Relationship Between Nasopharyngeal Chlamydia Trachomatis Copies And Severe Chlamydia Trachomatis Pneumonia

Objective:To analyze the clinical characteristics of severe chlamydia trachomatis pneumonia in infants,and to explore the relationship between nasopharyngeal Chlamydia trachomatis copies and severe chlamydia trachomatis pneumonia.Methods:We conducted a retrospective study in our hospital.The clinical data of 192 patients with chlamydia trachomatis pneumonia was analyzed retrospectively.They were divided into common group and severe group according to the guidelines for the management of community-acquired pneumonia in children(revised version 2013).We compared and analyzed the clinical characteristics of two groups,and A ROC curve was employed to investigate the diagnostic value of CT-DNA copies in severe chlamydia trachomatis pneumonia.Results:Of the 192 children,136 were common cases and 56 were severe cases.Compared with the common group,the onset age was younger in severe group(39.5d vs 47d,P<0.001),the proportion of natural labor was higher(100%vs 90.4%,P=0.012),and the hospitalization days were longer(8d vs 6d,P<0.001),WBC count(16.17±5.47×10~9/L vs 13.96±3.95×10~9/L,P=0.002)、eosinophil count(0.68×10~9/L vs 0.56×10~9/L,p=0.02)、PCT level(0.16ng/L vs 0.11ng/L,P=0.002)was also higher,the proportion of tachypnea(96.4%vs 55.1%,p<0.001),patients with conjunctivitis(30.4%vs 9.6%,P<0.001),dense fine wet rales(41.1%vs9.6%,P<0.001)were higher,CT-DNA copies were higher(6.194×10~7copies/m L vs 1.77×10~7copies/m L,P<0.001),albumin was lower(39.1g/L vs 40.1g/L,P=0.006).There is no statistical difference in gender,birth weight,fever,wheezing ratio and CRP、PLT、ALT、AST、LDH level between two groups.Chest CT in severe cases mostly showed uneven inflation,segmental consolidation and diffuse interparenchymal lesions.The optimal point of CT-DNA copies was 3.71×10~7copies/m L with73.2%sensitivity and 61.8%specificity(AUC:0.673,95%CI:0.594-0.751).According to the cut-off value of 3.71×10~7copies/m L,192 cases were divided into low copy level group(including 84 common cases and 15severe cases)and high copy level group(including 52 common cases and41 severe cases).The chi-square test showed that high copy level group was more prone to severe infection(P<0.001).Logistic regression analysis showed that tachypnea(OR=18.061,95%CI:3.709-87.962),dense fine wet rales(OR=4.625,95%CI:1.705-12.547),high CT-DNA copies(OR=3.969,95%CI:1.664-9.468)were independent risk factors for severe chlamydia trachomatis pneumonia,age(OR=0.966,95%CI:0.936-0.998)is a protective factor.Conclusion:Compared with the common group,severe chlamydia trachomatis pneumonia in infants often starts earlier,has higher WBC count、eosinophil count、PCT level and higher CT-DNA copies,and the high CT-DNA copies have certain predictive value for severe chlamydia trachomatis pneumonia.