PK/PD of Ceftazidime Avitbatan Sodium in Children With Severe Infection

For 6-18 years children, 62.5 mg/kg/once，q8h ; 3-6 months of age 50 mg/kg/ once,q8h, intravenous administration for 2 hours, daily dose is not more than 2.5g, children will be administrated at least five times.