应用rep-PCR微生物源方法追踪夏秋季桂五水库粪便污染来源

目的：应用重复序列聚合酶链反应（rep-PCR）微生物源追踪方法，追踪夏秋季江苏桂五水库的粪便污染来源追踪。方法：采集已知来源的人和动物粪便标本以及夏秋两季水样标本，分离并确认指示菌大肠杆菌，以BOXAIR为引物进行PCR扩增；用Bionumerics4．0软件对rep-PCR基因指纹图进行判别分析和多元方差分析并计算各源种类的正确归类率。结果：10、5、3和2分类法平均正确归类率分别为68．13％、74．76％、82．36％和86．03％。判别分析和多元方差分析结果显示rep—PCR基因指纹图能将已知源不同来源指示菌区分开。水样中主要粪便污染来源为人、鸡和牛。结论：建立的rep—PCR微生物源追踪方法能较好地区分水体中指示菌的不同来源，水体标本监测显示桂五水库粪便污染来源种类多，其中人、鸡和牛相对较多，提示应对桂五水库地区加强人、家禽和家畜动物粪便的无害化管理。     

应用不同微生物源追踪方法追踪水库中粪便污染来源

目的:用两种不同的微生物源追踪(Microbial source tracking,MST)方法对江苏省盱眙县桂五水库粪便污染来源进行追踪。方法:于春、夏、秋、冬4季分别采集水库周边已知来源粪便标本,分离大肠埃希菌并作为指示菌,分别建立已知源指示菌细菌基因组重复序列PCR(repetitive Extragenic Palindromic-Polymerase chain reaction,rep-PCR)特征指纹库和已知源指示菌抗生素敏感性(Antibiotic Resistance Analysis,ARA)数据库,并分别用统计分析及试验设计软件(JMP7.0软件)和基因聚类分析软件(Bionumerics 4.0软件)计算平均正确归类率(Average Rate of Correct Classification,ARCC),以检验各自的宿主来源区分效果。同期采集水样,膜过滤法分离并确认指示菌,分别进行rep-PCR扩增和ARA试验,并分别与已知源指示菌rep-PCR特征指纹库和ARA数据库进行统计学比对,判断桂五水库中粪便污染来源。结果:将已知源指示菌rep-PCR特征指纹库和ARA数据库分别分为2、...     

rep-PCR基因指纹图微生物源追踪方法建立的研究

[目的]建立重复序列聚合酶链反应(rep-PCR)微生物源追踪方法,应用于淮河流域某水库的粪便污染来源追踪.[方法]采集已知来源的人和动物粪便标本以及水样标本,分离并确认指示菌大肠杆菌,以BOXA1R为引物进行PCR扩增;用Bionumerics 4.0软件对rep-PCR基因指纹图进行判别分析和多元方差分析并计算各源种类的正确归类率.[结果]2分类、4分类和10分类的正确归类率分别为:85.60%、79.20%和70.98%.判别分析和多元方差分析结果显示rep-PCR基因指纹图能将已知源不同来源指示菌区分开.水样中主要粪便污染来源为猪、鸡和人.[结论]建立的rep-PCR微生物源追踪方法能较好地区分水体中指示菌的不同来源,该方法的建立为查找水体中粪便污染来源以及水体治理提供了新技术.     

微生物源追踪技术在不同污染水体中的应用评价

目的建立南京秦淮河上游中山河和淮河流域桂五水库的微生物源追踪抗生素敏感性分析(antibiotic resistance analysis,ARA)数据库,追踪水体中的污染来源,探讨该方法在不同水体中追踪微生物污染源的应用价值。方法采集目标水体周边自然村中人、家畜、家禽等的粪便标本及生活和工业污水排放口直接排放的污水,分离并确认指示菌,建立已知源微生物源追踪数据库。按计划采集未知源水样,分离指示菌并使用J MP7.0软件进行污染源追踪及效果评价。结果秦淮河上游中山河水体污染源主要为工业及生活污水和狗的粪便污染。淮河流域桂五水库环境水污染源则主要为人和羊的粪便污染。结论微生物源追踪方法不仅可以应用于原生态水体,而且可以应用于受生活、工业双重污染水体的微生物污染源追踪,均能取得较好的效果。     

