TABLE 2

Activities of ceftazidime-avibactam and comparator antimicrobial agents tested against 701 ESBL-phenotype-positive Enterobacteriaceae isolates collected from 72 U.S. hospitals located in the nine U.S. census regions

Isolate group (no. of isolates tested) and antimicrobial agentMIC50 (μg/ml)MIC90 (μg/ml)MIC range (μg/ml)% S/% I/% R according toa:
CLSIEUCAST
KPC producers (118)
    Ceftazidime-avibactam0.520.06–4–/–/––/–/–
    Ceftazidime>32>3216–>320.0/0.0/100.00.0/0.0/100.0
    Ceftriaxone>8>88–>80.0/0.0/100.00.0/0.0/100.0
    Meropenem>8>82–>80.0/4.2/95.84.2/24.6/71.2
    Piperacillin-tazobactam>64>64>640.0/0.0/100.00.0/0.0/100.0
    Levofloxacin>4>4≤0.12–>410.2/1.7/88.15.9/4.3/89.8
    Gentamicin8>8≤1–>847.5/17.8/34.732.2/15.3/52.5
    Tetracycline4>321–>3263.6/15.2/21.2–/–/–
    Tigecyclineb0.510.06–898.3/0.8/0.993.2/5.1/1.7
CTX-M-15-like producers (288)c
    Ceftazidime-avibactam0.120.5≤0.015–2–/–/––/–/–
    Ceftazidime16>320.5–>3214.6/14.2/71.22.8/11.8/85.4
    Ceftriaxone>8>88–>80.0/0.0/100.00.0/0.0/100.0
    Meropenem≤0.06≤0.06≤0.06–299.7/0.3/0.0100.0/0.0/0.0
    Piperacillin-tazobactam16>64≤0.5–>6467.2/17.3/15.548.3/18.9/32.8
    Levofloxacin>4>4≤0.12–>412.5/4.2/83.311.5/1.0/87.5
    Gentamicin2>8≤1–>853.3/2.1/44.651.6/1.7/46.7
    Tetracycline>32>320.5–>3230.2/0.7/69.1–/–/–
    Tigecyclineb0.1210.06–498.3/1.7/0.094.8/3.5/1.7
CTX-M-14-like producers (70)d
    Ceftazidime-avibactam0.120.250.03–1–/–/––/–/–
    Ceftazidime2160.12–>3274.3/11.4/14.335.7/38.5/25.7
    Ceftriaxone>8>8>80.0/0.0/100.00.0/0.0/100.0
    Meropenem≤0.06≤0.06≤0.06–0.25100.0/0.0/0.0100.0/0.0/0.0
    Piperacillin-tazobactam28≤0.5–>6492.9/2.8/4.391.4/1.5/7.1
    Levofloxacin>4>4≤0.12–>417.1/2.9/80.017.1/0.0/82.9
    Gentamicin2>8≤1–>855.7/0.0/44.354.3/1.4/44.3
    Tetracycline>32>320.5–>3222.9/0.0/77.1–/–/–
    Tigecyclineb0.1210.06–494.3/5.7/0.094.3/0.0/5.7
SHV ESBL producers (83)e
    Ceftazidime-avibactam0.120.25≤0.015–0.5–/–/––/–/–
    Ceftazidime>32>321–>3212.0/7.3/80.72.4/9.6/88.0
    Ceftriaxone>8>80.12–>89.6/7.3/83.19.6/7.3/83.1
    Meropenem≤0.060.12≤0.06–298.8/1.2/0.0100.0/0.0/0.0
    Piperacillin-tazobactam>64>641–>6445.8/3.6/50.636.1/9.7/54.2
    Levofloxacin>4>4≤0.12–>439.8/7.2/53.037.3/2.5/60.2
    Gentamicin2>8≤1–>861.4/10.9/27.751.8/9.6/38.6
    Tetracycline4>320.5–>3255.4/9.7/34.9–/–/–
    Tigecyclineb0.510.06–2100.0/0.0/0.094.0/6.0/0.0
CMY-2-like producers (54)f
    Ceftazidime-avibactam0.120.50.03–1–/–/––/–/–
    Ceftazidime16>322–>3213.0/24.0/63.00.0/13.0/87.0
    Ceftriaxone>8>80.5–>81.9/14.8/83.31.9/14.8/83.3
    Meropenem≤0.060.12≤0.06–0.25100.0/0.0/0.0100.0/0.0/0.0
    Piperacillin-tazobactam4>64≤0.5–>6481.5/7.4/11.172.2/9.3/18.5
    Levofloxacin≤0.12>4≤0.12–>470.4/1.8/27.864.8/5.6/29.6
    Gentamicin≤1>8≤1–>879.6/1.9/18.577.8/1.8/20.4
    Tetracycline>32>320.5–>3233.3/1.9/64.8–/–/–
    Tigecyclineb0.1220.06–496.3/3.7/0.085.2/11.1/3.7
ESBL microarray-negative isolates (70)
    Ceftazidime-avibactam0.120.5≤0.015–1–/–/––/–/–
    Ceftazidime140.06–894.3/5.7/0.050.0/44.3/5.7
    Ceftriaxone1>80.12–>855.7/4.3/40.055.7/4.3/40.0
    Meropenem≤0.06≤0.06≤0.06–0.5100.0/0.0/0.0100.0/0.0/0.0
    Piperacillin-tazobactam>64>644–>6430.0/7.1/62.922.9/7.1/70.0
    Levofloxacin≤0.12>4≤0.12–>478.6/0.0/21.475.7/2.9/21.4
    Gentamicin≤12≤1–>892.9/0.0/7.192.9/0.0/7.1
    Tetracycline2>320.5–>3257.1/10.0/32.9–/–/–
    Tigecyclineb0.1210.03–2100.0/0.0/0.095.7/4.3/0.0
  • a Criteria according to the CLSI (15) and EUCAST (16). S, sensitive; I, intermediate; R, resistant. Dashes were used for categories if breakpoint criteria were not available.

  • b U.S. FDA breakpoints were applied (21).

  • c CTX-M-15-like-producing isolates do not include KPC- or NDM-1-producing isolates.

  • d CTX-M-14-like-producing isolates do not include CTX-M-15-like-producing isolates.

  • e SHV ESBL-producing isolates do not include CTX-M-15-like-, CTX-M-14-like-, KPC-, or NDM-1-producing isolates.

  • f CMY-2-like-producing isolates do not include CTX-M-15-like-, CTX-M-14-like-, KPC-, or NDM-1-producing isolates.