LAUSR

Community-acquired pneumonia caused by Mycoplasma pneumoniae or Chlamydia pneumoniae is usually mild. Mycoplasma pneumoniae-related and C. pneumoniae-related acute respiratory distress syndromes (ARDSs) are rare. Moreover, to our knowledge, there are no published reports on ARDS caused by M. pneumoniae and C. pneumoniae coinfection. Here, we report a case of an immunocompetent young woman who was co-infected with M. pneumoniae and C. pneumoniae and was started on treatment with piperacillin and clarithromycin. Two days later, she developed ARDS. She recovered rapidly following a change of antibiotic treatment to levofloxacin and was discharged on day 12. We conducted exome sequencing followed by alternative filtering to search for candidate ARDS-related genes. We identified an intronic variant of unknown significance within leucine-rich repeat-containing 16A (LRRC16A), a gene previously identified as a significant locus for platelet count with a possible role in ARDS. This is a rare case of ARDS in a young adult caused by M. pneumoniae and C. pneumoniae coinfection. This case suggests that ARDS in young adults may be correlated with variants in LRRC16A. This requires confirmation by further case reports.