微生物源追踪技术在不同污染水体中的应用评价

目的建立南京秦淮河上游中山河和淮河流域桂五水库的微生物源追踪抗生素敏感性分析（antibiotic resistance analysis,ARA）数据库,追踪水体中的污染来源,探讨该方法在不同水体中追踪微生物污染源的应用价值。方法采集目标水体周边自然村中人、家畜、家禽等的粪便标本及生活和工业污水排放口直接排放的污水,分离并确认指示菌,建立已知源微生物源追踪数据库。按计划采集未知源水样,分离指示菌并使用JMP7．0软件进行污染源追踪及效果评价。结果秦淮河上游中山河水体污染源主要为工业及生活污水和狗的粪便污染。淮河流域桂五水库环境水污染源则主要为人和羊的粪便污染。结论微生物源追踪方法不仅可以应用于原生态水体,而且可以应用于受生活、工业双重污染水体的微生物污染源追踪,均能取得较好的效果。     

抗生素敏感性微生物源追踪方法建立

目的 建立抗生素敏感性微生物源追踪方法,以分析淮河流域某水库粪便污染来源.方法 采集水库周边已知来源粪便标本,分离指示菌,接种至含抗生素的培养基,筛选能区分不同来源指示菌的抗生素浓度,用YMP7.0软件进行判别分析检验效果.同时采集水样进行粪便污染来源追踪.结果 筛选的不同抗生素及其浓度能将已知来源指示菌正确归类率分别为93.05%(2分类)、85.75%(3分类)和78.53%(9分类).100株指示菌中有58株来自家畜,25株来自家禽,11株来自狗,4株来自人,2株来自野生动物.水样标本中主要的粪便污染来源为猪、牛、鸡,分别占水样分离指示菌总数的36%,17%和15%.结论 所筛选的抗生素浓度均能较好地区分指示菌的不同来源,该方法的建立可以为查找水体粪便污染来源以及水体治理提供参考与帮助.     

细菌源追踪技术及进展

细菌源追踪(Bacterial Source Tracking,BST)也称为微生物源追踪(Microbial Source Tracking,MST),是根据水域中指示菌追踪污染物来源,可以将非点源污染转化为点源污染,从而方便进行水环境监测和控制的一门技术。最早由弗吉尼亚理工学院George M·Sim-mons Jr教授提出,将其应用     

基于分离培养的微生物源追踪方法的研究进展

微生物源追踪是从水体粪便污染研究开始发展起来,该文对基于分离培养的微生物源追踪部分方法 的原理、应用及进展进行了综述.随着研究技术的不断发展,微生物源追踪的研究范围也逐渐扩大,包括食物、空气等.众多的方法 中,基因型方法 在未来微生物源追踪研究中会有更广阔的应用前景.     

肠道厌氧菌在水体粪便污染源及病原微生物监测中的应用

动物粪便直接排放不仅会造成水体中氮磷含量的升高,同时也造成了病原微生物的传播以至危害人体健康。因此,对水体中生物性污染来源的确定是采取有效防治措施的前题。厌氧菌是动物体肠道的主要菌种,而且部分菌种具有高度的宿主特异性,同时厌氧菌与某些病原微生物在自然环境中具有一定的关联性,因此是水体粪便污染源的良好指示菌。该文对主要的肠道厌氧菌进行介绍,并就其与常见的病原微生物在水体中的生存状况及其关联进行概述。     

微生物源示踪技术在非点源粪便污染源检测中的应用

目的 探究以细菌基因组重复序列PCR技术(repetitive extragenic palindromic consensus sequence-PCR,REP-PCR)为手段的微生物源示踪技术对鉴别非点源污染中养殖动物粪便污染来源的应用价值.方法 采用针对大肠杆菌优化的分离与生化鉴定方法,从大连金州湾沿岸采集猪、牛...     

Microbiological analysis of mineral water and drinking water of reservoir supplies,Brazil

The aim of this study was to evaluate the microbiological quality of different commercial mineral water brands, wells and reservoir supplies in surrounding areas of the city of Marília, Brazil, to determine the amount of total and fecal coliforms. Eighteen samples of each source (mineral and reservoir supplies) were analyzed using Colilert Technique in cellophane. The results revealed that one sample of mineral water and one sample collected from the reservoir supply had been contaminated by a bacterium of the total coliform group, and there were found one bacterium/100 ml of water. None of the water samples showed contamination by fecal coliforms.     

