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 drugaMIC (μg/ml)% susceptibleb
RangeMIC50MIC90CLSIEUCAST
All Enterobacteriaceae (38,266)
    Ceftazidime≤0.015 to >1280.256476.973.4
    Cefepime≤0.12 to >16≤0.12>1678.877.0
    Aztreonam≤0.015 to >1280.126475.773.1
    Aztreonam-avibactamc≤0.015 to >1280.030.12NAdNA
    Piperacillin-tazobactam≤0.25 to >12826484.778.1
    Meropenem≤0.004 to >80.030.1297.397.7
    Amikacin≤0.25 to >322896.693.8
    Tigecycline≤0.015 to >80.5292.982.5
    Levofloxacin≤0.03 to >40.06>475.773.5
    Colistin≤0.015 to >4≤0.12>4NA83.2
MBL-positive Enterobacteriaceae
    NDM positive (72)
        Ceftazidime128 to >128>128>1280.00.0
        Cefepime1 to >16>16>160.01.4
        Aztreonam≤0.015 to >128128>12820.816.7
        Aztreonam-avibactam≤0.015 to 80.120.5NANA
        Piperacillin-tazobactam32 to >128>128>1280.00.0
        Meropenem1 to >8>8>81.42.8
        Amikacin1 to >32>32>3241.737.5
        Tigecycline0.06 to 81487.561.1
        Levofloxacin0.06 to >4>4>422.212.5
        Colistin≤0.015 to >4≤0.12>4NA86.1
    IMP positive (27)
        Ceftazidime64 to >128>128>1280.00.0
        Cefepime8 to >16>16>160.00.0
        Aztreonam0.06 to >12864>12829.629.6
        Aztreonam-avibactam0.03 to 40.251NANA
        Piperacillin-tazobactam0.5 to >128128>12840.725.9
        Meropenem0.5 to >84>818.540.7
        Amikacin1 to >322>3266.759.3
        Tigecycline0.12 to 81296.377.8
        Levofloxacin0.06 to >42>455.640.7
        Colistin0.03 to >4≤0.12>4NA88.9
    VIM positive (64)
        Ceftazidime0.25 to >128>128>1286.36.3
        Cefepime≤0.12 to >16>16>167.87.8
        Aztreonam≤0.015 to >128812848.442.2
        Aztreonam-avibactam≤0.015 to 20.121NANA
        Piperacillin-tazobactam1 to >128>128>1286.31.6
        Meropenem0.25 to >88>814.125.0
        Amikacin1 to >328>3279.759.4
        Tigecycline0.25 to >81487.560.9
        Levofloxacin0.06 to >4>4>428.123.4
        Colistin0.03 to >4≤0.12>4NA70.3
All P. aeruginosa (8,010)
    Ceftazidime0.06 to >12826477.477.4
    Cefepime≤0.12 to >1641678.678.6
    Aztreonam≤0.015 to >12883261.43.4
    Aztreonam-avibactamc≤0.015 to >128832NANA
    Piperacillin-tazobactam≤0.25 to >1288>12869.169.1
    Meropenem≤0.06 to >80.5>873.373.3
    Amikacin≤0.25 to >3241690.285.1
    Levofloxacin≤0.03 to >40.5>471.763.2
    Colistin≤0.06 to >80.5199.599.7
MBL-positive P. aeruginosa
    NDM positive (3)
        Ceftazidime>1280.00.0
        Cefepime>160.00.0
        Aztreonam>1280.00.0
        Aztreonam-avibactam16 to >128NANA
        Piperacillin-tazobactam>1280.00.0
        Meropenem>80.00.0
        Amikacin>320.00.0
        Levofloxacin>40.00.0
        Colistin≤0.06 to 2100100
    IMP positive (35)
        Ceftazidime64 to >128>128>1280.00.0
        Cefepime>16>16>160.00.0
        Aztreonam4 to >1283212817.10.0
        Aztreonam-avibactam2 to 1283264NANA
        Piperacillin-tazobactam4 to >128128>12814.314.3
        Meropenem4 to >8>8>80.00.0
        Amikacin4 to >3232>3240.028.6
        Levofloxacin1 to >4>4>45.75.7
        Colistin0.12 to 40.5297.1100
    VIM positive (270)
        Ceftazidime2 to >12864>1283.03.0
        Cefepime8 to >16>16>164.44.4
        Aztreonam0.5 to >128166427.80.4
        Aztreonam-avibactam0.25 to >1281632NANA
        Piperacillin-tazobactam16 to >12864>1283.73.7
        Meropenem1 to >8>8>82.22.2
        Amikacin0.5 to >32>32>3216.711.1
        Levofloxacin0.25 to >4>4>46.35.2
        Colistin≤0.06 to 20.51100100
  • a 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.

  • b 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).

  • c Aztreonam-avibactam was tested at a fixed concentration of 4 μg/ml of avibactam.

  • d NA, not applicable (no breakpoint defined).