Orta de Velásquez María Teresa, Yáñez Noguez Isaura, Casasola Rodríguez Beatriz, Román Román Priscila Ivette
a Coordinación de Ingeniería Ambiental , Instituto de Ingeniería, Universidad Nacional Autónoma de México , Distrito Federal , Mexico.
Environ Technol. 2017 Mar;38(6):744-753. doi: 10.1080/09593330.2016.1210680. Epub 2016 Jul 26.
Helicobacter pylori is a pathogen bacteria associated with chronic gastritis, peptic ulceration, and gastric carcinoma. H. pylori has a spiral morphology, which under certain conditions of stress becomes a coccoid form. This type of morphology has been linked to a viable but non-culturable (VBNC) state, which is thought to allow its persistence in the environment. Membrane damage in VBNC H. pylori in water as a mechanism for inactivation using ozone (O) and chlorine disinfection has not been reported in the literature. In this paper, disinfection assays with ozone and chlorine were conducted to evaluate their effects on VBNC H. pylori cells. The use of fluorescent dyes such as propidium monoazide (PMA) coupled with quantitative real-time polymerase chain reactions produced results necessary to assess the viability of the microorganism and demonstrate the effect of each disinfectant on the bacterial count. Applying ozone showed a 5-log bacterial reduction using a disinfectant concentration and exposure time (CT) of 4 mg min/L. Chlorine disinfection for the same 5-log reduction required a higher CT value. Field emission scanning electron microscope images of ozone-treated VBNC H. pylori also showed severe cell damage. The use of PMA revealed that chlorine produced physical damage in the membrane in addition to the known inhibiting effect on cell enzymatic processes. These findings are important for the detection and control of VBNC H. pylori cells in drinking water systems.
幽门螺杆菌是一种与慢性胃炎、消化性溃疡和胃癌相关的致病细菌。幽门螺杆菌呈螺旋形态，在某些应激条件下会变成球形。这种形态与一种活的但不可培养（VBNC）状态有关，据认为这种状态使其能够在环境中持续存在。关于水中处于VBNC状态的幽门螺杆菌因臭氧（O）和氯消毒而导致膜损伤作为失活机制的情况，文献中尚未有报道。在本文中，进行了臭氧和氯的消毒试验，以评估它们对处于VBNC状态的幽门螺杆菌细胞的影响。使用诸如单叠氮碘化丙啶（PMA）等荧光染料结合定量实时聚合酶链反应得出了评估微生物活力以及证明每种消毒剂对细菌数量影响所需的结果。使用臭氧时，在消毒剂浓度和接触时间（CT）为4 mg·min/L的情况下，细菌数量减少了5个对数级。氯消毒要达到相同的5个对数级减少则需要更高的CT值。经臭氧处理的处于VBNC状态的幽门螺杆菌的场发射扫描电子显微镜图像也显示出严重的细胞损伤。使用PMA表明，氯除了对细胞酶促过程具有已知的抑制作用外，还会对膜造成物理损伤。这些发现对于饮用水系统中处于VBNC状态的幽门螺杆菌细胞的检测和控制具有重要意义。
