Outbreak of Streptococcus pyogenes emm89 ST646 in a head and neck surgical oncology ward

Brian Hayama, Sohei Harada, Masahiro Suzuki, Yohei Doi, Yusuke Nomura, Kotaro Aoki, Kazumi Takehana, Tomomi Akatsuchi, Taisuke Enokida, Koichi Takeda, Akira Seto, Hiroki Mitani, Daisuke Ohkushi

Research output: Contribution to journalArticlepeer-review


Streptococcus pyogenes causes a variety of human infections, and hospital outbreaks with this pathogen have also been reported. The purpose of this study is to describe the clinical characteristics of an outbreak of S. pyogenes involving 15 patients and four healthcare workers (HCWs), as well as the molecular characteristics of the causative isolates. The course and response to the outbreak were reviewed, and information on the characteristics of the patients was extracted retrospectively from the medical records. Whole-genome sequencing of the 16 causative isolates (14 from patients and two from HCWs) was also performed. All 15 patients were postoperative of head and neck cancer with tracheotomy, and 12 had invasive infections, primarily surgical site infections, all of which resolved without causing serious illness. All but the first case was detected more than 7 days after admission. S. pyogenes was detected in two patients after empiric antimicrobial administration was performed on all inpatients and HCWs, and the outbreak was finally contained in approximately 2 months. All isolates detected in patients and HCWs belonged to emm89/clade 3, a hypervirulent clone that has emerged worldwide and was classified as sequence type 646. These isolates had single nucleotide polymorphism (SNP) differences of zero to one, indicating clonal transmission. This study demonstrated an outbreak of S. pyogenes emm89/clade 3 in a ward of patients with head and neck cancer. The global emergence of hypervirulent isolates may increase the risk of outbreaks among high-risk patients.

Original languageEnglish
JournalMicrobiology spectrum
Issue number5
Publication statusPublished - 05-2024

All Science Journal Classification (ASJC) codes

  • Physiology
  • Ecology
  • General Immunology and Microbiology
  • Genetics
  • Microbiology (medical)
  • Cell Biology
  • Infectious Diseases


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