The purpose of this study is to determine the value of M-ROSE（microbiological rapid on-site evaluation）in severe hospital-acquired pneumonia.

Severe hospital acquired pneumonia (SHAP) is the critical risk factor leading to the death of nosocomial infection patients. Rapid identification of pathogens, guidance of individualized treatment and rational application of antibiotics can not only improve the administration of antibiotics, but also reduce the production of multi drug resistant bacteria. Metagenomic second-generation sequencing (mNGS) is an important tool to quickly identify the pathogen in ICU. However, due to the low qualified rate of lower respiratory tract specimens in patients with SHAP, easily polluted, and the difficulty to determine whether microorganisms are infectious, colonizated or polluted, the value of mNGS was limited in the etiological diagnosis of SHAP. The bedside M-ROSE system established by our research team can determine whether the lower respiratory tract specimen is qualified, whether infection exists and the pathogen of infection within half an hour. Based on the previous work, this project plans to conduct a prospective multicenter, single blind, randomized controlled study under the guidance of M-ROSE and mNGS in the individualized anti-infection strategy of SHAP, to reduce the mortality of patients with SHAP; Combined with the third-generation sequencing, the standard analysis framework for the traceability and prevention and control of drug-resistant bacteria was established to clarify the transmission route of drug-resistant bacteria, so as to provide a new solution for the prevention and control of clinical multidrug-resistant bacteria.

Inclusion Criteria:

• Clinical diagnosis of severe hospital-acquired pneumonia
• Must have undergone bronchoalveolar lavage

Exclusion Criteria:

• BALF samples were not sent for mNGS examination
• Age < 18 years old
• The hospitalization days ≤ 3
• The clinical data are incomplete
• Mechanical ventilation time > 60 days