The Ecological Dynamics of Fecal Contamination and Salmonella Typhi and Salmonella Paratyphi A in Municipal Kathmandu Drinking Water.
The Ecological Dynamics of Fecal Contamination and Salmonella Typhi and Salmonella Paratyphi A in Municipal Kathmandu Drinking Water.
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DOI：
10.1371/journal.pntd.0004346
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发表时间：
2016-01
影响因子：
3.8
通讯作者：
Baker S
中科院分区：
文献类型：
--
作者：
Karkey A;Jombart T;Walker AW;Thompson CN;Torres A;Dongol S;Tran Vu Thieu N;Pham Thanh D;Tran Thi Ngoc D;Voong Vinh P;Singer AC;Parkhill J;Thwaites G;Basnyat B;Ferguson N;Baker S
联合国可持续发展目标之一是到2030年实现普遍获得安全和负担得起的饮用水。这一目标与尼泊尔加德满都这样的地区最为相关。尼泊尔加德满都是南亚人口稠密的城市，流行地方性伤寒。为了了解加德满都水质对公共卫生的影响，我们在一年的时间里每周对10个水源的水样进行一系列化学和细菌学分析。此外，我们还旨在通过16S rRNA基因调查来检测伤寒的病原，并纵向评估微生物多样性。我们发现，大多数水源的化学和细菌污染超过了世卫组织的指导方针。对化学和细菌数据的进一步分析表明，特定地点的污染是高度局部的粪便污染的症状。发现降雨是这种粪便污染的关键驱动因素，与硝酸盐和伤寒沙门氏菌和副伤寒沙门氏菌a的证据相关，其中432个水样中分别有333个（77%）和303个（70%）检测到其DNA。16S rRNA基因调查勾勒出受污染水中粪便细菌的光谱，形成复杂的群落，再次显示出特定地点的时间特征。我们的数据表明，加德满都的市政用水是伤寒沙门氏菌和副伤寒沙门氏菌a型传播的主要媒介。这项研究首次对地方性伤寒环境下的水污染进行了广泛的时空调查，并暗示高度局部的人类排泄物是加德满都谷地水质差的主要原因。为了了解尼泊尔加德满都城市饮用水的生态，并测量导致伤寒的病原体（伤寒沙门菌和副伤寒沙门菌）的潜在暴露，我们在一年的时间里每周采集10个水源的水样，并对其进行全面的化学、细菌和分子分析。我们发现加德满都的饮用水显示出超过世卫组织指导方针的纵向粪便污染。水的化学成分表明了特定地点的污染概况，这可能是由人类粪便物质的局部污染造成的。我们还发现，在每个水样点全年都可以检测到伤寒沙门菌和甲型副伤寒沙门菌，但在季风之后达到峰值。微生物群分析（研究生物样本中细菌多样性的一种方法）显示，水受到了复杂的粪便细菌群的污染，这些细菌在地点和时间上再次表现出独特的特征。该研究表明，在加德满都的饮用水中可以纵向检测到伤寒沙门氏菌和甲型副伤寒沙门氏菌，这是对地方性伤寒环境下饮用水污染时空动态的首次重大调查。
One of the UN sustainable development goals is to achieve universal access to safe and affordable drinking water by 2030. It is locations like Kathmandu, Nepal, a densely populated city in South Asia with endemic typhoid fever, where this goal is most pertinent. Aiming to understand the public health implications of water quality in Kathmandu we subjected weekly water samples from 10 sources for one year to a range of chemical and bacteriological analyses. We additionally aimed to detect the etiological agents of typhoid fever and longitudinally assess microbial diversity by 16S rRNA gene surveying. We found that the majority of water sources exhibited chemical and bacterial contamination exceeding WHO guidelines. Further analysis of the chemical and bacterial data indicated site-specific pollution, symptomatic of highly localized fecal contamination. Rainfall was found to be a key driver of this fecal contamination, correlating with nitrates and evidence of S. Typhi and S. Paratyphi A, for which DNA was detectable in 333 (77%) and 303 (70%) of 432 water samples, respectively. 16S rRNA gene surveying outlined a spectrum of fecal bacteria in the contaminated water, forming complex communities again displaying location-specific temporal signatures. Our data signify that the municipal water in Kathmandu is a predominant vehicle for the transmission of S. Typhi and S. Paratyphi A. This study represents the first extensive spatiotemporal investigation of water pollution in an endemic typhoid fever setting and implicates highly localized human waste as the major contributor to poor water quality in the Kathmandu Valley. Aiming to understand the ecology of municipal drinking water and measure the potential exposure to pathogens that cause typhoid fever (Salmonella Typhi and Salmonella Paratyphi A) in Kathmandu, Nepal, we collected water samples from 10 water sources weekly for one year and subjected them to comprehensive chemical, bacteriological and molecular analyses. We found that Kathmandu drinking water exhibits longitudinal fecal contamination in excess of WHO guidelines. The chemical composition of water indicated site-specific pollution profiles, which were likely driven by localized contamination with human fecal material. We additionally found that Salmonella Typhi and Salmonella Paratyphi A could be detected throughout the year in every water sampling location, but specifically peaked after the monsoons. A microbiota analysis (a method for studying bacterial diversity in biological samples) revealed the water to be contaminated by complex populations of fecal bacteria, which again exhibited a unique profile by both location and time. This study shows that Salmonella Typhi and Salmonella Paratyphi A can be longitudinally detected in drinking water in Kathmandu and represents the first major investigation of the spatiotemporal dynamics of drinking water pollution in an endemic typhoid setting.