TABLE 3

Activities of ceftazidime-avibactam and comparator antimicrobial agents when tested against Gram-negative organisms isolated from patients hospitalized with pneumonia (United States, 2011 to 2015)

Organism/antimicrobial agent (no. of isolates)MIC50 (μg/ml)MIC90 (μg/ml)CLSIaEUCASTa
% S% I% R% S% I% R
P. aeruginosa (3,402)
    Ceftazidime-avibactam2496.63.4b96.63.4
    Ceftazidime23282.44.613.082.417.6
    Cefepime41683.410.06.683.416.6
    Piperacillin-tazobactam4>6478.210.611.378.221.8
    Meropenem0.5879.17.013.979.113.77.1
    Imipenem1871.99.418.881.215.63.1
    Ciprofloxacin0.25>475.66.518.068.37.324.4
    Levofloxacin0.5>472.58.019.561.910.627.5
    Gentamicin2>884.84.810.484.815.2
    Amikacin41695.31.82.889.95.44.7
    Colistin1299.60.30.199.90.1
Enterobacteriaceae (6,209)
    Ceftazidime-avibactam0.120.599.90.1b99.90.1
    Ceftazidime0.253285.01.513.582.22.915.0
    Ceftriaxone0.12>880.71.318.080.71.318.0
    Cefepime0.06888.03.28.8b85.93.710.4
    Ampicillin-sulbactam16>3245.017.237.845.055.0
    Piperacillin-tazobactam26487.64.87.683.04.612.4
    Meropenem≤0.06≤0.0696.80.52.897.21.01.7
    Imipenem≤0.12194.32.43.396.71.81.5
    Aztreonam≤0.12>1684.51.414.182.42.115.5
    Ciprofloxacin≤0.03>481.81.616.777.32.720.0
    Levofloxacin≤0.12>483.41.714.979.12.718.2
    Gentamicin≤1491.11.67.289.71.48.9
    Amikacin1498.31.30.497.11.21.7
    Tigecycline0.25198.51.5<0.1b93.55.01.5
    Colistin≤0.5>877.322.7
A. baumannii (443)
    Ceftazidime-avibactam16>32
    Ceftazidime>32>3237.54.158.5
    Cefepime>16>1636.711.352.0
    Ampicillin-sulbactam16>3248.515.436.1
    Piperacillin-tazobactam>64>6432.39.858.0
    Meropenem>8>841.51.856.741.57.451.0
    Ciprofloxacin>4>434.30.765.034.365.7
    Levofloxacin>4>436.12.361.635.20.963.9
    Gentamicin>8>845.64.150.345.654.4
    Amikacin8>3263.43.433.259.53.936.6
    Colistin1293.76.393.76.3
  • a Criteria as published by CLSI (17) and EUCAST (14). R, resistant; I, intermediate; S, susceptible.

  • b Breakpoint from FDA package inserts (10, 20).