Poster Presentation Lancefield International Symposium for Streptococci and Streptococcal Diseases 2025

Expansion scarlet fever-associated mobile genetic elements among group A Streptococcus in Taiwan (#13)

Chuan Chiang-Ni 1 2 , Chien-Chung Lee 2 3 , Chia-Yu Chi 4 5 , Mu-Chin Lin 6 , Meng-Hsuan Pan 6 , Chih-Yun Hsu 1 , Cheng-Hsun Chiu 2
  1. Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
  2. Molecular Infectious Disease Research Center, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan
  3. Division of Neonatology, Department of Pediatrics, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan
  4. National Institute of Infectious Disease and Vaccinology, National Health Research Institutes, Zhunan, Miaoli, Taiwan
  5. Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
  6. Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University , Taoyuan, Taiwan

In the past few decades, the global resurgence of scarlet fever and invasive group A Streptococcus (GAS) infections have been reported. In East Asia, specifically in Hong Kong and China, the emm12- and emm1-type GAS carried the homologs of ΦHKU.vir and ICE-emm12 were over-presented in scarlet fever cases. Nonetheless, the toxigenic M1UK lineage clone related to the increase of invasive GAS infection in Europe was only reported in Taiwan and Japan until Dec 2024. Taiwan is geographically close to Hong Kong and China. This study aims to investigate the epidemiology of scarlet fever-associated mobile genetic elements in M1UK and various emm-type GAS isolates in Taiwan. The core genome-based single nucleotide polymorphism analysis showed that the emm12 isolates identified in Taiwan were phylogenetic highly related to the emm12 isolates identified in Hong Kong. Furthermore, the nucleotide sequence of scarlet fever-associated elements in Taiwan emm12 isolates shared highly sequence identity with ΦHKU.vir and ICE-emm12 found in Hong Kong. The homologs of these scarlet fever-associated elements were identified in emm1, emm11, emm89, and emm90 isolates. Our results showed that the emm12 isolates carried the scarlet fever-associated elements identified in Taiwan and Hong Kong would share the same origin. In Taiwan, the scarlet fever-associated genetic elements would be transferred from emm12 isolates to multiple emm-type isolates, including the toxigenic M1UK clone. Monitoring the expansion of these mobile genetic elements among GAS would provide insights into shifts in emm types over time.