Nocker Andreas, Cheswick Ryan, Dutheil de la Rochere Pierre-Marie, Denis Matthieu, Léziart Tangui, Jarvis Peter
a Cranfield Water Science Institute, School of Water, Environment and Energy , Cranfield University , Cranfield , Bedfordshire , UK.
b IWW Water Centre ; Mülheim an der Ruhr , Germany.
Environ Technol. 2017 Apr;38(7):891-900. doi: 10.1080/09593330.2016.1262463. Epub 2016 Dec 5.
Flow cytometry is increasingly employed by drinking water providers. Its use with appropriate fluorescent stains allows the distinction between intact and membrane-damaged bacteria, which makes it ideally suited for assessment of disinfection efficiency. In contrast to plate counting, the technology allows the visualization of the gradual loss of membrane integrity. Although this sensitivity per se is very positive, it creates the problem of how this detailed viability information compares with binary plate counts where a colony is either formed or not. Guidelines are therefore needed to facilitate interpretation of flow cytometry results and to determine a degree of membrane damage where bacteria can be considered 'dead'. In this study we subjected Escherichia coli and environmental microorganisms in real water to increasing chlorine concentrations. Resulting flow cytometric patterns after membrane integrity staining were compared with culturability and in part with redox activity. For laboratory-grown bacteria, culturability was lost at lower disinfectant concentrations than membrane integrity making the latter a conservative viability parameter. No recovery from chlorine was observed for four days. For real water, loss of membrane integrity had to be much more substantial to completely suppress colony formation, probably due to the heterogenic composition of the natural microbial community with different members having different susceptibilities to the disinfectant.
流式细胞术越来越多地被饮用水供应商所采用。将其与适当的荧光染料结合使用，可以区分完整细菌和膜受损细菌，这使其非常适合用于评估消毒效率。与平板计数不同，该技术可以直观地显示膜完整性的逐渐丧失。尽管这种敏感性本身是非常积极的，但它带来了一个问题，即这种详细的生存能力信息与二元平板计数（菌落要么形成要么不形成）相比如何。因此，需要指南来促进对流式细胞术结果的解释，并确定细菌可被视为“死亡”时的膜损伤程度。在这项研究中，我们将大肠杆菌和实际水中的环境微生物置于不断增加的氯浓度环境中。将膜完整性染色后得到的流式细胞术图谱与可培养性进行比较，部分还与氧化还原活性进行比较。对于实验室培养的细菌，在消毒剂浓度低于导致膜完整性丧失的浓度时，可培养性就已丧失，这使得膜完整性成为一个保守的生存能力参数。四天内未观察到从氯损伤中恢复的情况。对于实际水，膜完整性的丧失必须更加严重才能完全抑制菌落形成，这可能是由于天然微生物群落的异质性组成，不同成员对消毒剂的敏感性不同。
