Objectives: Community-acquired pneumonia (CAP) was a common respiratory tract infection in children, which can be caused by various pathogens, including bacteria, mycoplasma (MP), respiratory syncytial virus (RSV), and recently SARS-CoV-2 are the most widespread. We attempt to distinguish common and pathogen-specific host response characteristics by comparing the CAP of different pathogens. Methods: We included 200 CAP hospitalized cohort caused by SARS-CoV-2 (COVID-19, n=50), mycoplasma (CAP-MP, n=50), RSV (CAP-RSV, n=50) and other bacteria (CAP-Bacteria, n=50), of whom were balanced the potentially confounding factors (such as age and gender) based on Propensity Score Matching algorithm(PSM). We compared hematologic and biochemical indicators for different CAPs, samples were taken within 48 hours of admission. Results: Main clinical features of COVID-19 were fever, faster heart rate and lower antibiotic use. Notably, markers of immuno-inflammatory, including white blood cell, lymphocyte and procalcitonin (PCT) were not different among the CAP groups. Biomarkers reflecting nutrient metabolism showed total protein (TP) and albumin (ALB) levels in the COVID-19 group were lower than those in the CAP-MP group, the creatinine and urea levels of the COVID-19 patients were higher than that of CAP-MP group. The serum sodium and calcium levels in the COVID-19 group were the lowest and significantly lower than that in the CAP-MP group, while serum phosphorus levels were opposite. Moreover, we observed that the creatine kinase (CK) and creatine kinase-MB (CK-MB) levels in the COVID-19 were higher than those in the CAP-MP groups. Conclusions: Our study revealed common and unique pathophysiological features of different pathogens‐associated CAP, which may facilitate the pathogen-specific precision diagnosis and treatment.

Background:Invasive mechanical ventilation is a crucial intervention for the management of critical COVID-19 patients. However, the impact of prone position (PP) on patients undergoing invasive mechanical ventilation remains uncertain. This study aims to investigate the potential benefits of PP in terms of improving the oxygenation index and prognosis. Methods:A total of 289 critically ill COVID-19 patients were retrospectively gathered from ICU of three general hospitals located in Taizhou, Zhejiang Province from December 1, 2022 to February 1, 2023, all patients were invasive mechanical ventilated. 78 cases of PP group and 78 cases of non-PP group were matched with propensity score matching. The study compared clinical data, laboratory results, and hospitalization survival rate between two groups of patients. Furthermore, we compared the laboratory results, and hospitalization survival across varying numbers of PPs. Results:The mean oxygenation index exhibited a greater increase in PP group compared to non-PP group (48 vs 32mmHg). Hospital survivors of PP group (63 patients) demonstrated more substantial decrease in their Sequential Organ Failure Assessment scores and C-reactive protein levels compared to non-PP group (51 patients). The initial PP cycle resulted in a significant elevation of the oxygenation index by 30.8 (-16.4,46.9) mmHg; the second PP cycle demonstrated a maximum increase of 56.3 (13.0,92.8) mmHg. A higher frequency of PP yielded a more pronounced improvement in oxygenation and had the potential to enhance the survival rate. Additionally, the eight patients who was improvements in their oxygenation index during the initial three PP cycles and successfully survived had higher lymphocyte counts (0.2-2.4) vs (0.1-0.5)×10 9/L and a longer duration of PP (53.0-113.5) vs (36.0-98.5)h. Conclusion:PP has the potential to enhance the oxygenation index and survival rates among critically ill COVID-19 patients invasive mechanical ventilated. Notably, a positive correlation was observed between the frequency of PP and the improvement of oxygenation. Our investigation further revealed that the efficacy of the PP may be influenced by lymphocyte count and duration of PP.