Omadacycline for the Treatment of Severe Pneumonia Caused by Chlamydia psittaci Complicated with Acute Respiratory Distress Syndrome during the COVID-19 pandemic.

Severe Chlamydia psittaci pneumonia can lead to acute respiratory distress syndrome (ARDS), septic shock, or multiple organ dysfunction with a mortality rate of 15-20% before accurate diagnosis and targeted treatment. Sixteen patients with severe psittacosis pneumonia with ARDS were selected between September 2021 and October 2022. They were diagnosed using mNGS and treated with omadacycline. Common symptoms included fever, dyspnea and cough. All patients developed ARDS, accompanied by septic shock(43.7%) and pulmonary embolism (43.7%). Laboratory data showed normal leucocytes, increased creatine kinaseisoenzyme and decreased albumin with liver dysfunction in most patients. All patients had increased neutrophils, C-reactive protein, procalcitonin and D-dimer with decreased lymphocytes. Airspace consolidation, ground glass opacity and pleural effusion were found on chest CT. All patients received mechanical ventilation with omadacycline treatment. Fourteen patients experienced complete recovery, while the other two patients died from multidrug-resistant bacterial infection and renal failure. Timely treatment of omadacycline can improve prognosis and provide a promising new option for the treatment of severe Chlamydia psittaci pneumonia with ARDS.