Eravacycline Combination Therapy for MRAB

The goal of this observational study is to learn about the eravacycline combination therapy in multidrug-resistant acinetobacter gaumannii pneumonia. The main question is to evaluate the the effectiveness and safety. Participants will be given Eravacycline and Polymyxin，or other antibiotcs that the Investigator considered suitable. During the clinical trial, participants will be monitored for blood drug concentrations and drug concentrations in the ELF (Epithelial Lining Fluid。Clinical efficacy rate and microbiological clearance rate will be assessed at the same time