Although early transition from intravenous to oral antimicrobials can reduce hospitalization duration, susceptibility breakpoints have not been established for many oral antimicrobials against Escherichia coli and Klebsiella pneumoniae bacteremia. Thus, we used population pharmacokinetic models, pharmacokinetic/pharmacodynamic indices, and Monte Carlo simulations to evaluate the probability of target attainment (PTA) for common oral antimicrobial dosages against E. coli and K. pneumoniae. The oral antimicrobial agents evaluated included cephalexin, cefaclor, cefditoren, amoxicillin/clavulanic acid, faropenem, and levofloxacin. For E. coli, the percentage of isolates with minimum inhibitory concentrations for which a PTA >90% was achieved was 53% and less than 20% for levofloxacin and the β-lactams, respectively. For K. pneumoniae, the percentages of isolates for which a PTA >90% was achieved were comparatively higher (cephalexin, 73%; amoxicillin/clavulanic acid, 83%; levofloxacin, 96%). Our results suggest clinicians should check if pharmacokinetic/pharmacodynamic indices are achieved in individual patients before transitioning to oral antimicrobial therapy.
Keywords: Escherichia coli; Klebsiella pneumoniae; oral antimicrobials; pharmacodynamics; pharmacokinetics.
Copyright © 2022 Elsevier Inc. All rights reserved.