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

Abstract

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.

Clinical and chest computed tomography features associated with severe Chlamydia psittaci pneumonia diagnosed by metagenomic next-generation sequencing: A multicenter, retrospective, observational study

“…Previous studies on psittacosis pneumonia have reported inconsistent results owing to the small number of patients and lack of separate analysis of drug treatment for mild and severe patients. [5,15,29,31] In this study, most patients received quinolones before diagnosis, of which some non-severe patients showed a good response to treatment, whereas severe patients showed a poor response. Therefore, using quinolones alone is not recommended in severe patients.…”

“…C psittaci is transmitted after the inhalation of aerosolized bacterial cells, [10,11] which can rapidly cause severe respiratory failure and even death. [5,12] High-risk factors for infection include old age, smoking, male sex, glucocorticoid use, and long-term residence in nursing homes. The prognosis of patients is directly associated with immunity.…”

“…[4] In recent years, clinical reports of psittacosis pneumonia diagnosed using mNGS have increased. [5] However, the number of reported cases is small, most of which have been descriptive, [5] and a few systematic analyses of the clinical features of severe and non-severe patients have been conducted. The aim of this study was to investigate the clinical and chest computed tomography (CT) features of severe psittacosis pneumonia.…”

Primary Sjögren’s syndrome combined with Chlamydia psittaci infection

“…Psittacosis is a zoonotic disease caused by Chlamydia psittaci [3,4]. Patients infected with Chlamydia psittaci have infiltration and exudation of inflammatory cells in the alveoli, resulting in significant thickening of the alveolar wall and interstitial lung mass, edema, and necrosis [5].…”