Simulation of the Fate of Faecal Bacteria in Estuarine and Coastal Waters Based on A Fractionated Sediment Transport Model

A two-dimensional depth-integrated numerical model is refined in this paper to simulate the hydrodynamics, graded sediment transport process and the fate of faecal bacteria in estuarine and coastal waters. The sediment mixture is divided into several fractions according to the grain size. A bed evolution model is adopted to simulate the processes of the bed elevation change and sediment grain size sorting. The faecal bacteria transport equation includes enhanced source and sink terms to represent bacterial kinetic transformation and disappearance or reappearance due to sediment deposition or re-suspension. A novel partition ratio and dynamic decay rates of faecal bacteria are adopted in the numerical model. The model has been applied to the turbid water environment in the Bristol Channel and Severn estuary, UK. The predictions by the present model are compared with field data and those by non-fractionated model.

Integrated site-specific quantification of faecal bacteria and detection of DNA markers in faecal contamination source tracking as a microbial risk tracking tool in urban Lake ecosystems

The presence of feacal-derived pathogens in water is responsible for several infectious diseases and deaths worldwide. As a solution, sources of fecal pollution in waters must be accurately assessed, properly determined and strictly controlled. However, the exercise has remained challenging due to the existing overlapping characteristics by different members of faecal coliform bacteria and the inadequacy of information pertaining to the contribution of seasonality and weather condition on tracking the possible sources of pollution. There are continued ef forts to improve the Faecal Contamination Source Tracking(FCST) techniques such as Microbial Source Tracking(MST). This study aimed to make contribution to MST by evaluating the efficacy of combining site specific quantification of faecal contamination indicator bacteria and detection of DNA markers while accounting for seasonality and weather conditions' eff ects in tracking the major sources of faecal contamination in a freshwater system(Donghu Lake, China). The results showed that the use of cyd gene in addition to lacZ and uidA genes differentiates E. coli from other closely related faecal bacteria. The use of selective media increases the pollution source tracking accuracy. BSA addition boosts PCR detection and increases FCST efficiency. Seasonality and weather variability also influence the detection limit for DNA markers.

Growth Characteristics of <i>Fuirena umbellata</i>in a Surface Flow Constructed Wetland and Its Influence in Nutrients and Faecal Bacteria Removal from Domestic Wastewater in Cameroon

Various configurations of vegetated bed systems with a variety of macrophytes have been tested experimentally in Cameroon, for the treatment of domestic wastewater. The aim of this work was to assess the growth and biomass production of Fuirena umbellata (Cyperaceae) and its potentials in the removal of faecal bacteria and nutrients from primarily treated domestic effluent. A wetland vegetated with this macrophyte and a non-vegetated wetland (control) were continuously fed with primarily treated domestic wastewater at an estimated loading rate of 205 Litres/day in dry and rainy seasons for two consecutive years. Physicochemical and microbiological parameters of the effluent were monitored at the inflow and outflows of the wetlands alongside with the growth and productivity attributes of the young plants during each season. The density of plants ranged in the wetland from 17 - 185 plants/m2 and from 11 - 146 plants/m2 respectively during the first and the second years. More biomasses were instead produced in the dry seasons than in the rainy seasons but with no significant differences observed. As for nutrients removal, higher efficiencies were observed in the vegetated wetland (45% - 73%) compared to the non-vegetated control (17% - 66%). Similar trends were observed for the faecal bacteria but with no significant differences between the seasons. However, the vegetated beds were significantly more efficient than the non-vegetated control in the reduction of many physicochemical parameters and faecal bacteria. This varied with the seasons.

Numerical Modelling Sediment-Bacteria Interaction Processes in the Severn Estuary

Faecal bacteria exist in both free-living and attached forms in estuarine waters. The deposition of sediments can take faecal bacteria out of the water column and to the bed. The sediments can subsequently be re-suspended to the water column, which can then lead to re-suspension of the faecal bacteria of the attached forms back to the water column. Therefore, the fate and transport of faecal bacteria is highly related to the governing sediment transport processes, particularly where these processes are significant, such as the Severn Estuary, UK. However, little attempt has been made to model such processes in terms of predicting the impact of the sediment fluxes on faecal bacteria levels. Details are given of the refinement of a numerical model of faecal bacteria transport, where the sediment transport processes are significant. After testing the sediment-bacteria interaction model favourably against known results in previous study, the model was applied to the Severn Estuary and Bristol Channel, UK, to investigate the impact of suspended sediment fluxes on the corresponding faecal bacteria transport processes. The model predictions have proved to be encouraging, with the results being compared to a traditional faecal bacteria modelling approach, where sediment bacteria interactions were not included. The new model provides improved predictions of faecal bacteria concentrations when sediment transport is included and for the Bristol Channel Severn Estuary it can be seen that the effects of the sediments on the bacterial levels in the water column can be significant.

