Clinical features and outcomes associated with macrolide resistance - associated mutations in pediatric Mycoplasma pneumoniae pneumonia

OBJECTIVE: To investigate the clinical characteristics of macrolide resistance - associated mutations in hospitalized children with Mycoplasma pneumoniae pneumonia (MPP) and to evaluate their associations with severe Mycoplasma pneumoniae pneumonia (SMPP) and prolonged cough. METHODS: A total of 1,094 hospitalized children with MPP were retrospectively enrolled. Among them, 1,069 underwent A2063G/A2064G mutation testing, whereas 25 were not tested. Patients were classified into mutation-positive, mutation-negative, and untested groups according to mutation testing results. Clinical features, laboratory parameters, treatment profiles, and outcomes were compared among groups. Logistic regression and receiver operating characteristic (ROC) curve analyses were performed to identify risk factors for SMPP and prolonged cough. RESULTS: The proportion of SMPP was higher in the mutation-positive group than in the mutation-negative group. In addition, patients in the mutation-positive group exhibited a more pronounced inflammatory response and greater immune imbalance, as reflected by increased neutrophil percentage and D - dimer levels, along with decreased CD4 and CD8 counts. Univariate analysis showed that A2063G/A2064G mutation status was associated with both SMPP and prolonged cough. However, multivariable analysis identified fibrinogen and AST as independent factors associated with SMPP, while prolonged cough was additionally associated with the duration of azithromycin and clarithromycin therapy, as well as CD8 levels. CONCLUSION: Children with macrolide resistance-associated mutations exhibited a higher inflammatory burden and a higher unadjusted proportion of SMPP. However, after adjustment, A2063G/A2064G mutation status was not independently associated with SMPP or prolonged cough. Clinical management should integrate inflammatory markers, oxygenation status, and clinical presentation for individualized monitoring and treatment.