都内A老人病院入院患者の口腔・鼻腔内MRSAの分離—移動能力とMRSAの定着との関連に注目して

Isolation of MRSA from oropharynx and nasopharynx of inpatients in a hospital for the elderly in Tokyo Metropolis : focusing on the relation between their activities of moving and colonization of MRSA

　都内A老人病院の介護力強化病棟に入院中の患者84名を対象として，口腔内および鼻腔内から得られた検体からMRSA（methicillin-resistant Staphylococcus aureus）の分離を行った．その結果，口腔内もしくは鼻腔内におけるMRSA保有率は20.2％（84名中17名）であった．また，口腔内から15.5％，鼻腔内から14.3％にMRSAが検出され，両部位からの分離率はほぼ同じであった．口腔内および鼻腔内ともにMRSAを保有していた患者8名全員が移動に全介助を要し，口腔内のみに保有していた患者5名のうち4名が自立歩行していた.MRSA保有者を2週間後に再検査したところ，MRSAが消失した患者4名は全員が自立歩行しており，移動能力が良好な高齢者は，一時的な菌の保有にとどまり，保菌者とはなりえないことが示唆された．さらに，21種類の薬剤感受性パターンによりMRSAの感染経路の解明を試みたが，口腔内から分離されたMRSAのパターンは他の患者とは一致せず，口腔内のMRSAの伝播は少ないことが考えられた．

　In a hospital for the elderly in Tokyo Metropolis, samples of oropharynx nasopharynx and were collected from 84 inpatients in wards for care. The presence of MRSA (methicillin-resistant Staphylococcus aureus) was investigated, and detection rate was 20.2% (17 out of 84 inpatients) in total. In details, MRSA was isolated from 15.5% of oropharynx and 14.3% of nasopharynx, and detection rate of the two sites was much the same. All inpatients (8 persons) who carried MRSA in oropharynx and nasopharynx could not walk without help. On the other hand, 4 out of 5 inpatients who carried MRSA only in oropharynx could walk under their own power. Moreover, a follow-up study at an interval of 2 weeks was perfomed, and all inpatients (4 persons) who became negative of MRSA could walk under their own power. This may indicate that a inpatient in good activities of moving may have MRSA transiently but not become a carrier. For the elucidation of route of MRSA transmission, susceptibility testing was perfomed using 21 different antibiotics. Typing of a MRSA strain detected in oropharynx was not coincided with that of other inpatients, suggesting that the nosocomial infection from oropharynx seldom occurred.