救命し得たemm1/ST28株による劇症型A群溶血性レンサ球菌感染症の1例

• Published in: 日本耳鼻咽喉科感染症・エアロゾル学会会誌 Vol. 7; no. 1; pp. 30 - 35
• Main Authors: 鈴木, 貴博, 東海林, 史, 野口, 直哉, 角田, 梨紗子, 粟田口, 敏一, 太田, 伸男
• Format: Journal Article
• Language: Japanese
• Published: 日本耳鼻咽喉科感染症・エアロゾル学会 20.01.2019; Japan Society for Infection and Aerosol in Otorhinolaryngology
• Subjects: emm1; ST28; streptococcal toxic shock syndrome; streptococcus pyogenes
• ISSN: 2188-0077; 2434-1932
• DOI: 10.24805/jjsiao.7.1_30

Streptococcal toxic shock syndrome (STSS) is a severe invasive infection characterized by the sudden onset of shock, multi-organ failure, and high mortality. Here we present a patient with STSS caused by Streptococcus pyogenes (emm1/ST28), who was rescued by rapid treatment. A previously healthy 64-year-old woman was referred to our hospital with cellulitis extending from the right neck to chest. CT scans revealed widespread subcutaneous inflammation, including the right cervical region, anterior thorax, and mediastinum. She soon developed septic shock and required tracheal intubation and vasopressor support in the intensive care unit. She failed to respond to intravenous antibiotics and vasopressor support, so emergency wide surgical debridement was performed. S. pyogenes with a highly mucoid morphology was detected in subcutaneous adipose tissue removed during the operation. Pathological examination revealed necrotizing soft-tissue infection. The patient was diagnosed with STSS and necrotizing soft-tissue infections, impaired renal function. Intravenous Meropenem (3 g/day) and Clindamycin (1800 mg/day) were initiated and she also received intravenous immunoglobulin. After S. pyogenes was isolated postoperatively, antibiotic therapy was changed to Ampicillin-sulbactam (9 g/day) and Clindamycin (1800 mg/day). She was transferred to the general ward on the 12th hospital day, and was discharged on the 53rd day. We characterized the isolate by emm typing and multilocus sequence typing (MLST). It was classified as the emm1/ST28 strain of S. pyogenes. emm1 is the predominant S. pyogenes genotype causing STSS in Japan and other countries, and it has a poor prognosis. ST28 also tends to cause severe infections. Although this patient had a poor prognostic infection according to genetic analysis, she was salvaged by rapid treatment.