TABLE 2

Activity of ceftazidime-avibactam and comparator antimicrobial agents when tested against Enterobacteriaceae, P. aeruginosa, and selected resistant subsetsa

Organism category and antimicrobial agent (no. of isolates tested)MIC (μg/ml)CLSIbEUCAST
MIC50MIC90%S%R%S%R
Enterobacteriaceae
    All isolates (36,380)
        Ceftazidime-avibactam0.120.2599.90.1*99.90.1
        Ceftriaxone≤0.06>885.313.685.313.6
        Ceftazidime0.25888.89.986.211.2
        Cefepime≤0.12291.26.789.87.7
        Piperacillin-tazobactam21692.74.189.87.3
        Meropenem≤0.06≤0.0698.51.398.70.7
        Levofloxacin≤0.12>482.615.678.718.8
        Gentamicin≤1291.27.690.28.8
        Amikacin2499.20.298.40.8
        Tigecycline0.25198.00.1*92.72.0
        Colistin≤0.5>8 78.221.8
    MDR (2,953)c
        Ceftazidime-avibactam0.25199.20.8*99.20.8
        Ceftriaxone>8>819.777.219.777.2
        Ceftazidime32>3229.663.922.170.4
        Cefepime16>1637.451.132.056.8
        Piperacillin-tazobactam16>6452.729.845.247.3
        Meropenem≤0.06882.215.384.78.9
        Levofloxacin>4>420.670.611.284.8
        Gentamicin>8>838.250.834.561.8
        Amikacin41691.12.284.48.9
        Tigecycline0.5488.90.3*76.911.1
        Colistin≤0.5>8 60.739.3
    XDR (448)d
        Ceftazidime-avibactam0.5297.82.2*97.82.2
        Ceftriaxone>8>82.097.32.097.3
        Ceftazidime>32>325.491.52.994.6
        Cefepime>16>1610.579.96.485.8
        Piperacillin-tazobactam>64>647.183.76.592.9
        Meropenem8>821.272.527.548.2
        Levofloxacin>4>48.784.82.296.4
        Gentamicin8>827.050.023.473.0
        Amikacin163260.29.646.539.8
        Tigecycline0.5490.00.2*81.010.0
        Colistin≤0.5>8 61.338.7
    CRE (513)e
        Ceftazidime-avibactam0.5297.52.5*97.52.5
        Ceftriaxone>8>82.197.52.197.5
        Ceftazidime>32>324.393.02.395.7
        Cefepime>16>168.477.93.287.1
        Piperacillin-tazobactam>64>643.191.22.796.9
        Meropenem>8>82.789.710.352.4
        Levofloxacin>4>423.472.915.081.3
        Gentamicin8>849.533.944.450.5
        Amikacin83268.27.051.531.8
        Tigecycline0.5198.80.0*90.31.2
        Colistin≤0.5>8 79.120.9
    Ceftriaxone-nonsusceptible K. pneumoniae (1,063)f
        Ceftazidime-avibactam0.25199.60.4*99.60.4
        Ceftriaxone>8>80.097.50.097.5
        Ceftazidime>32>329.084.53.491.0
        Cefepime>16>1612.374.48.981.6
        Piperacillin-tazobactam32>6444.744.331.855.3
        Meropenem≤0.06>864.232.867.222.3
        Levofloxacin>4>435.158.624.167.9
        Gentamicin8>846.545.342.153.5
        Amikacin43281.04.270.319.0
        Tigecycline0.5198.80.0*91.21.2
        Colistin≤0.54 88.911.1
    Colistin-nonsusceptible K. pneumoniae (205)
        Ceftazidime-avibactam0.25299.50.5*99.50.5
        Ceftriaxone>8>842.955.642.955.6
        Ceftazidime32>3242.057.140.058.0
        Cefepime16>1646.751.146.751.1
        Piperacillin-tazobactam16>6451.245.941.048.8
        Meropenem≤0.06>862.437.662.431.2
        Levofloxacin>4>446.850.242.054.1
        Gentamicin≤1>869.825.965.930.2
        Amikacin23277.67.366.822.4
        Tigecycline0.5299.50.0*89.30.5
        Colistin>8>8 0.0100.0
    Ceftazidime-nonsusceptible (≥8 μg/ml) Enterobacter cloacae (831)g
        Ceftazidime-avibactam0.5199.30.7*99.30.7
        Ceftriaxone>8>80.099.40.099.4
        Ceftazidime>32>320.095.80.0100.0
        Cefepime2>1665.118.343.124.1
        Piperacillin-tazobactam64>6423.835.916.676.2
        Meropenem≤0.060.2593.55.194.91.3
        Levofloxacin≤0.12>482.312.975.520.6
        Gentamicin≤1>883.512.882.216.5
        Amikacin1499.30.698.00.7
        Tigecycline0.25298.30.0*89.21.7
        Colistin≤0.5>8 84.615.4
P. aeruginosa
    All isolates (7,868)
        Ceftazidime-avibactam2497.12.9*97.12.9
        Ceftazidime23284.710.984.715.3
        Cefepime21685.65.285.614.4
        Piperacillin-tazobactam46481.09.481.019.0
        Meropenem0.5881.312.881.36.8
        Levofloxacin0.5>474.518.665.334.7
        Gentamicin2887.08.487.013.0
        Amikacin4896.51.991.83.5
        Colistin1299.60.499.60.4
    MDR (1,562)
        Ceftazidime-avibactam41686.513.5*86.513.5
        Ceftazidime16>3243.641.643.656.4
        Cefepime16>1641.723.041.758.3
        Piperacillin-tazobactam64>6431.236.231.268.8
        Meropenem8>820.058.220.032.4
        Levofloxacin>4>418.765.09.590.5
        Gentamicin4>855.432.355.444.6
        Amikacin83287.17.673.912.9
        Colistin1299.20.899.20.8
    XDR (717)
        Ceftazidime-avibactam83275.924.1*75.924.1
        Ceftazidime32>3221.560.021.578.5
        Cefepime16>1617.338.117.382.7
        Piperacillin-tazobactam>64>647.752.67.792.3
        Meropenem>8>83.179.63.152.2
        Levofloxacin>4>45.378.42.297.8
        Gentamicin8>839.647.139.660.4
        Amikacin8>3280.811.664.219.2
        Colistin1299.30.799.30.7
    Ceftazidime, meropenem, and piperacillin-tazobactam-nonsusceptible (628)
        Ceftazidime-avibactam83271.828.2*71.828.2
        Ceftazidime32>320.076.00.0100.0
        Cefepime16>1618.341.918.381.7
        Piperacillin-tazobactam>64>640.065.10.0100.0
        Meropenem>8>80.081.20.050.6
        Levofloxacin>4>421.966.213.686.4
        Gentamicin4>854.037.454.046.0
        Amikacin8>3283.010.771.717.0
        Colistin1299.50.599.50.5
  • a CLSI and EUCAST criteria are as published previously (33, 34).

