Table 2.
MIC distributions of CXA-201 tested against ceftazidime-resistant Enterobacteriaceae, ESBL-producing P. mirabilis, P. aeruginosa, and B. fragilisa
| Organism (no. tested)b | No. of isolates (cumulative %) inhibited at the following CXA-101–tazobactam MIC (μg/ml)c: |
||||||||
|---|---|---|---|---|---|---|---|---|---|
| ≤0.12 | 0.25 | 0.5 | 1 | 2 | 4 | 8 | 16 | >16 | |
| E. coli, CAZ-R (224) | 2 (0.9) | 5 (3.1) | 42 (21.9) | 72 (54.0)b | 35 (69.6) | 18 (77.7) | 18 (85.7) | 14 (92.0) | 18 (100.0) |
| K. pneumoniae strains | |||||||||
| CAZ-R (186) | 2 (1.1) | 6 (4.3) | 20 (15.1) | 33 (32.8) | 18 (42.5) | 22 (54.3) | 10 (59.7) | 16 (68.3) | 59 (100.0) |
| KPC producers (53) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 2 (3.8) | 51 (100.0) |
| Proteus, indole positive, CAZ-R (82) | 0 (0.0) | 12 (14.6) | 8 (24.4) | 10 (36.6) | 15 (54.9) | 12 (69.5) | 7 (78.0) | 5 (84.1) | 13 (100.0) |
| Enterobacter spp., CAZ-R (90) | 0 (0.0) | 6 (6.7) | 2 (8.9) | 6 (15.6) | 3 (18.9) | 16 (36.7) | 11 (48.9) | 25 (76.7) | 21 (100.0) |
| Citrobacter spp., CAZ-R (108) | 0 (0.0) | 2 (1.9) | 2 (3.7) | 7 (10.2) | 5 (14.8) | 22 (35.2) | 13 (47.2) | 31 (75.9) | 26 (100.0) |
| P. mirabilis with the ESBL phenotype (68) | 0 (0.0) | 5 (7.3) | 28 (48.5) | 15 (70.6) | 7 (80.9) | 5 (88.2) | 4 (94.1) | 2 (97.1) | 2 (100.0) |
| P. aeruginosa (449) | 0 (0.0) | 7 (1.6) | 131 (30.7) | 113 (55.9) | 84 (74.6) | 57 (87.3) | 25 (92.9) | 8 (94.7) | 24 (100.0) |
| CAZ-S, IMI-S (54) | 0 (0.0) | 6 (11.1) | 45 (94.4) | 2 (98.2) | 1 (100.0) | ||||
| CAZ-S, IMI-NS (143) | 0 (0.0) | 3 (2.1) | 75 (54.6) | 58 (95.1) | 3 (97.2) | 0 (0.0) | 3 (99.3) | 1 (100.0) | |
| CAZ-NS, IMI-S (39) | 0 (0.0) | 0 (0.0) | 1 (2.6) | 10 (28.2) | 13 (61.5) | 7 (79.5) | 2 (84.6) | 1 (87.2) | 5 (100.0) |
| CAZ-NS, IMI-NS (213) | 0 (0.0) | 0 (0.0) | 5 (2.4) | 38 (20.2) | 60 (48.4) | 58 (75.6) | 24 (86.9) | 7 (90.9) | 21 (100.0) |
| B. fragilis (41) | 1 (7.4) | 4 (12.2) | 5 (24.4) | 15 (61.0) | 4 (70.7) | 0 (70.7) | 2 (75.6) | 2 (80.5) | 8 (100.0) |
a
In this experiment, the concentration of tazobactam was fixed at 4 μg/ml.
b
Abbreviations: CAZ-R, ceftazidime-resistant; KPC, Klebsiella pneumoniae carbapenemase; ESBL, extended-spectrum β-lactamase (5); CAZ-S, ceftazidime-susceptible; CAZ-NS, ceftazidime-nonsusceptible; IMI-S, imipenem-susceptible; IMI-NS, imipenem-nonsusceptible.
c
The MIC50s are underlined.