Table 2

Potency and spectrum of activity of AN3365 and comparator antimicrobial agents tested against Enterobacteriaceae clinical isolates

Organism (no. of strains tested) and antimicrobial agentMIC (μg/ml)% susceptible/resistant by criteria of:
Range50%90%CLSIaEUCASTb
All Enterobacteriaceae (2,029)
    AN33650.25–40.51c/——/—
    Ampicillin0.5–>64>64>6416.0/81.3—/84.0
    Amoxicillin-clavulanate0.5–>6464>6430.5/63.8—/69.5
    Ceftazidime≤1–>16≤1>1682.7/16.178.9/17.3
    Cefepime≤1–>32≤1492.9/6.186.2/8.4
    Piperacillin-tazobactam≤0.06–>12826486.4/8.182.9/13.6
    Imipenem≤0.03–>641273.5/8.191.9/1.0
    Levofloxacin≤0.5–>16≤0.51681.4/15.977.7/18.6
    Gentamicin≤0.5–>1611687.2/11.185.3/12.8
    Tigecycline0.06–80.5292.2/0.678.6/7.8
    Polymyxin B≤0.25–>81>858.7/41.3—/—
Escherichia coli (252)
    AN33650.5–20.51—/——/—
    Ampicillin0.5–>64>64>6438.5/61.1—/61.5
    Amoxicillin-clavulanate1–>6483264.7/17.1—/35.3
    Ceftazidime≤1–>16≤11685.7/12.784.9/14.3
    Cefepime≤1–>32≤1290.1/9.588.1/9.9
    Piperacillin-tazobactam0.12–>12823287.3/7.584.9/12.7
    Imipenem0.06–160.120.2599.6/0.499.6/0.4
    Levofloxacin≤0.5–>16≤0.5>1666.7/31.766.3/33.3
    Gentamicin≤0.5–>161>1683.3/15.981.7/16.7
    Tigecycline0.06–10.250.5100.0/0.0100.0/0.0
    Polymyxin B≤0.25–80.5197.6/2.4—/—
Klebsiella pneumoniae (261)
    AN33650.25–20.51—/——/—
    Ampicillin1–>64>64>641.5/94.3—/98.5
    Amoxicillin-clavulanate1–>6486461.3/25.3—/38.7
    Ceftazidime≤1–>16≤1>1664.8/34.160.9/35.2
    Cefepime≤1–>32≤1>3275.9/20.366.3/26.4
    Piperacillin-tazobactam0.25–>1288>12869.3/24.961.3/30.7
    Imipenem≤0.03–>640.25190.0/10.090.0/6.1
    Levofloxacin≤0.5–>16≤0.5>1664.8/31.459.4/35.2
    Gentamicin≤0.5–>16≤0.5>1675.5/21.573.9/24.5
    Tigecycline0.12–40.5296.2/0.088.5/3.8
    Polymyxin B0.5–>80.5295.8/4.2—/—
Enterobacter aerogenes (250)
    AN33650.25–20.51—/——/—
    Ampicillin1–>64>64>642.8/95.6—/97.2
    Amoxicillin-clavulanate1–>6464642.4/97.2—/97.6
    Ceftazidime≤1–>16≤1>1679.6/20.477.2/20.4
    Cefepime≤1–>32≤1≤198.4/1.292.8/2.4
    Piperacillin-tazobactam≤0.06–>12846481.2/6.078.0/18.8
    Imipenem≤0.03–161262.4/1.698.4/0.8
    Levofloxacin≤0.5–>16≤0.5190.4/8.890.4/9.6
    Gentamicin≤0.5–>16≤0.5198.4/0.497.6/1.6
    Tigecycline0.12–40.5198.8/0.095.6/1.2
    Polymyxin B≤0.25–>81486.8/13.2—/—
Enterobacter cloacae (252)
    AN33650.25–20.51—/——/—
    Ampicillin4–>64>64>644.8/90.9—/95.2
    Amoxicillin-clavulanate1–>6464642.8/94.0—/97.2
    Ceftazidime≤1–>16≤1>1680.2/19.880.2/19.8
    Cefepime≤1–>32≤1496.4/2.483.7/6.7
    Piperacillin-tazobactam0.12–>128212884.9/10.381.3/15.1
    Imipenem0.06–80.5194.8/0.499.6/0.0
