Kaelin M B, Kuster S P, Hasse B, Schulthess B, Imkamp F, Halbe M, Sander P, Sax H, Schreiber P W
Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich and University of Zurich, Zurich, Switzerland.
Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland; National Reference Centre for Mycobacteria, Zurich, Switzerland.
J Hosp Infect. 2020 Mar 6. doi: 10.1016/j.jhin.2020.03.006.
The international outbreak of cardiac surgery-associated Mycobacterium chimaera infections was traced back to infectious aerosols originating from contaminated water reservoirs of heater-cooler devices (HCD). In general, nontuberculous mycobacteria (NTM) frequently colonize water systems and can contaminate medical devices. Data on detection of NTM other than M. chimaera in samples gathered from HCDs are scarce. The present study summarizes prospective mycobacterial surveillance of five HCDs over more than four years.
A cohort of five, in 2014 factory-new acquired, LivaNova 3T (London, UK) HCDs were prospectively followed. Until mid-April 2014 HCDs were maintained according to the manufacturer's recommendations, subsequently according to an intensified in-house protocol including exhaust air evacuation. Mycobacterial surveillance cultures consisted of monthly water samples gathered from patient and cardioplegia circuits, as well as airflow samples.
Out of 441 water samples, 170 (38.6%) revealed NTM growth. The most frequently detected NTM were Mycobacterium chimaera (n=120 (67.4%)), Mycobacterium gordonae (n=35 (19.7 %)), and Mycobacterium paragordonae (n=17 (9.6%)). Growth of NTM, M. chimaera and M. paragordonae was significantly more common in water samples derived from the patient than the cardioplegia circuit of the HCD. Three (2.0%) out of 150 air samples grew NTM.
Growth of NTM in HCD water samples was frequent. Diverse NTM species were detected, with M. chimaera being most common. The majority of air samples remained negative. The relevance of NTM other than M. chimaera contaminating HCDs is poorly defined, but a recent report on a HCD-associated outbreak with Mycobacterium abscessus confirms a potential threat.
心脏手术相关的嵌合体分枝杆菌感染的国际疫情可追溯至来自热交换水箱（HCD）受污染储水器产生的感染性气溶胶。一般而言，非结核分枝杆菌（NTM）常定植于水系统并可污染医疗设备。从HCD采集的样本中检测除嵌合体分枝杆菌之外的NTM的数据很少。本研究总结了对5台HCD超过四年的前瞻性分枝杆菌监测情况。
对2014年购置的5台全新的LivaNova 3T（英国伦敦）HCD进行前瞻性随访。2014年4月中旬之前，HCD按照制造商的建议进行维护，之后按照强化的内部方案进行维护，包括排出废气。分枝杆菌监测培养包括每月从患者和心脏停搏液回路采集的水样以及气流样本。
在441份水样中，170份（38.6%）显示有NTM生长。最常检测到的NTM是嵌合体分枝杆菌（n = 120（67.4%））、戈登分枝杆菌（n = 35（19.7%））和副戈登分枝杆菌（n = 17（9.6%））。NTM、嵌合体分枝杆菌和副戈登分枝杆菌在源自患者的HCD水样中的生长明显比心脏停搏液回路中的水样更常见。150份空气样本中有3份（2.0%）生长有NTM。
HCD水样中NTM生长频繁。检测到多种NTM菌种，其中嵌合体分枝杆菌最为常见。大多数空气样本为阴性。除嵌合体分枝杆菌之外的NTM污染HCD的相关性尚不明确，但最近一份关于HCD相关脓肿分枝杆菌暴发的报告证实了潜在威胁。
