ストレプトリシンSと,グループGの estreptococcusによって引き起こされる死滅性感染症
Deepali Humar1, Vivekananda Datta, Darrin J Bast
1Department of Medicine, Division of Infectious Diseases, University of California, San Diego 92093, USA. vnizet@ucsd.edu
Lancet (London, England)
|January 26, 2002
まとめ
ベータ血解性群G型ストレプトコッカスは,A型ストレプトコッカスのような重度の死滅性軟組織感染症を引き起こす. これは,共有遺伝子のオペロンによって暗号化されたストレプトリシンS (SLS) エクソトキシンが,疾患の病原化に寄与しているためです.
科学分野:
- 微生物学 微生物学とは
- 感染症 感染症は感染症です.
- パトジェネシス (病原生)
背景:
- 3人の患者で重度の死滅性軟組織感染症 (NSTI) が観察されました.
- 感染の原因は,ベータ・ヘモリティックグループG型ストレプトコッカスでした.
- 臨床プレゼンテーションは,侵入的なA群のストレプトコッカス感染症を模倣した.
研究 の 目的:
- グループG Streptococcusにおけるβ-血解性活性の遺伝的基礎を決定する.
- Gグループ Streptococcus beta-haemolysinが死滅性感染症を引き起こす役割を調査する.
- グループGとグループAの病原性メカニズムを比較するために.
主な方法:
- ハイブリジゼーション,DNAシーケンシング,標的型変異遺伝子を用いて,β-ヘモリシスに起因する遺伝子を特定した.
- 補足研究により,観察されたフェノタイプの遺伝的根拠が確認されました.
- ネズミのモデルを使用して,感染の発症におけるβ-ヘモリシンの必要性を評価しました.
主要な成果:
- グループGのストレプトコッカスは,グループAのストレプトコッカス・サグ・オペロン (Streptococcus sag operon) の同類体を持ち,ストレプトリシンS (SLS) をコードする.
- sagA遺伝子の変異は,グループG Streptococcusにおけるβ-血解活性を廃止した.
- 野生型菌株に感染したマウスは死滅症を発症したが,SLS陰性変異体に感染したマウスは死滅症を発症しなかった.
結論:
- ベータ-血液分解性グループGのストレプトコッカスは,重度の死滅性軟組織感染症を引き起こし,臨床的にA群のストレプトコッカスによって引き起こされる感染症と区別できない.
- 機能的なサグオペロンホモローグによってコード化されたエクソトキシン・ストリープトリシンS (SLS) は,グループGのストリープトコッカスのベータ-血液溶解性現象型に起因する.
- SLS発現は,ストレプトコック性死滅性軟組織感染症の病原性における重要な要因である.
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