Macrolide-Resistant Mycoplasma pneumoniae Infection Successfully Treated With Doxycycline and Immunomodulators in a Pediatric Patient: A Case Report

Mycoplasma pneumoniae (MP) is a common cause of community-acquired pneumonia in children and usually responds well to macrolide antibiotics. However, in recent years, the emergence of macrolide-resistant Mycoplasma pneumoniae (MRMP) is becoming a significant concern in some areas of the world, particularly in Asia, though it remains rare and not commonly reported in the United States. We report a case of a previously healthy early teenage boy presenting with persistent dry cough, chest tightness, sore throat, headache, fatigue, and fever. Despite completing a full course of azithromycin, his symptoms persisted, and radiographic findings showed no improvement. Repeat multiplex polymerase chain reaction(PCR) confirmed ongoing MP infection, and resistance genes were identified. The patient was subsequently treated with doxycycline, along with systemic corticosteroids and bronchodilators, which led to rapid clinical and radiologic improvement within 72 hours of doxycycline initiation. This case highlights the importance of considering MRMP in patients with confirmed MP infection who fail to respond to macrolide therapy, even in areas with low prevalence of mycoplasma infection. Despite the presence of atypical resistance genes in our case, the patient's clinical course strongly supported the diagnosis of MRMP. It also underscores the potential role of adjunctive immunomodulator therapies, such as corticosteroids, alongside antibiotics in managing airway inflammation and bronchospasm associated with MP infection. Early diagnosis, appropriate antibiotics, and the use of immunomodulators are critical for achieving a fast recovery from the illness.