通过体外发酵研究不同聚合度的大蒜多糖对人体肠道菌群的影响

主要研究了不同聚合度(DP)的大蒜多糖对人体肠道菌群生长的影响。通过模拟人体肠道厌氧环境,分别添加平均DP为11、14、16、21的大蒜多糖到发酵培养基中,并以添加菊糖、葡萄糖以及无碳源的发酵培养基为对照,接种人体粪悬液进行发酵。测定发酵24h后的pH值和残糖含量,并对总厌氧菌、肠球菌、拟杆菌、大肠杆菌、双歧杆菌、乳酸菌等主要肠道菌进行选择性培养测其活菌数。结果表明,阳性对照菊糖与各大蒜多糖发酵液的终pH值无显著差异;肠道微生物对平均DP为16、21的大蒜多糖的利用率较高;各样品发酵液中拟杆菌、肠球菌和大肠杆菌的菌数下降约0.36-1.05个数量级;4种大蒜多糖对双歧杆菌的增殖约2.2-4.1个数量级,其中平均DP为16、21的大蒜多糖增殖效果更佳,最高菌数可达7.74logCFU/mL发酵液。

树鼩粪便细菌分离培养与鉴定

目的了解人工饲养树鼩粪便菌群多样性,为树鼩的正常饲养繁殖和微生物质量控制标准化提供依据。方法随机采集10份树鼩粪便样品,利用有氧及厌氧培养基进行细菌分离培养,提取细菌基因组DNA后PCR扩增16SrRNA基因并测序鉴定。结果本实验从树鼩粪便样品中,经有氧培养分离鉴定出25株、12种细菌,经厌氧培养分离鉴定出25株、10种细菌,包括变形杆菌属、肠球菌属、埃希菌属、志贺菌属、葡萄球菌属、气单胞菌属、拉恩氏菌属、拉乌尔菌属、微小杆菌属、链球菌属、明串珠菌属。结论树鼩肠道好氧菌及厌氧菌具有丰富的种属多样性,普通变形杆菌群、费格森埃希菌群和屎肠球菌群可能是树鼩肠道的主要寄生菌群。

口服药品控制菌标准的研究

目的：以药品的不同卫生指标：大肠杆菌、粪大肠菌群、大肠菌群的检出率进行比较，为口服药品卫生标准的修订提供科学依据。方法：按中国药典和国标《食品卫生检验方法》进行检测。结果：以大肠菌群为卫生指标的检出率远高于大肠杆菌、粪大肠菌群；而粪大肠菌群的检出率为０。结论：以大肠菌群作为口服药品的控制菌较合理，将使药品有更高的安全性。

基于IL-6/STAT3信号通路探讨粪菌移植干预湿热蕴结型肠癌小鼠的作用机制

目的:研究IL-6/STATE3通路在粪菌移植(FMT)干预湿热蕴结型肠癌小鼠中的作用。方法:20只小鼠建立湿热蕴结型肠癌小鼠模型,并分为模型组和FMT组,另选10只为对照组。FMT组自造模后每日给予15 g/kg粪菌剂量灌肠处理,灌肠体积0.2 mL。对照组和模型组给予等体积生理盐水灌肠处理。1周后取直肠组织检测小鼠肿瘤体积、肿瘤质量;检测小鼠直肠组织中Ki-67的表达以及IL-6/STAT3信号通路活化情况。结果:相比于对照组,模型组Ki-67表达明显提升,IL-6/STAT3通路的活化程度较大(P<0.05);相比于模型组,FMT组肿瘤体积以及肿瘤质量显著减少,Ki-67表达明显降低,IL-6/STAT3通路的活化程度降低(P<0.05)。结论:FMT通过抑制IL-6/STATE3通路活化,抑制湿热蕴结型肠癌小鼠肿瘤细胞的增殖来发挥作用。

沉积物和悬浮颗粒物在岩溶水系统污染物衰减与运移中的作用(英文)

本文讨论了沉积物和悬浮颗粒物/胶体在岩溶水系统污染物衰减与运移中的作用,介绍了关于瑞士某岩溶水系统内颗粒物与微生物污染间关系的试验结果。该试验场包括一个接纳农田排水的落水洞及与其相连的两个泉,其中一个泉是供水水源地。利用便携式粒子计实时监测泉水中颗粒分布的变化情况,同时对浊度、总有机碳和其它参数进行连续监测;并对水中E型大肠菌群进行了分析。在暴雨过后,观测到了浊度的两种不同表现:在泉排泄量增加时,浊度最初表现为脉状水动力条件下岩溶系统内沉积物的二次运移;几天后观测到的浊度则表明水已从落水洞到了泉口,常常具有高的总有机碳、硝酸盐及E型大肠菌群。颗粒分布分析结果差异更大:早期的浊度是不同粒径颗粒物的混合,而后期的浊度更多的是由较细颗粒构成,因为大颗粒物已沉积在落水洞到泉口之间的岩溶系统内。E型大肠菌群与0.9～1.5μm颗粒物之间具有很好的相关性。因而较细颗粒的相对增加可应用于微生物污染"早期预报系统"。除了水污染,颗粒分布还可以帮助我们研究岩溶环境的其它问题,如土壤侵蚀。

