Urayama S, Kozarek R A, Sumida S, Raltz S, Merriam L, Pethigal P
Department of Internal Medicine, Virginia Mason Medical Center, Seattle, Washington 98111, USA.
Gastrointest Endosc. 1996 May;43(5):451-6. doi: 10.1016/s0016-5107(96)70284-5.
High-level disinfection of endoscopes has traditionally been undertaken by manual or automatic scope cleaning plus a 10 to 20 minute soak in 2% alkaline glutaraldehyde. Mycobacteria species are less sensitive to glutaraldehyde, and a 45-minute instrument soak has recently been recommended by the manufacturer. Because of concerns over endoscope damage, need for more endoscopes, and perception that the current cleaning method is adequate, we prospectively studied mycobacteria-contaminated endoscopes at various stages of the cleaning process.
All work was done under a laminar flow hood in a microbiology laboratory. Five gastrointestinal scopes were contaminated with 10(8) colony forming units per milliliter (CFU/mL) of Mycobacterium chelonei, an atypical mycobacterium similar in chemical resistance to Mycobacterium tuberculosis but with less infectious potential. Cultures of the sheath, biopsy channel, and elevator channel were taken at baseline, after manual cleaning, and after 10, 20, and 45 minutes to glutaraldehyde soak both before and after alcohol rinse.
Manual cleaning resulted in a mean of 4.7 log10 reduction in viable mycobacterial colonies. Qualitative studies of the external endoscope surface as well as the air-water valve showed no detectable organisms after a 10-minute exposure to alkaline glutaraldehyde. Conventional quantitative culture techniques of the channels demonstrated one endoscope out of five with consistent growth after a 10-minute exposure to glutaraldehyde. Following alcohol treatment, there was no significant colony growth. In contrast, a quantitative membrane filter system showed the presence of at least one mycobacterial colony in four out of five scopes after a 45-minute glutaraldehyde exposure.
Additional studies utilizing a standardized mycobacterial species, inoculum size, and suspension characteristics are recommended to delineate adequate duration of disinfectant exposure time.
传统上，内镜的高水平消毒是通过手动或自动清洗内镜，再加上在2%碱性戊二醛中浸泡10至20分钟来进行的。分枝杆菌属对戊二醛不太敏感，最近制造商建议将器械浸泡45分钟。由于担心内镜损坏、需要更多内镜，以及认为当前的清洗方法足够，我们对清洗过程各个阶段受分枝杆菌污染的内镜进行了前瞻性研究。
所有工作均在微生物实验室的层流罩下进行。五根胃肠镜被每毫升10⁸菌落形成单位（CFU/mL）的龟分枝杆菌污染，龟分枝杆菌是一种非典型分枝杆菌，其化学抗性与结核分枝杆菌相似，但感染潜力较小。在基线、手动清洗后、以及在酒精冲洗前后，分别在戊二醛浸泡10、20和45分钟后，对鞘管、活检通道和升降通道进行培养。
手动清洗使存活的分枝杆菌菌落平均减少4.7个对数10。对外科内镜表面以及气水阀的定性研究表明，在碱性戊二醛中暴露10分钟后未检测到生物体。通道的传统定量培养技术显示，五根内镜中有一根在暴露于戊二醛10分钟后仍有持续生长。酒精处理后，没有明显的菌落生长。相比之下，定量膜过滤系统显示，在戊二醛暴露45分钟后，五根内镜中有四根至少存在一个分枝杆菌菌落。
建议进行更多研究，采用标准化的分枝杆菌种类、接种量和悬浮特性，以确定消毒剂暴露时间的足够时长。
