Abstract Rationale Mycoplasma infections have increased globally, including in Japan, and severe pneumonia due to Mycoplasma pneumoniae (M. pneumoniae) that was resistant to macrolide have been reported in the post-COVID-19 period, but its pathogenesis and detailed treatment regimens are still unclear. Case Series Four adult cases of M. pneumoniae pneumonia that required admission to the hospital in the 2024-2025 season are presented. Case 1: a 17-year-old male without a specific medical history who was admitted with pneumonia with severe dry cough and M. pneumoniae genes were detected by multiplex PCR from his sputum. The patient’s condition improved with minocycline and corticosteroids for five days. Case 2: a 88-year-old man with acute kidney injury who was admitted with severe respiratory failure and mycoplasma antigen was detected in his pharyngeal swab. He received lascufloxacin drip infusion with corticosteroids for 10 days, and improved soon. Case 3: 38-year-old woman with maxillary carcinoma and a history of aplastic anemia who was admitted with severe cough and mycoplasma antigen was detected in her pharyngeal swab. She received minocycline and corticosteroid drip infusion for a week and finally improved. Case 4: a 74-year-old man with multiple systemic atrophies who was admitted with severe cough and dyspnea. Mycoplasma antigen was detected from his pharyngeal swab and methicillin-susceptible Staphylococcus aureus (MSSA) were isolated from his sputum. The patient was diagnosed co-infection with mycoplasma and MSSA, and treated with sulbactam/ampicillin drip infusion and oral administration of minocycline for two weeks and improved. Conclusion All hospitalized adult patients with mycoplasma pneumonia were treated with antibiotics, such as minocycline and fluoroquinolone, along with corticosteroid co-administration, and all of them ultimately improved, although the chest X-ray findings varied. Antibiotics other than macrolides and corticosteroids may be an effective regimen for the treatment of severe mycoplasma pneumonia with potential macrolide resistance. This abstract is funded by: None
M Seki (Fri,) studied this question.