[Two cases of neonatal <i>Legionella</i> pneumonia].

Patient 1, a 12-day-old female infant, presented with fever, cough, dyspnea, and elevated infection markers, requiring respiratory support. Metagenomic next-generation sequencing (mNGS) of blood and bronchoalveolar lavage fluid revealed <i>Legionella pneumophila</i> (LP), leading to diagnoses of LP pneumonia and LP sepsis. The patient was treated with erythromycin for 15 days and azithromycin for 5 days, resulting in recovery and discharge. Patient 2, an 11-day-old female infant, presented with dyspnea, fever, elevated infection markers, and multiple organ dysfunction, requiring mechanical ventilation. mNGS of blood and cerebrospinal fluid indicated LP, leading to diagnoses of LP pneumonia, LP sepsis, and LP intracranial infection. The patient was treated with erythromycin for 19 days and was discharged after recovery. Neonatal LP pneumonia lacks specific clinical symptoms, and azithromycin is the preferred antimicrobial agent. The use of mNGS can provide early and definitive diagnosis for severe neonatal pneumonia of unknown origin.