Macrolide-resistant Bordetella pertussis strains in Taiwan, 2010–2024

DOI: 10.6524/EB.202511_41(21).0001

Shu-Man Yao, Ying-Yan Chen, Sheng-Ping Chou, Tzu-Chieh Wei, Yu-Chun Wang, Chuen-Sheue Chiang*

2025 Vol.41 NO.21

Correspondence Author： Chuen-Sheue Chiang

Abstract：

In 2020, through the collaborative study on Bordetella pertussis between the Taiwan Centers for Disease Control and the National Institute for Infectious Diseases　in Japan, the first two macrolide-resistant Bordetella pertussis (MRBP) strains were identified in Taiwan in 2011 and 2012. Therefore, we began to monitor the antimicrobial susceptibility of all newly obtained B. pertussis strains in Taiwan. Here, we report the analysis of 71 B. pertussis strains collected during 2010–2024 for resistance against trimethoprim-sulfamethoxazole and macrolides, including azithromycin, clarithromycin, and erythromycin. All strains were sensitive to trimethoprim-sulfamethoxazole. Ten strains were macrolide-resistant, with minimum inhibitory concentration (MIC) > 256g/mL against all three macrolides. The first MRBP strain was isolated in 2011, followed by one strain in 2012, one in 2015, two in 2020, one in 2022, and four in 2024. All 10 MRBP strains had an A2047G mutation in the 23S rRNA gene, causing the macrolide-resistant phenotype. Further characterization of these 10 MRBP strains indicated that these strains may have originated from China. The MRBP strains from 2011 to 2022 had the ptxA1/prn1/fim3-1/ptxP1 genotype, while MRBP stains from 2024 had the ptxA1/prn2/fim3-1/ptxP3 genotype. The multilocus variable-number tandem repeat analysis (MLVA) types were MT195, MT28, MT104 and MT290. The pulsed-field gel electrophoresis (PFGE) DNA fingerprinting separated the 10 MRBP strains into 3 groups. Three strains isolated in 2024 had identical fingerprints, which included one strain imported from China. Also, whole genome sequencing for the first 2 MRBP strains indicated that they were closer to MRBP strains from China. Our results provide guidance for the treatment and antibiotic prophylaxis of pertussis, and indicate that continued monitoring of antimicrobial susceptibility of B. pertussis strains is essential.