速乾性擦式消毒剤による手指消毒後のセレウス菌などのグラム陽性有芽胞桿菌の残存  [in Japanese] Survival of Gram-Positive Spore-Forming Bacteria Including Bacillus cereus after Hand Washing Using Alcohol-Based Handrub  [in Japanese]

手洗いおよび手指消毒は最も基本的な感染防止策である.現在,速乾性擦式消毒剤による手指衛生が国際的なゴールドスタンダードとなっている.しかし,我々の調査では,2004年に10.4%(48人中5人),2005年に34.3%(35人中12人)と多くの無効例が認められた.2005年の検体について,コロニーの形態より円形,不整形,拡散性コロニーに大別し,残存菌の性状を調べた.円形コロニーはブドウ球菌属の菌であり,不整形・拡散性のコロニーはグラム陽性有芽胞桿菌であると考えられた.消毒後の菌数が消毒前と同数以上あるいは300個以上の無効例の中で,ブドウ球菌属の菌が残存したと考えられる場合が3例,セレウス菌を含むグラム陽性有芽胞桿菌が残存したと考えられる場合が9例であった.医療現場では,速乾性擦式消毒剤による手指消毒を過信することなく,必要に応じて滅菌手袋の着用などの対策を講じるべきである.

Hand washing is the most fundamental method for preventing infection. Currently, hand washing with an alcohol-based handrub is the international gold standard method. However, in our study we found many samples of ineffective hand washing using an alcohol-based handrub. The rates of ineffective samples were 10.4% (5/48) in 2004 and 34.3% (12/35) in 2005. We examined the morphology by Gram staining and biochemical properties of the bacteria which remained after hand washing in 2005. Their colonies were divided into 3 groups (round colonies, irregular-shaped and diffusive colonies). The round colonies were considered Staphylococcus spp., and the irregular-shaped colonies or diffusive colonies were considered Gram-positive spore-forming bacteria. In the 12 ineffective hand washing samples (more than the same number of bacteria colonies as before hand washing, or ≧300), there were 3 samples considered to be the result of the survival of Staphylococcus spp., and 9 samples considered to be the result of the survival of Gram-positive spore-forming bacteria including Bacillus cereus. Based on these results, we should take careful measures, such as wearing sterile gloves if necessary. We should never be overconfident regarding the effect of hand washing.