Department of Public Health and Pediatrics, University of Turin, Italy.
Department of Public Health and Pediatrics, University of Turin, Italy.
J Hosp Infect. 2020 Nov;106(3):585-593. doi: 10.1016/j.jhin.2020.08.023. Epub 2020 Sep 1.
Heater-cooler units (HCUs) used during cardiopulmonary bypass may become colonized with non-tuberculous mycobacteria (NTM), including Mycobacterium chimaera. Recently, a worldwide investigation conducted in hospitalized infected patients has detected M. chimaera in several Stockert 3T HCUs manufactured by LivaNova.
Microbiological surveillance on Stockert 3T (LivaNova) and Maquet HCU40 (Getinge) devices as well as an evaluation of the efficacy of their recommended decontamination protocols.
A total of 308 water samples were collected from 29 HCUs: 264 samples were collected from 17 Stockert 3T HCUs and 44 samples from 12 Maquet HCU40 devices. Samples were tested for total viable counts (TVCs) at both 22 and 36°C, Pseudomonas aeruginosa, coliform bacteria, and NTM. The microbiological surveillance began in June 2017 and ran until October 2019.
A total of 308 HCU water samples were analysed, 65.5% of which yielded NTM. The most frequently colonized device with NTM was the Stockert 3T (88.2%), with a frequency of positive samples of 59.5% (157/264). The Maquet HCU40 devices less frequently yielded NTM (33.3%), with a frequency of positive water samples of 13.6% (6/44). Disinfection procedures were effective in reducing TVCs of bacteria with the exception of NTM species. NTM were detected in both pre-disinfection (50.1%) and post-disinfection (55.7%) samples, and no significant association was found between disinfection and NTM results both in Stockert 3T and Maquet HCU40 devices.
This study suggests that manufacturers' procedures for disinfection are ineffective and/or inadequate. Until effective disinfection protocols become available, the only way to minimize the risk of NTM contamination is to closely monitor the water quality in the HCU, keep it as clean as possible, and treat it like any other biohazardous material.
体外循环期间使用的热交换器可能会被非结核分枝杆菌（NTM）定植，包括 Chimera 分枝杆菌。最近，一项在住院感染患者中进行的全球调查在几家由 LivaNova 生产的 Stockert 3T 热交换器中检测到了 Chimera 分枝杆菌。
对 Stockert 3T（LivaNova）和 Maquet HCU40（Getinge）设备进行微生物监测，并评估其推荐的去污方案的效果。
从 29 个热交换器中采集了 308 个水样：从 17 个 Stockert 3T 热交换器中采集了 264 个水样，从 12 个 Maquet HCU40 设备中采集了 44 个水样。对水样进行总活菌计数（TVC）检测，检测温度分别为 22°C 和 36°C，同时还检测了铜绿假单胞菌、大肠菌群和 NTM。微生物监测于 2017 年 6 月开始，一直持续到 2019 年 10 月。
共分析了 308 个热交换器水样，其中 65.5%的水样含有 NTM。最常被 NTM 定植的设备是 Stockert 3T（88.2%），阳性样本的频率为 59.5%（157/264）。Maquet HCU40 设备较少产生 NTM（33.3%），阳性水样的频率为 13.6%（6/44）。消毒程序可有效降低细菌的 TVC，但不能有效降低 NTM 。在消毒前（50.1%）和消毒后（55.7%）的样本中均检测到了 NTM，且在 Stockert 3T 和 Maquet HCU40 设备中，消毒与 NTM 结果之间均未发现显著关联。
本研究表明，制造商的消毒程序无效且/或不充分。在有效消毒方案问世之前，将 NTM 污染风险降至最低的唯一方法是密切监测热交换器的水质，尽可能保持其清洁，并将其视为任何其他生物危害物质。
