Table 3 Antimicrobial agents for the treatment of Enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter baumannii infections in critically ill patients: MIC breakpoints (European Committee of Antimicrobial Susceptibility Testing, guidelines 2015) and first-line daily doses
From: Mechanisms of antimicrobial resistance in Gram-negative bacilli
Antimicrobial agent | MIC breakpoint (mg/L) for susceptibility | Usual daily dosea (intra-venous) | Comment | ||
|---|---|---|---|---|---|
Enterobacteriaceae | P. aeruginosa | A. baumannii | |||
Piperacillin | ≤8 | ≤16 | ND | 4 g/6 h | Consider extended or continuous infusion after a LD |
Piperacillin–tazobactam | ≤8 | ≤16 | ND | 4 g–500 mg/6 h | Consider extended or continuous infusion after a LD |
Aztreonam | ≤1 | ≤1 | IR | 2 g/6–8 h | Consider extended or continuous infusion after a LD |
Ceftazidime | ≤1 | ≤8 | ND | 2 g/6–8 h | Consider extended or continuous infusion after a LD |
Cefepime | ≤1 | ≤8 | ND | 1–2 g/8 h | Consider extended or continuous infusion after a LD High doses for P. aeruginosa infections |
Ertapenem | ≤0.5 | IR | IR | 2 gr/24 h | Once-daily administration |
Meropenem | ≤2 | ≤2 | ≤ 2 | 1–2 g/8 h | Consider extended infusion after a LD |
Imipenem | ≤2 | ≤4 | ≤ 2 | 1 g/6–8 h | No extended infusion (instability) |
Gentamicin | ≤2 | ≤4 | ≤ 4 | 6–8 mg/kg/24 h | Once-daily administration |
Tobramycin | ≤2 | ≤4 | ≤ 4 | 6–8 mg/kg/24 h | Once-daily administration |
Amikacin | ≤8 | ≤8 | ≤ 8 | 25–30 mg/kg/24 h | Once-daily administration |
Ciprofloxacin | ≤0.5 | ≤0.5 | ≤ 1 | 400 mg/8 h |  |
Colistin | ≤2 | ≤4 | ≤ 2 | 4.5 MU/12 h after a LD of 9 MU | Nebulized administration may be considered for VAP |
Tigecycline | ≤1 | IR | ND | 50 mg/12 h after a LD of 100 mg | High-dosing regimen (100 mg/12 h after a LD of 200 mg) has been proposed for severe and/or A. baumannii infections, notably VAP |
Fosfomycin | ≤32 | ND | ND | ND | High doses may be considered (in combination) for extensively drug-resistant Gram-negative bacilli |