柿沼 藍¹, 荒川 まい¹, 鯉渕 晴美², 中里 恵梨香¹, 木村 由美子¹, 大澤 正明¹, 山本 さやか², 紺野 啓², 山田 俊幸², 谷口 信行²

Ai KAKINUMA¹, Mai ARAKAWA¹, Harumi KOIBUCHI², Erika NAKAZATO¹, Yumiko KIMURA¹, Masaaki OOSAWA¹, Sayaka YAMAMOTO², Kei KONNO², Toshiyuki YAMADA², Nobuyuki TANIGUCHI²

¹自治医科大学附属病院臨床検査部, ²自治医科大学附属病院臨床検査医学講座

¹Department of Clinical Laboratory, Jichi Medical University, ²Department of Clinical Laboratory Medicine, Jichi Medical University

キーワード : ultrasound gel, nosocomial infection, infection control, hand hygiene

目的：超音波検査室は適切な感染対策が必要とされる場であるにもかかわらず，ゲルボトルやウォーマーの運用については明確な定めがなく，現状では感染対策上不十分と考えられる．諸外国では過去に超音波ゲルを介した院内感染事例が報告されており，わが国での発生も懸念される．そのため，我々は現状のゲルや周囲環境の汚染状況の調査，洗浄後の経過観察を行い，院内感染対策を目的としたゲルボトルやウォーマーの取扱い方法の確立を目指した．対象と方法：洗浄前，洗浄後，ゲル使い切り後，洗浄3週間後のゲルボトルやウォーマー，ボトルの乾燥かごより検体を採取し，培養・同定検査および菌量の測定を行った．結果と考察：洗浄前にはボトル口や複数のウォーマーから皮膚常在菌や枯草菌が検出され，検査手技の影響や環境からの汚染が考えられた．十分な洗浄・乾燥後では，いずれの部位からも菌は検出されなかった．ゲル使いきり後および洗浄から3週間後では，ウォーマーから枯草菌が検出された．結語：検査環境の常在菌や環境菌による汚染は，十分な洗浄・消毒により除去されることが明らかとなった．また適切な洗浄により，ボトルの再利用は可能であると考えられた．

Purpose: The present study investigated the contamination of ultrasound accessories. The goal of this study was to establish a protocol for disinfecting gel bottles and gel warmers. Subjects and Methods: Bacterial samples were collected from gel bottles, gel warmers, gel containers, and the basket used for drying washed objects, before and after washing the objects, except for the basket, for which the sample was collected only at the beginning of the study. Additionally, samples from gel bottles and gel warmers were collected when the gel in each gel bottle was depleted, as well as 3 weeks after washing. The samples were inoculated onto Tryptic soy agar plates, and the plates were incubated at 35°C and 5% CO₂ for 48 hr. The species of the bacterial colonies on the plates were identified automatically, and the number of bacteria was analyzed semiquantitatively. Results and Discussion: Staphylococcus caprae were detected in the samples collected from one gel bottle and one gel warmer, and Bacillus subtilis from one gel warmer before cleaning, while after cleaning no bacteria were detected. B. subtilis was detected from specimens collected from two gel warmers when the gel in gel bottles was exhausted and 3 weeks after cleaning. Only commensal or environmental bacteria, but no pathogenic bacteria, were detected from the samples in the present study. This finding suggested that ultrasound accessories such as gel bottles or gel warmers were contaminated by clinical procedures during ultrasound examinations. Gel bottles should not be refilled from larger gel containers. As no bacteria were detected after cleaning, gel bottles can be reused after sufficient cleaning and drying. Conclusion: In this report, we presented a cleaning method for reuse of accessories such as gel bottles and gel warmers contaminated with commensal or environmental bacteria. Our results confirmed that this method sufficiently removed the bacterial contamination on the accessories.