1507. Pharmacodynamic Target Attainment of Daptomycin Against Staphylococcus aureus for Treatment of Pediatric Osteomyelitis

Background Daptomycin (DAP) is lipopeptide that frequently is used to treat infections caused by Staphylococcus aureus in adult patients. There are limited data using daptomycin in pediatric patients for the treatment of osteomyelitis caused by S. aureus. This study’s objective is to describe pharmacodynamic (PD) target attainment of daptomycin in pediatric patients with osteomyelitis. Methods Medline was queried to obtain PD targets, pediatric pharmacokinetic models, and bone penetration information to build a model for DAP. A 10,000 subject Monte Carlo simulation was performed to estimate steady-state concentrations in the bone. Simulations modeled 30-minute infusions with using 12 mg/kg/dose IV q24h for patients less than 7 years and 10 mg/kg/dose IV q24h for patients 7 years and older. Goal PD targets were: AUC24: MIC of 666 μg hours/mL for log1 killing and AUC24: MIC of 1,061 for log2 killing. The CLSI breakpoint of 1 mg/L was used as a starting point and MIC’s were analyzed below that level. Results PD target attainment in percentages is listed for DAP below in Tables 1 and 2 and are separated by age groups of patients. Conclusion The studied DAP doses did not reach any PD target attainment at the CLSI breakpoint of 1 mg/L. Based on these data, DAP should not be empirically used to treat SA osteomyelitis unless the exact MIC is known. Furthermore, modern pediatric pharmacokinetic studies of DAP for pediatric osteomyelitis are warranted. Disclosures All authors: No reported disclosures.