- Known antibiotic therapy for 48 hours or more prior to admission. Clinically, these children would be considered for a change of treatment to second line antibiotics on admission. Evidence of antibiotic use include any of the following: a) parental report that an antibiotics has been given; b) parent can provide evidence for prescription for antibiotics or c) has the container with antibiotic or d) recognizes medication when shown appropriate containers for locally available antibiotics. Children that have received antibiotics for less than 48 hours prior to admission will be accepted in the trial.