  • b *, breakpoints from the FDA package insert (17, 35).

  • c MDR organisms included the following: Citrobacter freundii (n = 59), C. koseri (n = 1), Enterobacter aerogenes (n = 42), E. cloacae (n = 119), E. cloacae species complex (n = 153), Escherichia coli (n = 797), Hafnia alvei (n = 3), Klebsiella oxytoca (n = 55), K. pneumoniae (n = 793), Morganella morganii (n = 174), Proteus mirabilis (n = 426), P. vulgaris (n = 5), P. vulgaris group (n = 1), Providencia rettgeri (n = 17), P. stuartii (n = 191), Raoultella ornithinolytica (n = 1), Serratia liquefaciens (n = 1), S. marcescens (n = 112), Raoultella sp. (n = 2), and Serratia sp. (n = 1).

  • d XDR organisms included the following: Citrobacter freundii (n = 9), Enterobacter aerogenes (n = 1), E. cloacae (n = 44), Escherichia coli (n = 12), Klebsiella oxytoca (n = 8), K. pneumoniae (n = 297), Morganella morganii (n = 17), Proteus mirabilis (n = 19), Providencia stuartii (n = 18), Raoultella ornithinolytica (n = 1), Serratia marcescens (n = 21), and Raoultella sp. (n = 1).

  • e The results of the molecular characterization of these isolates are shown in Table 3. CRE organisms included the following: Citrobacter freundii (n = 6), Enterobacter aerogenes (n = 13), E. cloacae (n = 5), E. cloacae species complex (n = 50), Escherichia coli (n = 24), Klebsiella oxytoca (n = 16), K. pneumoniae (n = 368), Proteus mirabilis (n = 4), Providencia stuartii (n = 2), Raoultella ornithinolytica (n = 1), Serratia marcescens (n = 22), and Raoultella sp. (n = 2).

  • f According to CLSI criteria; ≥2 μg/ml (33).

  • g According to CLSI criteria; ≥8 μg/ml (33).