Table 3

Potency of AN3365 and comparator antimicrobial agents tested against P. aeruginosa and A. baumannii clinical isolates

Organism (no. of strains tested) and antimicrobial agentMIC (μg/ml)% susceptible/resistant by criteria of:
Range50%90%CLSIaEUCASTb
P. aeruginosa
    Wild type (50)
        AN33651–1628c/——/—
        Piperacillin-tazobactam0.5–>12843286.0/6.086.0/14.0
        Ceftazidime≤1–>3241688.0/8.088.0/12.0
        Cefepime≤1–322892.0/2.092.0/8.0
        Imipenem0.25–41294.0/0.0100.0/0.0
        Levofloxacin≤0.5–>16≤0.5292.0/6.084.0/8.0
        Gentamicin≤0.5–>161498.0/2.098.0/2.0
    Carbapenem resistant (51)
        MBL negative (32)
            AN33651–1648—/——/—
            Piperacillin-tazobactam32–>128>128>12816.0/84.00.0/78.1
            Ceftazidime8–>32>32>324.0/92.03.1/93.8
            Cefepime8–>3232>324.0/72.03.1/78.1
            Imipenem8–>6416>640.0/84.00.0/100.0
            Levofloxacin≤0.5–>1616>168.0/84.09.4/84.4
            Gentamicin≤0.5–>16>16>1632.0/44.025.0/56.3
        MBL positive (19)d
            AN33652–16416—/——/—
            Piperacillin-tazobactam32–>128128>12826.9/73.10.0/78.9
            Ceftazidime32–>32>32>320.0/100.00.0/100.0
            Cefepime16–>32>32>320.0/88.50.0/84.2
            Imipenem16–>64>64>640.0/100.00.0/100.0
            Levofloxacin4–>1616>163.8/92.30.0/94.7
            Gentamicin8–>16>16>160.0/96.20.0/94.7
A. baumannii
    Wild type (25)
        AN33650.5–828—/——/—
        Piperacillin-tazobactam≤0.06–16≤0.068100.0/0.0—/—
        Ceftazidime2–1681688.0/0.0—/—
        Cefepime≤1–162896.0/0.0—/—
        Imipenem0.12–40.250.25100.0/0.096.0/0.0
        Levofloxacin≤0.5–>16≤0.5484.0/8.080.0/16.0
        Gentamicin≤0.5–>16≤0.5292.0/8.092.0/8.0
        Tigecyclinee0.06–10.121100.0/0.0—/—
    Multidrug resistant (26)
        AN33654–32816—/——/—
        Piperacillin-tazobactam≤0.06–>128>128>1284.8/95.2—/—
        Ceftazidime32–>32>32>320.0/100.0—/—
        Cefepime8–>3232>324.8/71.4—/—
        Imipenem8–>6464>640.0/90.50.0/90.5
        Levofloxacin2–>1616>160.0/95.20.0/100.0
        Gentamicin16–>16>16>160.0/100.00.0/100.0
        Tigecyclinee0.25–82876.9/11.5—/—
S. maltophilia wild type (50)
    AN33650.12–824—/——/—
    Piperacillin-tazobactam8–>128>128>128—/——/—
    Ceftazidime2–>3232>3220.0/58.0—/—
    Cefepime2–>32>32>32—/——/—
    Imipenem16–>64>64>64—/——/—
    Levofloxacin≤0.5–>161486.0/8.0—/—
    Gentamicin≤0.5–>1616>16—/——/—
    Tigecyclinee0.12–20.51—/——/—
B. cepacia wild type (50)
    AN33650.5–128832c/——/—
    Piperacillin-tazobactam≤0.06–>128232—/——/—
    Ceftazidime≤1–>3241686.0/6.0—/—
    Cefepime≤1–>32832—/——/—
    Imipenem0.25–>64832—/——/—
    Levofloxacin≤0.5–161870.0/20.0—/—
    Gentamicin1–>16>16>16—/——/—
    Tigecyclinee0.12–1614—/——/—
  • a Criteria for susceptibility as published by the Clinical and Laboratory Standards Institute (34), when available.

  • b Criteria for susceptibility as European Committee on Antimicrobial Susceptibility Testing (http://www.eucast.org/clinical_breakpoints/), when available.

  • c —, breakpoint not available.

  • d Includes 14 VIM-like strains, three SPM-1 strains, one GIM-1 strain, and one IMP-15 producer.

  • e Tigecycline breakpoints approved by the FDA for Enterobacteriaceae (≤2 μg/ml for susceptible; ≥8 μg/ml for resistance) were applied for comparison purposes (35).