Clinical efficacy of trimethoprim-sulfamethoxazole treatment for pediatric pertussis in macrolide-resistant endemic regions: A retrospective cohort study

OBJECTIVE: To assess the efficacy and influencing factors of sulfamethoxazole-trimethoprim (SXT) in children with pertussis in regions with a high prevalence of macrolide-resistant Bordetella pertussis (MRBP). METHODS: A total of 317 PCR-confirmed pediatric pertussis cases treated with SXT were retrospectively analyzed. Patients were categorized into short-term (5-7 days, n = 93) and long-term (10-14 days, n = 65) treatment groups. Clinical outcomes, adverse events, and potential predictors of treatment response were analyzed. RESULTS: The median interval from symptom onset to SXT initiation was 12 days (IQR: 9-15). Following SXT therapy, 243 patients (76.7%) achieved clinical remission, 68 (21.4%) showed partial improvement, and 6 (1.9%) experienced no relief, without clinical deterioration. Multivariate analysis identified nucleic acid negative conversion as a independent predictor of clinical remission (OR, 5.14, 95% CI: 2.66-9.88, p < 0.001). Compared to the short-course group, the long-course group demonstrated significantly higher rates of both clinical remission (83.1% vs. 66.7%, p = 0.022) and nucleic acid clearance (87.7% vs. 71.0%, p = 0.013). No serious adverse events were reported. Skin lesions were the most frequent adverse events (5.1%), with no significant difference between groups (3.2% vs. 7.7%, p = 0.373). CONCLUSIONS: SXT effectively alleviates clinical symptoms of pertussis in children in high MRBP prevalence regions. Nucleic acid negative conversion predicts clinical remission. An extended SXT course (10-14 days) demonstrates superior efficacy to a shorter course (5-7 days). No serious adverse events were observed; skin lesions were the most common side effect.