2.6 Outcome assessment
Microbiological success was chosen as the major outcome in our study. We defined microbiological success as a ≥103 cfu/mL quantitative culture decrease in bacterial count three days after the initial treatment. The clinical outcomes were evaluated by investigators on days 5, 14, and 28. A clinical success was defined as a decrease in PCT and WBC levels in the first 5 days and the resolution of fever or clinical symptoms. We consider that if clinical outcome was not achieved until day 5, the patient was defined as a clinical failure case. Microbiological success was detected by blood or sputum samples and drug resistance analysis on days 10-14. We also evaluated the 28-day mortality on days 28-30 and the time of stay in the ICU.