Clinical Analysis of Metagenomic Next-generation Sequencing Confirmed Chlamydia psittaci Pneumonia: A Case Series and Literature Review

Introduction: Chlamydia psittaci infection is a zoonotic infectious disease, which mainly inhaled through the lungs when exposed to the secretions of poultry that carry pathogenic bacteria. The traditional respiratory specimens or serological antibody testing is slow and the false-negative rate is high. Metagenomic next-generation sequencing gives a promising rapid diagnosis tool. Methods: : We retrospective summarized the clinical characteristics of five C. psittaci pneumonia patients diagnosed by mNGS, conducted a literature review summarizing the clinical characteristics of patients with C. psittaci pneumonia reported since 2010. Results: : Five C. psittaci . pneumonia patients confirmed by mNGS aged from 36 to 66 years with three males. 60% of patients had type 2 diabetes mellitus. And 60% of patients had a history of contact with avian or poultry. All patients had a high fever over 38.5 °C, cough, hypodynamia, hypoxemia, and dyspnea on admission. Two patients had invasive ventilator support and Extracorporeal Membrane Oxygenation support. The levels of C-reactive protein, procalcitonin, and erythrocyte sedimentation rate on admission and follow-up were all higher than normal values. Doxycycline or moxifloxacin monotherapy was accounted for 1/5 (20%) and 2/5 (40%) patients, and combination therapy was accounted for 2/5(40%) patients. Four patients improved and were discharged, and one patient died due to multiple organ failure and disseminated intravascular coagulation. Conclusions: : mNGS can increase the detection rate of C. psittaci , shorten the diagnosis time of C. psittaci pneumonia and improve the prognosis of patients.