Analysis of pertussis surveillance data (2022-2023) in a district of Beijing.

INTRODUCTION: This study describes the epidemiological and drug resistance characteristics of Bordetella pertussis (B. pertussis) isolated from chronic/protracted cough patients in Beijing, China. METHODS: A total of 160 patients with chronic/protracted cough from two hospitals in Beijing from 2022 to 2023 were enrolled in this study. Culture, real-time PCR assays and anti-pertussis toxin IgG antibody (PT-IgG) determination were used to confirm the pertussis diagnosis. Forty samples collected between September and November 2023 were screened for 200 respiratory pathogens via targeted next-generation sequencing (tNGS). Antimicrobial susceptibility testing for B. pertussis strains was performed via the E test. RESULTS: In this study, 98 patients were diagnosed with laboratory-confirmed cases of pertussis, for a diagnosis rate of 61.25% (98/160). The number of enrolled cases and laboratory-confirmed cases of pertussis increased from July to December 2023, and the highest number of enrolled and laboratory-confirmed cases of pertussis were observed in the age group of 6–12 years. In total, 49 B. pertussis isolates were derived from chronic/protracted cough patients, and the MICs of clindamycin (> 256 µg/mL), erythromycin (> 256 µg/mL), azithromycin (> 256 µg/mL) and sulfamethoxazole (> 1024 µg/mL) were greater than the maximum tested concentrations. B. pertussis-related gene fragments were detected in 17 samples via tNGS, with a detection rate of 42.50% (17/40). CONCLUSIONS: Patients with chronic/protracted cough in this region have a high rate of laboratory-confirmed pertussis. It is important to collect multiple samples during the course of pertussis, as well as to apply various pathogenetic and serologic methods to improve laboratory-based pertussis surveillance.