著者

翠川 裕 仲井 正昭 翠川 薫 新家 光雄

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.80, no.3, pp.165-170, 2016 (Released:2016-02-25)

参考文献数

10

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A novel method for detecting antimicrobial activity using an innate property of the Salmonella bacteria, namely, the ability of Salmonella to produce hydrogen sulfide (H2S) was developed in this study. The effectiveness of the method was evaluated by comparing the antibacterial activity of copper to that of aluminum. Salmonella was inoculated over the entire surface of deoxycholate hydrogen sulfide lactose (DHL) agar plates that included Ammonium ferric citrate (C6H8FeN). Approximately 25 μL of cupric chloride (CuCl2, 1% weight ratio) solution or aluminum chloride (AlCl3, 1% weight ratio) solution was added to the center of the medium. The surface of the medium was covered with plastic PET (polyethylene terephthalate) material to induce an anaerobic state. Salmonella was cultured under anaerobic conditions at 310 K (37℃) for 86.4 ks (24 h). The antibacterial activity of copper was determined by observing the medium surface color change due to iron sulfide (FeS) formation, which was caused by the production of H2S by Salmonella; blackness indicated presence of newly formed FeS. A quantitative evaluation of copper's antimicrobial activity was performed using a gradient of CuCl2 concentrations; results were compared with those of the present standard method, Kirby-Bauer disk diffusion method on the Mueller Hinton medium. Finally, in order to evaluate the antibacterial activity of metals, Salmonella was inoculated on DHL agar plates. Subsequently, Japanese coins (1 yen, 5 yen, 10 yen, 50 yen, 100 yen and 500 yen coins) were placed on the agar and cultured at 310 K for 86 ks. Salmonella cultured in the presence of AlCl3 produces black color, while no blackening is observed with CuCl2, suggesting that copper possesses an antibacterial property against Salmonella. CuCl2 suppresses H2S production by Salmonella, as Cu2+ forms a transparent circle or ellipse (new halo) around the point at which CuCl2 had has been plated. The size of the new halo increases in direct proportion to the concentration of CuCl2. The halo is no longer visible at 0.034 mg of CuCl2 in our method, while the halo disappears with 4.34 mg of CuCl2 in the Kirby-Bauer method. Therefore, the present method is 129 times more sensitive than the standard method, suggesting increased usefulness and effectiveness in testing antibacterial activity. No FeS-dependent black circle is formed under any of the coins, with the exception of the 1-yen coin, which contains aluminum and no copper. Therefore, the copper-containing coins have an antibacterial effect.

著者

中村 哲 翠川 裕 波部 重久 松田 肇 翠川 薫 渡部 徹 中津 雅美 二瓶 直子 鈴木 琴子 黒倉 壽 風間 聡 三好 美紀 桐木 雅史

出版者

独立行政法人国立国際医療研究センター

雑誌

基盤研究(A)

巻号頁・発行日

2010

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ラオス国との共研究の主対象となったラオスの消化管寄生虫感染症に関して、現地調査により山岳部と平地とで寄生虫相が異なることを示唆した。特に淡水魚類の生食を介して感染するタイ肝吸虫類の感染が都市周辺域において顕著に高いことを示した。さらに、山岳地居住民の感染率と健康調査データの解析からリスク因子として、年齢や識字率、集落での衛生的な飲み水の利用割合、民族の比率を見出した。そして、これらの因子による重回帰で得られるリスクマップを含めた、地区内または広域でのリスク管理手法を示した。