TABLE 3.
In vitro activities of β-lactams and comparators tested against Enterobacteriaceae and P. aeruginosa encoding metallo-β-lactamases collected from 2012 to 2014
| Organism, genotype (no.), and druga | MIC (μg/ml) |
% susceptibleb |
|||
|---|---|---|---|---|---|
| Range | MIC50 | MIC90 | CLSI | EUCAST | |
| All Enterobacteriaceae (38,266) | |||||
| Ceftazidime | ≤0.015 to >128 | 0.25 | 64 | 76.9 | 73.4 |
| Cefepime | ≤0.12 to >16 | ≤0.12 | >16 | 78.8 | 77.0 |
| Aztreonam | ≤0.015 to >128 | 0.12 | 64 | 75.7 | 73.1 |
| Aztreonam-avibactamc | ≤0.015 to >128 | 0.03 | 0.12 | NAd | NA |
| Piperacillin-tazobactam | ≤0.25 to >128 | 2 | 64 | 84.7 | 78.1 |
| Meropenem | ≤0.004 to >8 | 0.03 | 0.12 | 97.3 | 97.7 |
| Amikacin | ≤0.25 to >32 | 2 | 8 | 96.6 | 93.8 |
| Tigecycline | ≤0.015 to >8 | 0.5 | 2 | 92.9 | 82.5 |
| Levofloxacin | ≤0.03 to >4 | 0.06 | >4 | 75.7 | 73.5 |
| Colistin | ≤0.015 to >4 | ≤0.12 | >4 | NA | 83.2 |
| MBL-positive Enterobacteriaceae | |||||
| NDM positive (72) | |||||
| Ceftazidime | 128 to >128 | >128 | >128 | 0.0 | 0.0 |
| Cefepime | 1 to >16 | >16 | >16 | 0.0 | 1.4 |
| Aztreonam | ≤0.015 to >128 | 128 | >128 | 20.8 | 16.7 |
| Aztreonam-avibactam | ≤0.015 to 8 | 0.12 | 0.5 | NA | NA |
| Piperacillin-tazobactam | 32 to >128 | >128 | >128 | 0.0 | 0.0 |
| Meropenem | 1 to >8 | >8 | >8 | 1.4 | 2.8 |
| Amikacin | 1 to >32 | >32 | >32 | 41.7 | 37.5 |
| Tigecycline | 0.06 to 8 | 1 | 4 | 87.5 | 61.1 |
| Levofloxacin | 0.06 to >4 | >4 | >4 | 22.2 | 12.5 |
| Colistin | ≤0.015 to >4 | ≤0.12 | >4 | NA | 86.1 |
| IMP positive (27) | |||||
| Ceftazidime | 64 to >128 | >128 | >128 | 0.0 | 0.0 |
| Cefepime | 8 to >16 | >16 | >16 | 0.0 | 0.0 |
| Aztreonam | 0.06 to >128 | 64 | >128 | 29.6 | 29.6 |
| Aztreonam-avibactam | 0.03 to 4 | 0.25 | 1 | NA | NA |
| Piperacillin-tazobactam | 0.5 to >128 | 128 | >128 | 40.7 | 25.9 |
| Meropenem | 0.5 to >8 | 4 | >8 | 18.5 | 40.7 |
| Amikacin | 1 to >32 | 2 | >32 | 66.7 | 59.3 |
| Tigecycline | 0.12 to 8 | 1 | 2 | 96.3 | 77.8 |
| Levofloxacin | 0.06 to >4 | 2 | >4 | 55.6 | 40.7 |
| Colistin | 0.03 to >4 | ≤0.12 | >4 | NA | 88.9 |
| VIM positive (64) | |||||
| Ceftazidime | 0.25 to >128 | >128 | >128 | 6.3 | 6.3 |
| Cefepime | ≤0.12 to >16 | >16 | >16 | 7.8 | 7.8 |
| Aztreonam | ≤0.015 to >128 | 8 | 128 | 48.4 | 42.2 |
| Aztreonam-avibactam | ≤0.015 to 2 | 0.12 | 1 | NA | NA |
| Piperacillin-tazobactam | 1 to >128 | >128 | >128 | 6.3 | 1.6 |
| Meropenem | 0.25 to >8 | 8 | >8 | 14.1 | 25.0 |
| Amikacin | 1 to >32 | 8 | >32 | 79.7 | 59.4 |
| Tigecycline | 0.25 to >8 | 1 | 4 | 87.5 | 60.9 |
| Levofloxacin | 0.06 to >4 | >4 | >4 | 28.1 | 23.4 |
| Colistin | 0.03 to >4 | ≤0.12 | >4 | NA | 70.3 |
