Sixteen cases of severe pneumonia caused by Chlamydia psittaci in South China investigated via metagenomic next-generation sequencing

Abstract

Introduction. Chlamydia psittaci is an important cause of community-acquired pneumonia (CAP). The spectrum of CAP due to Chlamydia psittaci ranges from mild, self-limited to acute respiratory failure and the early identification of this disease can be challenging. Metagenomic next-generation sequencing (mNGS) of bronchoalveolar lavage fluid has the potential to improve the pathogen identification in severe CAP. Hypothesis/Gap Statement. Metagenomic next-generation sequencing (mNGS) of bronchoalveolar lavage fluid has the potential to rapidly identify pathogens in severe CAP. The early identification and appropriate use of antibiotics can improve the prognosis of severe CAP caused by Chlamydia psittaci . Aim. The aim of the study is to describe the clinical spectrum of severe psittacosis pneumonia to provide a better understanding of this disease and to demonstrate that mNGS is an effective method for pathogen detection. Methodology. Retrospective case analysis from November 2019 to November 2020 was performed. Sixteen cases of severe psittacosis pneumonia were diagnosed through mNGS. Clinical features, laboratory findings, imaging features, treatment and outcome were summarized. Results. Frequent symptoms included fever (16/16, 100%), dyspnoea (16/16, 100%), cough (12/16, 75%), sputum (11/16, 69%) and headache (9/16, 56%). The median leukocytosis was within the normal range, while C-reactive proteins, CK, LDH, AST, D-Dimer were significantly elevated. The feature of computed tomography included ground-glass opacity with consolidation and multiple lobar distributions. The total number of sequences of Chlamydia psittaci identified from bronchoalveolar lavage by mNGS varied from 58 to 57115. Five patients underwent noninvasive mechanical ventilation, four patients underwent high flow humidified oxygen therapy and one patient underwent invasive mechanical ventilation. Two patients had septic shock needing vasoactive medications. All of the sixteen patients experienced full recoveries. Conclusion. The symptoms of severe CAP caused by Chlamydia psittaci were not typical while laboratory results may have some clues. The mNGS technology can early detect of psittacosis, reduce unnecessary use of antibiotics and short the course of the disease.

Omadacycline for the Treatment of Severe Chlamydia psittaci Pneumonia Complicated with Multiple Organ Failure: A Case Report

“…Chest imaging indicates predominantly consolidated lung lesions, and respiratory distress and respiratory failure can develop rapidly in most severely ill patients, with some patients presenting ARDS and even multiple organ system failure. 8,9 In the present case, the disease progressed rapidly after onset, and respiratory failure, ARDS, and severe liver and kidney failure developed within a short period. However, the patient had a good prognosis after timely and accurate diagnosis and treatment, suggesting that early and accurate treatment is essential for improving prognosis.…”

Clinical Characteristics of Six Patients with Chlamydia psittaci Infection Diagnosed by Metagenomic Next-Generation Sequencing: A Case Series

“… 16 With the widespread use of mNGS in the clinic, its use to diagnose C. psittaci pneumonia has increased. 8 , 10 , 11 , 17–20 All patients in the present study were diagnosed with C. psittaci infection solely using mNGS. Among the samples that were positive for C. psittaci detected using mNGS, three ompA fragments (1.4 kb) were successfully amplified and sequenced.…”

“…16 With the widespread use of mNGS in the clinic, its use to diagnose C. psittaci pneumonia has increased. 8,10,11,[17][18][19][20] All patients in the present study were diagnosed with C. psittaci https://doi.org/10.2147/IDR.S393195…”

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“…Psittacosis is diagnosed by real-time polymerase chain reaction (RT-PCR) or serology based on clinical suspicions, and many recent studies (8)(9)(10)(11)(12) have reported the use of mNGS on the diagnosis of psittacosis. The mNGS of BALF (5) has the potential to improve pathogen identification in severe pneumonia, and it is widely used in identifying pathogens, especially in severe cases.…”