A VV-ECMO supported severe pneumonia caused by Chlamydia abortus: a case report

Abstract Background: Human infection with Chlamydia abortus is very rare, mainly described as septicemia and abortion in pregnant women with previous Chlamydia abortus exposure. Though there is a case of atypical pneumonia caused by Chlamydia abortus in 2016, none of the reported infections manifested primarily as severe hypoxemia. Case Presentation: A 69-year-old male farmer admitted to our ICU for pneumonia caused severe hypoxemia, with PaO2 /FiO2 ratio dropped to 53.1 mmHg when under mechanical ventilation. Bronchoalveolar lavage fluid(BALF) for untargeted metagenomic NGS was taken soon after VV- ECMO support. Sequencing results indicate Chlamydia abortus is the pathogen. The patient operated a farm raising more than a hundred pigs and some poultry before the disease, with no ruminant in the farm, and the possibility of contact was denied. Two weeks later, the patient was weaned from ECMO, recovered, and was discharged a month later. Conclusion: Chlamydia abortus infection in humans may as well cause severe pneumonia with hypoxemia and need ECMO support. clinician veterinarians and public health officials should be aware of possible severe pulmonary infection due to Chlamydia abortus.