市中感染型MRSA

Detection and clinical significance of multidrug-resistant organisms：community acquired methicillin-resistant Staphylococcus aureus

　MRSA(methicillin-resistant Staphylococcus aureus)は院内感染症の主要菌であったが，近年，市中感染症からも検出されるようになってきている．市中感染型MRSA(community acquired MRSA；CA-MRSA)は大部分が皮膚・軟部組織感染症を引き起こすが，時に壊死性肺炎や敗血症，壊死性筋膜炎といった致命的な疾患を引き起こす．米国では，USA300と命名されたクローンが急激に増加傾向にあり，現在，CA-MRSAは最も注意すべき病原体の一つとして考えられている．疫学そのほかの解析にはSCCmecタイピング，パルスフィールドゲル電気泳動(PFGE)，MLST(multi locus sequence typing)などが用いられているが，日本におけるCA-MRSAの現状については不明な点も多い．今後，国内においてもCA-MRSAがさらに拡大し，深刻な状況に陥る可能性もあるため，慎重な対応を取っていく必要がある．

MRSA(methicillin-resistant Staphylococcus aureus)has been a major causative agent of nosocomial infection. However, recently MRSA has become increasingly isolated from community associated infections. Although most community acquired MRSA(CA-MRSA)disease has been infection of skin or soft tissue, CA-MRSA also cause highly invasive, rapidly progressive, life-threatening diseases such as necrotizing pneumonia, severe sepsis and necrotizing fasciitis. In the USA, CA-MRSA known as USA300 is increasing rapidly and is now the leading cause of community associated bacterial infection. Analysis using SCCmec typing, pulsed field gel electrophoresis(PFGE), multi locus sequence typing(MLST), spa typing, and toxin gene pattern analysis have been used for epidemiological studies. But, we have little information about CA-MRSA in Japan. CA-MRSA may spread more in our country, so we should take care to respond to this danger.