Jia Zhang,1 Zhijian Wang,1 Yushan Jiang,1 Dan Zhang,2 Wanyan Den,3 Danni Wang,1 Jiayi Peng,1 Jiajun Li,4,* Wenxiang Huang1,* 

1Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People’s Republic of China; 2Department of Emergency and Critical Care, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People’s Republic of China; 3Department of Pathogenic Biology, College of Basic Medicine, Chongqing Medical University, Chongqing, 400016, People’s Republic of China; 4Department of Infectious Diseases, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Wenxiang Huang, Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People’s Republic of China, Email wenxiang_huang@163.com

Abstract: Streptococcus pyogenes, also known as Group A Streptococcus (GAS), can cause severe invasive diseases with high fatality rates. We report a case of necrotizing fasciitis and myositis complicated by Streptococcal Toxic Shock-Like Syndrome (STSS) caused by the invasive emm 22/ST46 strain of Streptococcus pyogenes in China. A previously healthy 57-year-old Chinese Canadian man presented with right calf pain and ulceration following a hike in the Gobi Desert, which progressed to unconsciousness and severe infection. Despite initial treatment, his condition deteriorated, leading to his transfer to our intensive care unit. Metagenomic Next-Generation Sequencing identified Streptococcus pyogenes, and antimicrobial susceptibility testing revealed resistance to erythromycin, tetracycline, and clindamycin. Despite broad-spectrum antimicrobial therapy, debridement, and supportive measures, the patient’s condition necessitated amputation of the right lower limb. He recovered and was discharged from the hospital on Day 43. Whole-genome sequencing of the isolate identified 15 multiple virulence factors. Phylogenetic analysis revealed that the closest relative of the isolate was a strain identified in China. This case underscores the importance of early recognition and treatment of invasive GAS infections to prevent severe outcomes, and we should pay attention to invasive emm 22/ST46 GAS infections in China.

Keywords: group A Streptococcus, streptococcal toxic shock-like syndrome, amputation, superantigens, metagenomic next-generation sequencing