Introduction Staphylococcus aureus is the main causative agent of bone and joint infections (BJI). More than 80% of the strains isolated in France are methicillin-susceptible (MSSA). During the early phase of MSSA BJI management national and international guidelines recommend the use of intra-venous type M penicillin with a dosage ranging from 100 to 200 mg/kg/day. Pharmacological properties of this class of penicillin require 4 to 6 infusions by day. Continuous infusion of beta-lactams is increasingly used especially in intensive care units. It allows an improvement of pharmacokinetic/pharmacodynamics (PK/PD) parameters and a reduction in time dedicated to infusion preparations by the nurses. However pharmacological data regarding such administration is required for type M penicillin.~Design A 6-day, prospective, randomized, open-label, monocentric crossover study~Participants Twelve adult patients with MSSA BJI~Intervention Patients will be randomized in two groups: the first group will receive 3 days of cloxacillin (150 mg/kg/day) through 4 intermittent infusions/day followed by 3 days of cloxacillin (150 mg/kg/day) through continuous infusion (2 infusions during 12 hours). In the second group the infusion modalities will be inverted and continuous infusion will be preceded by a loading dose. Serum concentrations of cloxacillin will be determined at Day 3 and Days 6 The area under the curve / minimal inhibitory concentration ratio will be use to establish the equivalence between both administration modalities.
Our objective is to establish pharmacological equivalence of intermittent and continuous infusion of cloxacillin during methicillin-susceptible Staphylococcus aureus (MSSA) bone and joint infections (BJI). Twelve patients suffering MSSA BJI will receive both administration modalities and serum concentrations of cloxacillin will be determined after 3 days of II and 3 days of continuous infusion in a prospective, randomized, open-label, monocentric crossover study design.