TABLE 1.
Summary of ceftazidime-avibactam activity tested against P. aeruginosa isolates from U.S. hospitals (2012 to 2013), including antimicrobial-resistant subsets
| Organism (no. tested)a | No. of isolates (cumulative %) inhibited at ceftazidime-avibactam MIC (μg/ml) of: |
MIC |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| ≤0.25 | 0.5 | 1 | 2 | 4 | 8 | 16 | 32 | >32 | 50% | 90% | |
| All isolates (3,902) | 60 (1.5) | 194 (6.5) | 1,523 (45.5) | 1,217 (76.7) | 563 (91.2) | 223 (96.9b) | 74 (98.8) | 23 (99.4) | 25 (100.0) | 2 | 4 |
| CAZ-NS (634) | 1 (0.2) | 41 (6.6) | 149 (30.1) | 181 (58.7) | 141 (80.9b) | 73 (92.4) | 23 (96.1) | 25 (100.0) | 4 | 16 | |
| MEM-NS (702) | 8 (1.1) | 63 (10.1) | 172 (34.6) | 218 (65.7) | 146 (86.5b) | 54 (94.2) | 18 (96.7) | 23 (100.0) | 4 | 16 | |
| P-T-NS (837) | 4 (0.5) | 62 (7.9) | 189 (30.5) | 267 (62.4) | 196 (85.8b) | 72 (94.4) | 22 (97.0) | 25 (100.0) | 4 | 16 | |
| MER-NS, CAZ-NS, and P-T-NS (330) | 1 (0.3) | 4 (1.5) | 45 (15.2) | 87 (45.1) | 100 (71.8b) | 53 (87.9) | 17 (93.0) | 23 (100.0) | 8 | 32 | |
| MDR (580) | 1 (0.2) | 3 (0.7) | 31 (6.0) | 113 (25.5) | 174 (55.5) | 148 (81.0b) | 64 (92.1) | 21 (95.7) | 25 (100.0) | 4 | 16 |
| XDR (338) | 1 (0.3) | 8 (2.7) | 51 (17.8) | 88 (43.8) | 101 (73.7b) | 46 (87.3) | 18 (92.6) | 25 (100.0) | 8 | 32 | |
a
CAZ, ceftazidime; MEM, meropenem; P-T, piperacillin-tazobactam; NS, nonsusceptible; MDR, multidrug resistant; XDR, extensively drug-resistant.
b
Percent susceptible according to the U.S. FDA breakpoint criteria (11).