Clinical Characteristics And Risk Factors Of Severe Chlamydia Psittaci Pneumonia Based On MNGS Diagnosis

Objective:To analyze the clinical characteristics of Chlamydia psittaci pneumonia(C.psittaci pneumonia)and explore the risk factors of severe C.psittaci pneumonia.To improve the clinician’s understanding of the disease,diagnosis and treatment level,improve the prognosis of patients.Methods:Retrospective analysis of clinical data of 65 patients diagnosed with C.psittaci pneumonia through metagenomic next generation sequencing(m NGS)admitted to the First Affiliated Hospital of Nanchang University between December 2019 and September 2022,describe the clinical characteristics of the patient.According to the severity of the disease,the patients were divided into severe pneumonia group and non-severe pneumonia group.The general data,clinical manifestations,laboratory examinations,imaging indicators,treatment and outcome of the two groups of patients were compared,and univariate analysis was performed first.Multivariate Logistic regression analysis was performed on the indicators with statistically significant differences in univariate analysis,to explore the independent risk factors for severe C.psittaci pneumonia,and receiver operating characteristic(ROC)curve was plotted to evaluate the predictive efficacy of each indicator for severe pneumonia.Results:A total of 65 patients with C.psittaci pneumonia were included in this study,with an average age of 58 years,53.5%of patients were female,and more cases occurred in autumn or winter.Typical clinical manifestations were fever,cough,fatigue,chest tightness,dizziness,etc.Laboratory examination showed that most patients had normal white blood cell counts,decreased lymphocytes,and elevated inflammatory markers such as CRP,LDH,and PCT.Some patients have abnormal liver function,hypoproteinemia and electrolyte disturbance.A small number of patients showed abnormal renal function,abnormal myocardial enzyme profile and thrombocytopenia.The pulmonary imaging findings were mostly ground glass shadow,some solid shadow and air bronchial sign.The lesion often involves multiple lobes.Most patients are sensitive to tetracycline,macrolides and fluoroquinolones.The overall prognosis was good.63 patients were discharged after improvement,one patient returned to the local hospital for further treatment,and one patient died.The overall mortality rate was 1.5%.Univariate analysis suggested that LY,PLT,ALB,NLR,PCT,ALT,AST,LDH,Scr,BUN,CK,CK-MB,D-D,lesion range and respiratory support were significantly different between the severe pneumonia group and the non-severe pneumonia group.Multivariate logistic regression analysis indicated that PLT(OR=1.011,95%CI:1.000-1.022;P=0.044),ALB(OR=1.385,95%CI:1.098-1.746;P=0.006),BUN(OR=0.499,95%CI:0.298-0.835;P=0.008)has guiding significance in predicting the development of severe pneumonia.The optimal cut-off points of PLT,ALB and BUN for predicting severe pneumonia were 134.5x10~9/L,31.25g/L,6.84mmol/L,and AUC were 0.754,0.770,0.779,respectively.The sensitivity,specificity and AUC of PLT,ALB and BUN combined to predict severe pneumonia were the highest,which were 88%,80%and 91.2%,respectively.Conclusion:C.psittaci pneumonia occurs mostly in autumn and winter,mainly manifested as high fever,cough,and elevation of multiple inflammatory markers.Lung imaging findings are mostly lobular pneumonia,and early clear diagnosis and sensitive antibiotic treatment has a better prognosis.Abnormal PLT,ALB and BUN are independent risk factors for severe C.psittaci pneumonia,and their combination can better predict the disease severity of C.psittaci pneumonia.