Daptomycin is a novel lipopetide antibiotic against gram-positive organisms, including multi-resistant strains. It effectively penetrates bone and has bactericidal activity within biofilms. In adults it has been demonstrated active against Staphylococcus Aureus Methicillin Sensible (MSSA) and Resistant (MRSA) bacteremia. The main side effect is a transitory myopathy that appears to be dose and frequency related. There are limited dates on daptomycin in pediatric patients.

We reviewed the medical records of four children (3 males and 1 female), with a median age of 11.2 years (range 7–13 years), who received daptomycin therapy for a complicated osteomyelitis. Osteomyelitis was clinically suspected and confirmed by magnetic resonance imaging at left ankle, left tibia, left calcaneum, lumbar column.

The pathogen isolated was a MSSA in all four cases. All patients received prior antibiotic treatment. Therapy was swiched to Daptomycin for first line treatment failure (in three cases) and for an adverse reaction to first line treatment (in one case). Daptomycin was prescribed at the mean dosage of 9 mg/kg/day (range 8–10 mg/kg/day) for a median time of 15 days. After 4 days therapy, all patients clinically and laboratory improved with resolution of fever and pain and decreased inflammatory indexes. No patient underwent surgery. After a median of 20 days of hospitalization, patients were discharged with oral antibiotic therapy. They received follow-up clinical evaluation for 8 months (range 6–10 months) with no sequelae.

With the limits of a small population and of a retrospective and unblended study, daptomycin therapy may be useful in complicated osteomyelitis and allowed the avoidance of surgery. The good outcome of the patients was probably due to daptomycin bactericidal activity against bacteria and to its ability to penetrate into bone and synovial fluid. Daptomycin therapy has been well tolerated in all patients, even if administered at a higher dose. No side effect was reported during therapy and at a 30 days follow-up evaluation.