Severe community-acquired pneumonia caused by Chlamydia pecorum.

Chlamydia pecorum is a zoonotic pathogen. Here, we report the first case of human infection with C. pecorum. A man aged 51 years with high fever and dry cough was diagnosed with severe community-acquired pneumonia and respiratory failure. C. pecorum was found responsible for the infection, which was detected from bronchoalveolar lavage fluid through metagenomic next-generation sequencing. C. pecorum infection was further identified by quantitative polymerase chain reaction and complement fixation test. The patient's condition improved rapidly after targeted treatment. He was a farmer with diabetes mellitus and had a history of close contact with sheep, which might result in C. pecorum infection. Our report could provide a direction for the diagnosis and treatment of human C. pecorum pneumonia.