This multicenter, study will be run into two parts. Both parts will be run in consecutive age cohorts, starting from the oldest age categories(12 to \< 18 years old) to the youngest (birth to \< 3 months).
* Part A is an open-label, dose finding part to be conducted in at least 24 subjects.
* Part B follows a randomized, assessor-blinded, parallel-group design with vancomycin used as an active comparator. Part B will be conducted in about 176 children.
In both parts, the treatment period will be 10 days and will be followed by a Follow-up period of 28-32 days.
