This is a Phase 1, multicenter, open-label, PK, safety and tolerability study of oritavancin in pediatric patients (<18 years of age) with suspected or confirmed Gram-positive bacterial infections. Approximately 48 patients will be enrolled at 10-15 US centers. This study will include 5 age cohorts and patients will be entered in a stepwise approach starting with the older age cohort (12-<18 years). The starting dose will be IV oritavancin 15 mg/kg. The safety, tolerability and PK data will be reviewed at the completion of each cohort to ensure safety and determine the appropriate dose for the next age cohort. At least 8 patients will be enrolled in each cohort except for the birth to <3 month age cohort which will have at least 16 patients enrolled. Seven PK samples will be collected over 14 days. The safety follow-up will complete with a 60-day phone call to the caregiver.