Aerosolized Plus Intravenous vs. Intravenous Colistin for VAP Due to Pandrugs-resistant A. Baumannii in Neonates

Inclusion Criteria: * Neonates who are admitted to the neonatal intensive care unit, Hat Yai Hospital during the study period. * Neonates who were complicated with VAP due to PDR-Acinetobacter baumannii susceptible to colistin (by minimal inhibitory concentration (MIC) \< 2 mcg/dL). Exclusion Criteria: * Neonates who have a major anomaly or chromosomal abnormality. * Neonates who receive colistin prior 7 days prior to study. * Neonates who have a significant renal dysfunction defined as a serum creatinine (SCr) \>1.5 mg/dL or a decrease in urine output to \< 1 mL/kg/h;