高齢者および慢性疾患患者の入院施設におけるMRSA感染経路対策の検討—種々の型判別法によるMRSA分離株の分類と伝播経路の解析結果から

Transmission of Methicillin-resistant Staphylococcus aureus in a Hospital for Aged and Chronically III Inpatients

はじめに

　私たちは，看護ケアの現場において寝具の清潔を保つことが，院内感染を防止する上で重要だと考え調査研究を続けてきた。1993（平成5）年2月19日から4月10日にかけて“生活自由度による寝具類の細菌汚染の実態”について行なった調査研究によって，対象別，寝具別の交換基準を明らかにすることができた^15）。

　しかし，この調査対象であった，急性期病棟および慢性期病棟に入院中の患者60名のうち11名の寝具（マットレス以外）からメチシリン耐性黄色ブドウ球菌（以下，MRSA）が検出された。11名中2名はMRSAの感染が明らかなため，個室隔離中の患者であった。その他の9名の病室は，両病棟に散在していた。

　When we tested bacterial contamination in the linens of aged or chronically ill inpatients in a general hospital (114 beds), 11 out of 60 patients were found to have methicillin-resistant Staphylococcus aureus (MRSA).

　Two of these were MRSA infections. Furthermore, 6 patients mostly olderly and with chronic diseases, were newly infected with MRSA after this surveillance period. So as to clarify the transmission route of MRSA in the hospital, we classified 12 MRSA strains into 4 types by several criteria such as types of coagulase, enterotoxin, toxicshock syndrome toxin, sensitivity to antibiotics, plasmid contents, and restriction endonuclease digestion patterns of chromosomal DNAs. At the same time, we followed up the movement of patients in wards and conditions of patient contact with medical staff in the hospital. The data obtained revealed a specific correlation between one of the MRSA strains and a doctor, suggesting a contribution from medical staff to the transmission of MRSA in the hospital. It is necessary, therefore, to practice more careful protection procedures against bacterial infection especially in hospitals for aged and chronically ill patients who are vulnerable to various infectious agents.