In this proposal the investigator outline a series of projects to compare oral antibiotics vs. intravenous antibiotics delivered via a PICC line in children who require prolonged (at least 1 week) home antibiotic therapy after hospitalization for three different serious bacterial infections: ruptured appendicitis, complicated pneumonia, and osteomyelitis. To see whether oral antibiotics are just as good as PICC lines, the investigators will use data collected from over 15,000 children with one of these three infections who were hospitalized at one of 43 US children's hospitals during the years 2009-2011, and determine whether PICC lines resulted in fewer rehospitalizations for treatment failure than oral therapy.