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Table 1 Activity of ceftazidime-avibactam and comparator agents against levofloxacin-resistant E. coli; ATLAS, 2012–2018

From: Antimicrobial activity of ceftazidime-avibactam and comparators against levofloxacin-resistant Escherichia coli collected from four geographic regions, 2012–2018

Antimicrobial MIC50
(mg/L)
MIC90 (mg/L) Range
(mg/L)
%S %I %R
ESBL-positive (N = 5749)      
Ceftazidime-avibactam 0.12 0.5  ≤ 0.015– ≥ 256 99.0 1.0
Ceftazidimea 32 128 0.12– ≥ 256 5.3 14.8 79.9
Cefepimea 32 32  ≤ 0.12– ≥ 64 3.0 10.0 86.9
Ampicillin  ≥ 64  ≥ 64 1– ≥ 64 0.2 99.8
Amoxicillin-clavulanatea 16 32  ≤ 0.12– ≥ 64 29.3 70.7
Piperacillin-tazobactam 8 64  ≤ 0.25– ≥ 256 64.8 15.2 20.0
Aztreonama 32 128 0.06– ≥ 256 0.2 8.2 91.6
Imipenem 0.25 0.25  ≤ 0.03– ≥ 16 98.5 0.4 1.1
Meropenem 0.03 0.06  ≤ 0.004– ≥ 32 98.5 0.6 1.0
Colistinb (N = 4470) 0.25 1  ≤ 0.06– ≥ 16 99.1 0.9
Amikacin 4 16 0.5– ≥ 128 83.4 16.6
Tigecycline 0.25 0.5  ≤ 0.015– ≥ 16 95.7 4.3
ESBL-negative (N = 5091)      
Ceftazidime-avibactam 0.12 0.25  ≤ 0.015– ≥ 256 99.6 0.4
Ceftazidime 0.25 4  ≤ 0.015– ≥ 256 88.5 2.3 9.2
Cefepime  ≤ 0.12 1  ≤ 0.12– ≥ 64 91.8 3.8 4.4
Ampicillin  ≥ 64  ≥ 64  ≤ 0.5– ≥ 64 17.4 82.6
Amoxicillin-clavulanate 8 32  ≤ 0.12– ≥ 64 51.4 48.6
Piperacillin-tazobactam 2 64  ≤ 0.12– ≥ 256 81.9 5.0 13.1
Aztreonam 0.12 4  ≤ 0.015– ≥ 256 88.9 2.7 8.3
Imipenem 0.12 0.25  ≤ 0.03– ≥ 16 99.1 0.3 0.6
Meropenem 0.03 0.06  ≤ 0.004– ≥ 32 99.3 0.3 0.4
Colistinb (N = 3864) 0.25 1  ≤ 0.06– ≥ 16 99.0 1.0
Amikacin 2 8  ≤ 0.25– ≥ 128 95.1 4.9
Tigecycline 0.25 0.5  ≤ 0.015–4 94.6 5.4
  1. – Indicates no breakpoint for the agent
  2. ESBL extended-spectrum β-lactamase, %I percentage of isolates susceptible, increased exposure, MIC minimum inhibitory concentration, MIC50 MIC required to inhibit growth of 50% of isolates (mg/L), MIC90 MIC required to inhibit growth of 90% of isolates (mg/L), %R percentage of isolates resistant, %S percentage of isolates susceptible, standard dosing
  3. aNot suitable for use in the treatment of infections caused by ESBL-positive isolates
  4. bColistin was included on the comparator panel from 2014 onwards