Effect of Distance of Sanitary Pits on the Microbial and Heavy Metal Levels in Hand Dug Well Water Samples Consumed by People Living in Akwuke, Enugu South Local Government Area of Enugu State

Studies were carried out to assess the effect of distance of sanitary pits on the microbial and heavy metal levels in hand dug well water samples consumed by people living in Akwuke, Enugu South Local government area of Enugu State, using standard biochemical and spectrophotometric analysis. The well water samples were digested with aqua-regia and four heavy metals (Pb, Cd, Cu and Zn) were assayed in the well water samples at sampling distances of 3, 6 and 10 m respectively from the sanitary pits. The range of mean bacterial counts (cfu/g) for the four detected pathogenic bacteria; S. aureus, Klebsiella pnemeoniae, Echerichia coli and Salmonella enteritidis were 83 - 3730, 510 - 870, 50 - 2535 and 240 - 3420 Cfu/g at sampling distances of 3, 6 and 10 m respectively from the sanitary pits. The mean bacteria counts of the four detected pathogenic organisms in the well water sample at sampling distances of 3 and 6 m respectively from the sanitary pits were above the WHO recommended threshold limits for a safe drinking water. The mean bacterial counts of Salmonella enteritidis in the well water samples of sampling distance of 10 m from the sanitary pits was above the WHO recommended permissible limits. At sampling distances of 3, 6 and 10 m from the sanitary pits, the mean range of Pb, Cd, Cu and Zn in the well water samples were, 0.03 - 0.3, 0.02 - 0.05, 0.46 - 1.71 and 1.63 - 7.03 μg/g respectively. The mean levels of Pb and Cd in the well water samples at sampling distances of 3 and 6 m respectively from the sanitary pits were above their respective WHO recommended threshold limits. The mean heavy metals (Cd, Pb, Cu and Zn) in the well water samples at sampling distances of 3, 6, and 10 m respectively from the sanitary pits were statistically significant at p < 0.05.

454焦磷酸测序分析几种哺乳动物粪便细菌多样性

【目的】分析比较几种哺乳动物粪便细菌群落多样性,了解粪便细菌多样性与动物进化和食物的关系。【方法】采集6种哺乳动物粪便样品;提取总DNA;PCR扩增,获得16S rDNA V3标签片段;用454焦磷酸测序技术进行高通量测序;主要基于QIIME平台分析比较粪便细菌多样性。【结果】分析发现,厚壁菌门和拟杆菌门广泛存在于各样品中,并且占绝对优势。α多样性分析发现,杂食性的长臂猿、黑猩猩和川金丝猴的多样性最高,其次是肉食性的东北虎,来自熊科杂食性的亚洲黑熊和大熊猫的多样性最低。β多样性分析发现,白眉长臂猿、黑猩猩、川金丝猴几种灵长目动物粪便的菌群相似,而大熊猫菌、黑熊、孟加拉虎几种食肉目动物粪便细菌群相似但食肉动物孟加拉虎主要又因含梭杆菌门而区别于其他动物。【结论】动物粪便细菌优势类群明显;同种动物重复样本的相似性最高,各种动物多样性存在差异,但几种灵长类动物粪便细菌多样性更丰富;动物粪便细菌的组成和动物的进化及食物相关。本研究为哺乳动物粪便菌资源及后续研究提供了借鉴。

2012—2021年我国护理领域粪菌移植相关文献的计量学研究

目的了解我国护理领域粪菌移植研究的现况、发展趋势,并与我国临床领域的相关研究发展情况进行对比,为后续研究的开展提供指导和借鉴。方法采用文献计量学方法,对万方数据、中国知网、维普三大数据库中2012—2021年粪菌移植相关文献进行内容分析。结果根据纳入排除标准,共纳入粪菌移植相关文献881篇,其中护理领域相关文献54篇,临床领域的相关文献827篇。自2013年开始有护理领域粪菌移植相关研究见刊后,发文量呈缓慢增加后逐渐下降趋势。发文量最多的为江苏省,发文15篇占27.8%;获基金支持的护理领域粪菌移植论文38篇,其中国家级科研基金资助9篇。结论我国粪菌移植相关研究近10年发展迅速,已形成系列研究,但护理领域的粪菌移植研究的深度和广度均不足,后期需更多研究者加入,加强医护间合作交流,制订具有护理特色的粪菌移植相关内容,增加护理粪菌移植研究的广度和深度。