# Toxic Shock Syndrome Caused by Streptococcus dysgalactiae Subspecies equisimilis: A Report of a Rare Pediatric Case

## TL;DR

A rare case of toxic shock syndrome in a child caused by a specific strain of Streptococcus dysgalactiae subsp. equisimilis is reported, highlighting unusual clinical features and genetic mutations.

## Contribution

The paper presents a novel pediatric case of SDSE-induced STSS with identification of the stC1400 emm subtype and associated genetic mutations.

## Key findings

- A five-year-old child with Down syndrome developed STSS caused by SDSE, a rare occurrence in children.
- The SDSE strain isolated was identified as emm subtype stC1400 with mutations in csrS and srrG genes.
- The patient responded well to treatment and was discharged after three weeks.

## Abstract

Streptococcal toxic shock syndrome (STSS) is a severe invasive infection that has a high mortality rate. It is mainly caused by Streptococcus pyogenes. Nevertheless, STSS is also known to be caused by a group G Streptococcus identified as Streptococcus dysgalactiae subsp. equisimilis (SDSE). Invasive SDSE infection predominantly occurs in elderly individuals but is extremely rare in children. Furthermore, reports on STSS caused by SDSE are limited; hence, the clinical aspects and type of invasive mature M protein (emm) gene involved are unknown. A five-year-old girl with Down syndrome, tracheomalacia, and laryngomalacia presented to the emergency department with generalized edema of her face and upper body. She had undergone a tracheostomy and was receiving home ventilation. On admission, she showed hypotension (64/22 mmHg) with impaired consciousness. Blood testing showed elevated levels of inflammatory markers. Blood culture revealed the presence of SDSE and she was consequently diagnosed with STSS. The patient responded well to treatment and was discharged three weeks after admission. The emm subtype of the isolated SDSE strain was stC1400, with mutations in csrS and streptolysin S regulatory RNA in group G Streptococcus (srrG) genes. In this article, we report a case of STSS in a child caused by the stC1400strainof SDSE.