Inclusion Criteria:

• Written parental (or appropriate legal representative) informed consent prior to any study-related procedure not part of normal medical care;
• Male or female between the ages of 2 and 6 years old, inclusive;
• Able to comply with the protocol for the duration of the study;
• Clinically stable with no evidence of hemodynamic instability (defined as a requirement for pharmacological intervention to manage blood pressure) in the 72 hour window prior to enrollment, and no history or evidence of renal or hepatic compromise;
• Suspected or diagnosed Gram-positive infection for which the subject is receiving standard antibiotic therapy;
• A calculated creatinine clearance rate (CLcr) ≥ 80 ml/min/1.73m2 as determined by the Schwartz equation at baseline;
• Creatine phosphokinase (CPK) levels less than 2X ULN (upper limit of normal) at baseline.
• Presence of two patent intravenous lines (or comparable means of venous access) prior to dosing on Study Day 1.

Exclusion Criteria:

• Investigational drug use (including daptomycin) or participation in any experimental procedure in the 30 days preceding study entry;
• Known allergy/ hypersensitivity to daptomycin;
• History of clinically significant cardiovascular, renal, hepatic, pulmonary (well-controlled asthma is acceptable), gastrointestinal, endocrine, hematologic, autoimmune disease or primary immune deficiency;
• Pneumonia as sole Gram-positive infection being treated with standard antibiotics;
• Subjects with clinically significant abnormal laboratory test results [including electrocardiograms (ECGs)], as determined by Investigator;
• Administration of rifampin within 7 days of study drug administration;
• Body mass index (BMI) that is outside of the 5th to 95th percentile;
• Subjects in whom collection of the required blood volume would put them at risk of hemodynamic disturbance (at the discretion of Investigator);
• History of or current clinically significant (at the discretion of the Investigator) muscular disease, nervous system or seizure disorder;
• Administration of intramuscular injection between baseline and study drug administration or expected intramuscular injection within 24 hours following dosing;
• Expected surgical procedure(s) within 24 hours prior to and following dosing;
• Unexplained muscular weakness, history of peripheral neuropathy, Guillian-Barre or spinal cord injury;
• History of or current rhabdomyolysis.