TABLE 2.
Antimicrobial activity of ceftazidime-avibactam tested against P. aeruginosa from U.S. medical centers (2012 to 2015)
| Resistance groupb | No. (cumulative %) of isolates at MIC (mg/liter): |
MIC50 (mg/liter) | MIC90 (mg/liter) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| ≤0.25 | 0.5 | 1 | 2 | 4 | 8 | 16 | 32 | >32 | |||
| All isolates (n = 7,452) | 128 (1.7) | 390 (7.0) | 2,843 (45.1) | 2,409 (77.4) | 1,043 (91.4) | 415 (97.0)a | 133 (98.8) | 44 (99.4) | 47 (100.0) | 2 | 4 |
| CAZ-NS (≥16 mg/liter; n = 1,168) | 2 (0.2) | 8 (0.9) | 88 (8.4) | 282 (32.5) | 320 (59.9) | 246 (81.0)a | 131 (92.2) | 44 (96.0) | 47 (100.0) | 4 | 16 |
| MEM-NS (≥4 mg/liter; n = 1,341) | 2 (0.1) | 10 (0.9) | 127 (10.4) | 323 (34.5) | 416 (65.5) | 278 (86.2)a | 104 (94.0) | 37 (96.7) | 44 (100.0) | 4 | 16 |
| PT-NS (≥32 mg/liter; n = 1,449) | 2 (0.1) | 15 (1.2) | 113 (9.0) | 326 (31.5) | 442 (62.0) | 340 (85.4)a | 125 (94.1) | 42 (97.0) | 44 (100.0) | 4 | 16 |
| NS to CAZ, MEM, and PT (n = 607) | 1 (0.2) | 15 (2.6) | 88 (17.1) | 154 (42.5) | 174 (71.2)a | 98 (87.3) | 36 (93.2) | 41 (100.0) | 8 | 32 | |
| Levofloxacin-NS (≥4 mg/liter; n = 1,868) | 19 (1.0) | 84 (5.5) | 332 (23.3) | 459 (47.9) | 508 (75.1) | 286 (90.4)a | 101 (95.8) | 36 (97.7) | 43 (100.0) | 4 | 8 |
| Gentamicin-NS (≥8 mg/liter; n = 873) | 16 (1.8) | 42 (6.6) | 155 (24.4) | 242 (52.1) | 190 (73.9) | 120 (87.6)a | 46 (92.9) | 25 (95.8) | 37 (100.0) | 2 | 16 |
| Amikacin-NS (≥32 mg/liter; n = 224) | 6 (2.7) | 13 (8.5) | 38 (25.4) | 52 (48.7) | 46 (69.2) | 23 (79.5)a | 17 (87.1) | 10 (91.5) | 19 (100.0) | 4 | 32 |
| Colistin-NS (≥4 mg/liter; n = 45) | 1 (2.2) | 1 (4.4) | 17 (42.2) | 15 (75.6) | 5 (86.7) | 1 (88.9)a | 3 (95.6) | 0 (95.6) | 2 (100.0) | 2 | 16 |
| MDR (n = 1,151) | 4 (0.3) | 8 (1.0) | 74 (7.5) | 241 (28.4) | 333 (57.3) | 285 (82.1)a | 118 (92.4) | 42 (96.0) | 46 (100.0) | 4 | 16 |
| XDR (n = 698) | 1 (0.1) | 4 (0.7) | 28 (4.7) | 109 (20.3) | 179 (46.0) | 208 (75.8)a | 88 (88.4) | 36 (93.6) | 45 (100.0) | 8 | 32 |
| PDR (n = 2) | 2 (100.0) | >32 | |||||||||
a
Values in bold indicate percent susceptible to ceftazidime-avibactam.
b
Abbreviations: CAZ, ceftazidime; NS, nonsusceptible; MEM, meropenem; PT, piperacillin-tazobactam; MDR, multidrug resistant; XDR, extensively drug resistant; PDR, pan-drug resistant.