Determination of the pharmacokinetic-pharmacodynamic cut-off values of marbofloxacin in horses to support the establishment of a clinical breakpoint for antimicrobial susceptibility testing.

Background: Marbofloxacin (MBX), a fluoroquinolone (FQ), is considered as a critical antibiotic requiring antimicrobial susceptibility testing (AST) for prudent use. No clinical breakpoint (CBP) currently exists to interpret the results of such tests in horses.

Objectives: To compute PK/PD cut-offs (PK/PD ) that is one of the three minimum inhibitory concentrations (MICs) considered establishing a CBP for antimicrobial susceptibility test interpretation.

Comparison of in vitro static and dynamic assays to evaluate the efficacy of an antimicrobial drug combination against Staphylococcus aureus.

An easily implementable strategy to reduce treatment failures in severe bacterial infections is to combine already available antibiotics. However, most in vitro combination assays are performed by exposing standard bacterial inocula to constant concentrations of antibiotics over less than 24h, which can be poorly representative of clinical situations. The aim of this study was to assess the ability of static and dynamic in vitro Time-Kill Studies (TKS) to identify the potential benefits of an antibiotic combination (here, amikacin and vancomycin) on two different inoculum sizes of two S.

Differential Activity of the Combination of Vancomycin and Amikacin on Planktonic vs. Biofilm-Growing Bacteria in a Hollow Fiber Infection Model.

Combining currently available antibiotics to optimize their use is a promising strategy to reduce treatment failures against biofilm-associated infections. Nevertheless, most assays of such combinations have been performed on planktonic bacteria exposed to constant concentrations of antibiotics over only 24 h and the synergistic effects obtained under these conditions do not necessarily predict the behavior of chronic clinical infections associated with biofilms. To improve the predictivity of combination assays for bacterial biofilms, we first adapted a previously described Hollow-fiber (HF) infection model by allowing a biofilm to form before drug exposure.