A rare case of lung abscess caused by Mycoplasma pneumoniae in an adult with chronic obstructive pulmonary disease

Lung abscess is a severe pulmonary infection usually caused by anaerobic or pyogenic bacteria. Mycoplasma pneumoniae (MP), a common cause of community-acquired pneumonia, is only rarely implicated in lung abscess formation. Available reports of MP-associated lung abscess have been largely confined to pediatric patients, and adult cases have not been clearly documented to date. We report a 74-year-old male with chronic obstructive pulmonary disease (COPD) who presented with chest pain, productive cough, and dyspnea. Chest CT revealed a cavitary lesion with an air-fluid level in the right lower lobe. Despite broad-spectrum antibiotics, the lesion progressed. Conventional cultures were negative, but targeted next-generation sequencing (tNGS) of bronchoalveolar lavage fluid identified 29,507 sequence reads of MP, confirming the diagnosis of MP-associated lung abscess. Antimicrobial therapy was switched to levofloxacin, leading to clinical improvement and marked radiological resolution. This case represents a rare presentation of lung abscess associated with Mycoplasma pneumoniae infection in an adult patient, with COPD likely serving as a predisposing factor. It highlights the importance of considering MP in cases of culture-negative lung abscess with atypical clinical features and underscores the value of targeted molecular diagnostics, such as tNGS, in guiding appropriate antimicrobial therapy and improving clinical outcomes.