Safety and efficacy of linezolid in 16 infants and children in Japan.

Linezolid, an oxazolidinone antibiotic, exhibits a broad spectrum of activity against Gram-positive bacteria. It has been licensed for adult use in Japan since 2006 for MRSA infections, and has also been used off-label for pediatric patients. At our university hospital, a total of 16 infants and children (including one non-Japanese Asian) were administered linezolid owing to infection with multidrug-resistant Gram-positive bacteria, after consent had been provided. All patients had severe underlying diseases or indications for surgery. Eighty-eight percent of the causal microorganisms were methicillin-resistant Staphylococcus aureus (MRSA) or methicillin-resistant coagulase-negative Staphylococcus and all were sensitive to linezolid. Linezolid was administered because the antecedent anti-MRSA medications were ineffective or contraindicated, or intravenous-to-oral switch therapy was requested owing to cardiac or orthopedic surgical-site infections. The median duration of administration was 13 days (range 3-31 days). The overall efficacy was 91 % (10/11) in those for whom efficacy could be evaluated. Only two patients (both teen-aged) encountered linezolid-related adverse effects (13 %, 2/16). One patient showed elevation of liver enzymes (aspartate aminotransferase [AST] and alanine aminotransferase [ALT]), requiring that administration be withdrawn, but enzyme levels returned to normal after the patient had been switched to vancomycin. The other patient showed transiently decreased platelet counts. Linezolid is considered generally safe and effective for children in Japan, especially for those who cannot use other anti-MRSA medications or those who require oral antibiotics for infections with multidrug-resistant Gram-positive bacteria.