >24 | >23.3 | >22.5 | >21.3 | 157.5 | |
| CTX (2g qd) | −2.0 | 3.1 | 3.5 | 2.3 | 0.4 | NA | 10.5 | |
| CFZ/SBT (2g qd) | −2.8 | 3.0 | 7.6 | 3.8 | 3.5 | NA | 32.4 | |
| CFZ/SBT (2g q8h) | −2.7 | 3.0 | 12.0 | 4.9 | 2.8 | NA | 52.3 | |
Note: Negative numbers indicate reduction in CFU from 0 h.
Abbreviations: CFU, colony forming units; CTX, cefotaxime; CFZ/SBT, cefoperazone/sulbactam; ESBL, extended-spectrum β-lactamase; IE, the area between the control growth and antibacterial killing curves; Δlog N24, the bacterial count difference between time 0 and 24 h; MOX, moxalactam; NA, not applicable; MKD, maximum kill down; qd, once-daily; q12h, twice-daily; q8h, thrice-daily; RT, bacterial growth recovery time; T90%, T99%, and T99.9%, the time required for microbial initial count to be reduced by 90%, 99%, and 99.9%, respectively.