Nguyen Huong Thi Mai, Le Quynh Thi Phuong, Garnier J, Janeau J-L, Rochelle-Newall E
Institute of Natural Product Chemistry, Viet Nam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay, Hanoi, Viet Nam.
Institut de Recherche pour le Développement (IRD), iEES -Paris, UMR 242, Centre IRD Nord, 32 avenue Henri Varagant, Bondy, F-93143, France.
Sci Rep. 2016 Feb 12;6:21644. doi: 10.1038/srep21644.
The Red River is the second largest river in Viet Nam and constitutes the main water source for a large percentage of the population of North Viet Nam. Here we present the results of an annual survey of Escherichia coli (EC) and Total Coliforms (TC) in the Red River basin, North Viet Nam. The objective of this work was to obtain information on faecal indicator bacteria (FIB) numbers over an annual cycle and, secondly, to determine the die-off rates of these bacterial indicators. Monthly observations at 10 stations from July 2013-June 2014 showed that TC and EC reached as high as 39100 cfu (colony forming units) 100 ml(-1) and 15300 colonies 100 ml(-1), respectively. We observed a significant seasonal difference for TC (p < 0.05) with numbers being higher during the wet season. In contrast, no significant seasonal difference was found for EC. The FIB die-off rates ranged from 0.01 d(-1) to a maximum of 1.13 d(-1) for EC and from 0.17 d(-1) to 1.33 d(-1) for TC. Die-off rates were significantly higher for free bacteria than for total (free + particle attached) bacteria, suggesting that particle attachment provided a certain level of protection to FIB in this system.
红河是越南第二大河流，是越南北部很大一部分人口的主要水源。在此，我们展示了对越南北部红河流域大肠杆菌（EC）和总大肠菌群（TC）的年度调查结果。这项工作的目的，一是获取关于粪便指示菌（FIB）数量在一年周期内的信息，二是确定这些细菌指示菌的消亡率。2013年7月至2014年6月在10个站点进行的月度观测表明，TC和EC分别高达39100 cfu（菌落形成单位）/100 ml(-1)和15300个菌落/100 ml(-1)。我们观察到TC存在显著的季节差异（p < 0.05），雨季的数量更高。相比之下，EC未发现显著的季节差异。FIB的消亡率范围为，EC从0.01 d(-1)到最高1.13 d(-1)，TC从0.17 d(-1)到1.33 d(-1)。游离细菌的消亡率显著高于总细菌（游离 + 附着在颗粒上的细菌），这表明颗粒附着为该系统中的FIB提供了一定程度的保护。
