A Case of Chlamydophila psittaci Caused Pneumonia and Encephalitis Diagnosed by Metagenome Next-Generation Sequencing and Clinical Analysis

Introduction: Psittacosis represents a systemic infectious ailment primarily characterized by respiratory manifestations; however, the clinical presentation exhibits considerable diversity, posing challenges in promptly identifying this disease with its nonspecific features. Metagenomic next -generation sequencing (mNGS) serves as a valuable tool enabling expeditious pathogen identification and facilitating targeted therapeutic interventions. Case Presentation: An instance pertinent to this context involves a septuagenarian female patient who sought admission to Zhejiang Hospital on account of presenting with elevated body temperature, respiratory distress, and signs of altered mental state. Despite the initiation of empiric antibiotic therapy as the primary medical intervention, the patient's condition displayed a progressive deterioration. Notably, a subsequent investigation endeavor employing mNGS identified the presence of the Chlamydophila psittaci nucleic acid sequence, causative of psittacosis, within both her bloodstream and cerebrospinal fluid (CSF). The subsequent therapeutic administration of doxycycline not only elicited a marked amelioration in her clinical status but also facilitated her eventual discharge from our care. Conclusions: The coexistence of psittacosis lung infection and cerebral vasculitis is rare. Thorough documentation and analysis of such cases are essential for enhanced understanding and clinical consideration. In such cases where the infection is severe but does not respond to empirical antimicrobial therapy, mNGS can help with the diagnosis to identify the pathogen and target treatment.