    Levofloxacin≤0.5–>16≤0.5193.3/4.890.9/6.7
    Gentamicin≤0.5–>16≤0.5491.3/7.989.7/8.7
    Tigecycline0.25–40.5196.0/0.092.5/4.0
    Polymyxin B≤0.25–>81>883.3/16.7—/—
Citrobacter freundii (253)
    AN33650.25–20.51—/——/—
    Ampicillin2–>6464>644.3/87.7—/95.7
    Amoxicillin-clavulanate1–>6464643.2/94.1—/96.8
    Ceftazidime≤1–>16≤1>1677.9/21.371.9/22.1
    Cefepime≤1–>32≤1295.3/4.085.0/5.1
    Piperacillin-tazobactam1–>128412879.8/12.676.7/20.2
    Imipenem0.12–41191.3/0.499.6/0.0
    Levofloxacin≤0.5–>16≤0.5292.1/6.788.5/7.9
    Gentamicin≤0.5–>161192.1/7.991.7/7.9
    Tigecycline0.25–40.5198.0/0.095.3/2.0
    Polymyxin B≤0.25–40.5198.8/1.2—/—
Proteus mirabilis (250)
    AN33650.5–211—/——/—
    Ampicillin0.5–>642>6470.0/30.0—/30.0
    Amoxicillin-clavulanate0.5–>641890.8/3.6—/9.2
    Ceftazidime≤1–>16≤1≤198.4/1.296.0/1.6
    Cefepime≤1–>32≤1≤195.6/4.093.6/4.4
    Piperacillin-tazobactam0.12–80.51100.0/0.0100.0/0.0
    Imipenem0.06–42430.8/14.485.6/0.0
    Levofloxacin≤0.5–>16≤0.51678.4/17.271.2/21.6
    Gentamicin≤0.5–>1611686.8/10.483.2/13.2
    Tigecycline0.5–82462.0/3.616.8/38.0
    Polymyxin B>8>8>80.0/100.0—/—
Indole-positive Proteeaed (259)
    AN33650.25–40.51—/——/—
    Ampicillin0.5–>64>64>645.8/92.3—/94.2
    Amoxicillin-clavulanate0.5–>64>64>6417.4/81.1—/82.6
    Ceftazidime≤1–>16≤1886.9/8.175.3/13.1
    Cefepime≤1–>32≤1292.7/6.290.0/8.9
    Piperacillin-tazobactam≤0.06–>1280.5498.5/0.897.3/1.5
    Imipenem0.5–82424.7/35.964.1/0.0
    Levofloxacin≤0.5–>16≤0.5>1673.4/22.470.7/26.6
    Gentamicin≤0.5–>161>1679.2/17.473.7/20.8
    Tigecycline0.25–81488.8/0.860.2/11.2
    Polymyxin B0.5–>8>8>80.8/99.2—/—
Serratia marcescens (252)
    AN33650.25–20.50.5—/——/—
    Ampicillin8–>64>64>641.2/97.6—/98.8
    Amoxicillin-clavulanate2–>64>64>641.2/98.4—/98.8
    Ceftazidime≤1–>16≤11689.3/10.386.1/10.7
    Cefepime≤1–>32≤1299.2/0.890.9/2.4
    Piperacillin-tazobactam0.5–12821690.5/2.484.1/9.5
    Imipenem0.25–640.5194.8/0.899.2/0.4
    Levofloxacin≤0.5–>16≤0.5293.3/3.284.9/6.7
    Gentamicin≤0.5–>161292.1/7.191.3/7.9
    Tigecycline0.25–81297.6/0.479.7/2.4
    Polymyxin B0.5–>8>8>86.7/93.3—/—
  • a Criteria for susceptibility for comparators as published by the Clinical and Laboratory Standards Institute (34), except for tigecycline, where the FDA approved breakpoints were applied (35).

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

  • c —, breakpoint not available.

  • d Includes Morganella morganii (150 strains), P. vulgaris (41 strains), Providencia rettgeri (14 strains), Providencia stuartii (43 strains), and Providencia spp. (11 strains).