Substantial impact of altered pharmacokinetics in critically Ill patients on the antibacterial effects of meropenem evaluated via the dynamic hollow-fiber infection model

Phillip J Bergen, Jurgen B Bulitta, Carl M J Kirkpatrick, Kate E Rogers, Megan J. McGregor, Steven C Wallis, David L Paterson, Roger L Nation, Jeffrey Lipman, Jason A Roberts, Cornelia B Landersdorfer

Research output: Contribution to journalArticleResearchpeer-review

14 Citations (Scopus)

Abstract

Critically ill patients frequently have substantially altered pharmacokinetics compared to non-critically ill patients. We investigated the impact of pharmacokinetic alterations on bacterial killing and resistance for commonly used meropenem dosing regimens. A Pseudomonas aeruginosa isolate (MICmeropenem 0.25 mg/ liter) was studied in the hollow-fiber infection model (inoculum ∼107.5 CFU/ml; 10 days). Pharmacokinetic profiles representing critically ill patients with augmented renal clearance (ARC), normal, or impaired renal function (creatinine clearances of 285, 120, or ∼10 ml/min, respectively) were generated for three meropenem regimens (2, 1, and 0.5 g administered as 8-hourly 30-min infusions), plus 1 g given 12 hourly with impaired renal function. The time course of total and less-susceptible populations and MICs were determined. Mechanism-based modeling (MBM) was performed using S-ADAPT. All dosing regimens across all renal functions produced similar initial bacterial killing (≤∼2.5 log10). For all regimens subjected to ARC, regrowth occurred after 7 h. For normal and impaired renal function, bacterial killing continued until 23 to 47 h; regrowth then occurred with 0.5-and 1-g regimens with normal renal function (fT<5×MIC = 56 and 69%, fCmin/MIC ≥ 2); the emergence of less-susceptible populations (≥32-fold increases in MIC) accompanied all regrowth. Bacterial counts remained suppressed across 10 days with normal (2-g 8-hourly regimen) and impaired (all regimens) renal function (fT<;5×MIC ≥ 82%, fCmin/MIC ≥ 2). The MBM successfully described bacterial killing and regrowth for all renal functions and regimens simultaneously. Optimized dosing regimens, including extended infusions and/or combinations, supported by MBM and Monte Carlo simulations, should be evaluated in the context of ARC to maximize bacterial killing and suppress resistance emergence.

Original languageEnglish
Article numbere02642
Number of pages14
JournalAntimicrobial Agents and Chemotherapy
Volume61
Issue number5
DOIs
Publication statusPublished - 1 May 2017

Keywords

  • Augmented renal clearance
  • Critically ill
  • Pharmacodynamic modeling
  • Pharmacokinetics

Cite this