| All P. aeruginosa (8,010) | |||||
| Ceftazidime | 0.06 to >128 | 2 | 64 | 77.4 | 77.4 |
| Cefepime | ≤0.12 to >16 | 4 | 16 | 78.6 | 78.6 |
| Aztreonam | ≤0.015 to >128 | 8 | 32 | 61.4 | 3.4 |
| Aztreonam-avibactamc | ≤0.015 to >128 | 8 | 32 | NA | NA |
| Piperacillin-tazobactam | ≤0.25 to >128 | 8 | >128 | 69.1 | 69.1 |
| Meropenem | ≤0.06 to >8 | 0.5 | >8 | 73.3 | 73.3 |
| Amikacin | ≤0.25 to >32 | 4 | 16 | 90.2 | 85.1 |
| Levofloxacin | ≤0.03 to >4 | 0.5 | >4 | 71.7 | 63.2 |
| Colistin | ≤0.06 to >8 | 0.5 | 1 | 99.5 | 99.7 |
| MBL-positive P. aeruginosa | |||||
| NDM positive (3) | |||||
| Ceftazidime | >128 | 0.0 | 0.0 | ||
| Cefepime | >16 | 0.0 | 0.0 | ||
| Aztreonam | >128 | 0.0 | 0.0 | ||
| Aztreonam-avibactam | 16 to >128 | NA | NA | ||
| Piperacillin-tazobactam | >128 | 0.0 | 0.0 | ||
| Meropenem | >8 | 0.0 | 0.0 | ||
| Amikacin | >32 | 0.0 | 0.0 | ||
| Levofloxacin | >4 | 0.0 | 0.0 | ||
| Colistin | ≤0.06 to 2 | 100 | 100 | ||
| IMP positive (35) | |||||
| Ceftazidime | 64 to >128 | >128 | >128 | 0.0 | 0.0 |
| Cefepime | >16 | >16 | >16 | 0.0 | 0.0 |
| Aztreonam | 4 to >128 | 32 | 128 | 17.1 | 0.0 |
| Aztreonam-avibactam | 2 to 128 | 32 | 64 | NA | NA |
| Piperacillin-tazobactam | 4 to >128 | 128 | >128 | 14.3 | 14.3 |
| Meropenem | 4 to >8 | >8 | >8 | 0.0 | 0.0 |
| Amikacin | 4 to >32 | 32 | >32 | 40.0 | 28.6 |
| Levofloxacin | 1 to >4 | >4 | >4 | 5.7 | 5.7 |
| Colistin | 0.12 to 4 | 0.5 | 2 | 97.1 | 100 |
| VIM positive (270) | |||||
| Ceftazidime | 2 to >128 | 64 | >128 | 3.0 | 3.0 |
| Cefepime | 8 to >16 | >16 | >16 | 4.4 | 4.4 |
| Aztreonam | 0.5 to >128 | 16 | 64 | 27.8 | 0.4 |
| Aztreonam-avibactam | 0.25 to >128 | 16 | 32 | NA | NA |
| Piperacillin-tazobactam | 16 to >128 | 64 | >128 | 3.7 | 3.7 |
| Meropenem | 1 to >8 | >8 | >8 | 2.2 | 2.2 |
| Amikacin | 0.5 to >32 | >32 | >32 | 16.7 | 11.1 |
| Levofloxacin | 0.25 to >4 | >4 | >4 | 6.3 | 5.2 |
| Colistin | ≤0.06 to 2 | 0.5 | 1 | 100 | 100 |
Colistin was tested with 0.002% polysorbate 80 against isolates collected in 2012 and 2013 per the recommendation of the CLSI Enterobacteriaceae Working Group and tested with and without polysorbate 80 against isolates collected in 2014. Values for colistin tested with 0.002% polysorbate 80 are shown.
CLSI susceptibilities were defined by CLSI document M100-S25 (14). Tigecycline susceptibilities in the CLSI category were defined by the FDA (54). EUCAST susceptibilities were defined by Breakpoint Tables for Interpretation of MICs and Zone Diameters, version 5.0 (55).
Aztreonam-avibactam was tested at a fixed concentration of 4 μg/ml of avibactam.
NA, not applicable (no breakpoint defined).