Clinical diagnosis and etiology of C. psittaci pneumonia patients based on metagenomic next-generation sequencing
In this paper, we firstly perform the etiological analyses by mNGS to assist physicians with a comprehensive understanding and to highlight the severity of C. psittaci pneumonia. This is the first documented that etiology and coinfection analysis in C. psittaci pneumonia patients in China, with cases about human-to-human transmission of C psittaci are on a rise.  Importantly, coinfection with C. psittaci and other respiratory pathogens in patients are at an increasing risk, and the process of concomitant infection is still unclear. Our study systematically analyzed the clinical manifestation and pathogen coinfections. This is significant because C.psittaci infection in humans can cause serious disease, including pneumonia, acute respiratory distress syndrome (ARDS), sepsis, septic shock, and multiple organ system failures, and death. Diagnosis of C.psittaci infection can be very difficult, tests for C psittaci are often not included in routine microbiological diagnostics, so most human C psittaci infections globally remain undetected. Therefore, the incidence and disease burden might be greatly underestimated. If the clinical characteristics of C.psittaci pneumonia could be identified and the tests could be performed in all directions at early stage, there would not be time delay for the applying of targeted therapy.