[Rapid and accurate diagnosis of severe pneumonia: similarities and differences between severe community-acquired pneumonia and hospital-acquired pneumonia/ventilator-associated pneumonia].

(listed in descending order of frequency). In contrast, HAP/VAP cases in China are predominantly bacterial, with Gram-negative bacilli accounting for the majority of isolates. The antimicrobial resistance profiles of SCAP and HAP/VAP pathogens are markedly distinct: HAP/VAP pathogens exhibit substantially higher resistance rates than their CAP counterparts, necessitating different therapeutic approaches. In terms of severity assessment criteria, SCAP has well-established severity stratification systems, whereas HAP/VAP currently lacks standardized diagnostic criteria for severe cases. This discrepancy may lead to reduced inter-rater reliability and diagnostic accuracy when evaluating clinical severity compared to CAP. For etiological diagnosis, SCAP and HAP/VAP require distinct diagnostic approaches. Culture combined with antimicrobial susceptibility testing (AST) plays a pivotal role in HAP/VAP diagnosis. Proper lower respiratory tract specimens are a prerequisite for accurate identification. In contrast, most SCAP pathogens are difficult to culture; therefore, rapid and sensitive molecular detection methods, such as polymerase chain reaction (PCR) and next-generation sequencing (NGS), are essential for SCAP pathogen identification. Clinicians should develop a rapid and precise diagnostic approach for pneumonia management, applying distinct strategies for SCAP versus HAP/VAP. While initiating appropriate empirical therapy, active identification of causative pathogens through advanced diagnostics should be pursued in order to achieve the goals of precision medicine and ultimately improve patient outcomes.