The investigators will collect the blood samples at 0, 2, 4, 6, and 8 h after the first time and the steady state(5 times) of administration from the patients receive treatment with Ceftazidime-Avibactam to detect plasma drug concentrations of ceftazidime avibactam.The collected specimens will be stored in a refrigerator at 0-8 °C, centrifuges within 24 hours (4 °C, 4000 r/min, 10 min), and the supernatant will be collected in an EP tube and stored in a -80 °C refrigerator. Ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS/MS) will be used to detect plasma drug concentrations of ceftazidime avibactam. According to the outcomes ,the investigators will analyse the follwing items,(1)T>MIC,(2)Cmax/MIC,(3)AUC/MIC.
A observational study is conducting at the First Affiliated Hospital of the Medical College of Zhejiang University from January 1, 2022 to September 30, 2022. Patients with severe sepsis and treatment with Ceftazidime-Avibactam will be enrolled.~Blood samples at 0, 2, 4, 6, and 8 h after the first time and the steady state(5 times) of administration will be collected to detect plasma drug concentrations of ceftazidime avibactam.