To investigate the clinical manifestations, laboratory findings, imaging features, and treatment outcomes of patients with Chlamydia psittaci pneumonia, aiming to provide references for early clinical identification and precise treatment. A retrospective study was conducted, collecting clinical data from 13 patients diagnosed with Chlamydia psittaci pneumonia via multiple targeted amplification-high-throughput sequencingat the Second Affiliated Hospital of Guilin Medical University between June 2024 and January 2026. The analysis focused on patients' demographic characteristics (gender, age), clinical symptoms, laboratory test indicators (complete blood count, inflammatory markers, biochemical parameters, coagulation function, electrolytes), imaging findings, and antibiotic treatment regimens, while also evaluating adjustments in antibiotic use before and after diagnosis and patient prognosis. Among the 13 patients, 7 were male (53.8%) and 6 were female (46.2%), with an age range of 54 to 84 years and a mean age of 64 ± 8.8 years. All patients presented with fever (body temperature 39–41°C), with 11 (84.6%) accompanied by cough and sputum production, 6 (46.2%) by dizziness, and 5 (38.5%) by headache. Laboratory findings showed that all 13 patients (100%) had elevated C-reactive protein (CRP), decreased albumin, and elevated fibrinogen; 10 patients (76.9%) had decreased eosinophil percentage; 9 patients (69.2%) had elevated aspartate aminotransferase (AST); and 9 patients (69.2%) had hyponatremia. Chest CT primarily revealed large patchy exudation and consolidation in the lungs, with bilateral lung involvement in 7 cases, unilateral involvement in 6 cases, pleural effusion in 2 cases, and air bronchogram sign in 5 cases. Before etiological confirmation, all patients received empirical antibiotic therapy, primarily with β-lactam/β-lactamase inhibitor combinations or carbapenems (including piperacillin-tazobactam in 7 cases, cefoperazone-sulbactam in 3 cases, and meropenem in 2 cases). After diagnosis, 10 patients (76.9%) had their regimen adjusted to doxycycline (alone or in combination). All patients improved and were discharged, with no fatalities. Chlamydia psittaci pneumonia is more common in middle-aged and elderly populations, with high fever being the primary clinical feature. Fever is the main clinical manifestation. Characteristics of laboratory tests include elevated C-reactive protein (CRP) with little or no increase in procalcitonin(PCT), decrease in percentages of lymphocytes and eosinophils, hypoalbuminemia and increase in fibrinogen, and pulmonary consolidation shown by chest CT. The use of multiple targeted amplification-high-throughput sequencing technology enables rapid diagnosis and accuracy. Doxycycline can effectively treat this disease, and prognosis is overall good. In clinical practice, in patients with community-acquired pneumonia of unknown etiology, this disease must be suspected and etiological testing performed early, to guide precise treatment.

Lei Wei, Shi Hongmei, Li Weiwei. Clinical Characteristics and Treatment Analysis of Chlamydia Psittaci Pneumonia Based on Multiple Targeted Amplification-High-Throughput Sequencing: A Single-Center Retrospective Study. Academic Journal of Medicine & Health Sciences (2026), Vol. 7, Issue 2: 56-65. https://doi.org/10.25236/AJMHS.2026.070208.

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