TABLE 2.
Comparison of susceptibility rates for ceftazidime-avibactam (CZA) and ceftolozane-tazobactam (C/T) among meropenem-nonsusceptible P. aeruginosa isolates stratified by the presence of nonsusceptibility to other β-lactam agents
| β-Lactam agent(s)a to which isolates were NS (no. of isolates/total, %) | S to CZA (no. of isolates, %) | S to C/T (no. of isolates, %) | P valueb |
|---|---|---|---|
| FEP (168/290, 58) | 114, 68 | 142, 85 | 0.0003 |
| CAZ (157/290, 54) | 105, 67 | 132, 84 | 0.0006 |
| TZP (185/290, 64) | 133, 72 | 159, 86 | 0.0013 |
| ATM (183/290, 63) | 132, 72 | 159, 87 | 0.0007 |
| FEP and CAZ (133/290, 46) | 82, 62 | 108, 81 | 0.0006 |
| FEP and TZP (147/290, 51) | 97, 66 | 122, 83 | 0.0012 |
| FEP and ATM (131/290, 45) | 82, 63 | 108, 82 | 0.0005 |
| CAZ and TZP (145/290, 50) | 95, 66 | 121, 83 | 0.0007 |
| CAZ and ATM (121/290, 42) | 73, 60 | 99, 82 | 0.0004 |
| TZP and ATM (148/290, 51) | 99, 67 | 125, 85 | 0.0006 |
| FEP, CAZ, and TZP (127/290, 44) | 78/127, 61 | 103/127, 81 | 0.0008 |
| FEP, CAZ, and ATM (106/290, 37) | 59/106, 56 | 84/106, 79 | 0.0004 |
| FEP, TZP, and ATM (121/290, 42) | 73/121, 60 | 98/121, 81 | 0.0006 |
| CAZ, TZP, and ATM (118/290, 41) | 70/118, 59 | 96/118, 81 | 0.0003 |
| All 4 β-lactam agents (103/290, 36) | 56/103, 54 | 81/103, 79 | 0.0004 |
a
Abbreviations: S, susceptible; NS, nonsusceptible; ATM, aztreonam; FEP, cefepime; CZA, ceftazidime-avibactam; C/T, ceftolozane-tazobactam; CAZ, ceftazidime; TZP, piperacillin-tazobactam.
b
Comparisons were conducted using Fisher's exact test.