Fecal water genotoxicity is predictive of tumor-preventive activities by inulin-like oligofructoses, probiotics (Lactobacillus rhamnosus and Bifidobacterium lactis), and their synbiotic combination

The measurement of fecal water genotoxicity in human colon cells could be a useful biomarker to study effects of diet in the colon. Here we assessed aqueous fecal extracts of samples from a chronic study with rats fed prebiotics, probiotics, and their combination. Treatments were maltodextrins (controls), inulin/oligofructoses (prebiotic), Lactobacillus rhamnosus, and Bifidobacterium lactis (probiotics) or both (synbiotic). Azoxymethane (AOM) was administered to initiate tumors. Rat feces were collected at 0 and 10 days and 2, 4, and 8 mo, and cecal contents were collected at 8 mo. Aqueous phases were prepared and tested for genotoxicity in HT29 colon cells using the comet assay. The studied types of intervention reduced fecal and cecal genotoxicity. DNA damage by samples from AOM-treated, tumor-free rats was significantly lower than from tumor-bearing animals, especially after 4 mo of synbiotic and prebiotic interventions. Inulin-based diets reduced exposure to genotoxins in the feces, directly reflecting the reported reduction of tumor incidence in these animals. Evidence is provided for the validity of this measurement as a biomarker of chemoprevention because 1) fecal water genotoxicity reflected genotoxic exposure in the cecum, 2) tumor incidence and fecal genotoxicity were directly related, and 3) these interventions reduced tumor risks by reducing exposure to genotoxins in the gut.     

Physicochemical and bacteriological assessment of water quality at the Ross Barnett reservoir in central Mississippi.

The Ross Barnett Reservoir serves as a source of water supply for the city of Jackson, Mississippi, U.S.A. and is an important site for recreational activities for many residents of Mississippi counties. A broad spectrum of illness is associated with water-contact activities like bathing and swimming in recreational waters. In the present research, we assessed the bacteriological quality of water in the Ross Barnett Reservoir and compared the levels of bacteria with the recommended criteria for public health protection. From June 12, 1999 to October 2, 1999, we collected water samples weekly from two different sites in the reservoir and tested them for the following bacteriological parameters: heterotrophic plate counts, total coliforms, fecal coliforms, and fecal streptococci. The samples were also tested for basic physical and chemical characteristics of water. The results of the study indicate that the respective mean concentrations of bacteria (colony forming units per 100 mL of water) in water samples collected from the reservoir were 5.6 x 10(6)+/-1.5 x 10(6) (heterotrophic plate counts), 4.5 x 10(4) +/- 5.3 x 10(4) (total coliforms), 5.0 x 10(2) +/- 1.6 x 10(2) (fecal coliforms), and 9.1x10(1)+/-7.3x10(1) (fecal streptococci). The values of all physical and chemical parameters were at acceptable levels. The bacterial densities, however, often exceeded federal/state guidelines by several orders of magnitude, raising considerable public health concerns. Steps should therefore be taken to develop and implement strategies to improve the water quality and to reduce or eliminate the potential health risks associated with water-contact activities in the Ross Barnett Reservoir.     

Gilthead seabream (Sparus aurata) as carriers of SHV-12 and TEM-52 extended-spectrum beta-lactamases-containing Escherichia coli isolates

In recent years, bacterial resistance to beta-lactam antibiotics has risen dramatically in Escherichia coli isolated from animals that could pass through the food chain to humans. One hundred eighteen fecal samples of Sparus aurata were tested for extended-spectrum beta-lactamase (ESBL)-containing E. coli recovery. Susceptibility to 16 antimicrobial agents was performed by disk diffusion. ESBL-phenotypic detection was carried out by double-disk test, and the presence of genes encoding TEM, OXA, SHV, and CTX-M type beta-lactamases was studied by polymerase chain reaction and sequencing. The detection of other antimicrobial resistance mechanisms and phylogenetic groups was also performed in recovered isolates as well as their clonal diversity by pulsed-field gel electrophoresis. Five of the 118 fecal samples harbored ESBL-positive E. coli isolates (4.2%), and one isolate per sample was completely characterized. These five ESBL-positive E. coli isolates contained the bla(TEM-52) or bla(SHV-12) genes, as well as a variety of other resistance genes (cmlA, tetA, aadA, sul1, sul2, and sul3). Four isolates harbored class 1 integrons with the following gene cassettes in their variable region: dfrA1 + aadA1 (one isolate) and sat + psp + aadA2 (three isolates). Four unrelated pulsed-field gel electrophoresis patterns were identified among the five ESBL-positive isolates, and they were ascribed to phylogroups A and B1. The intestinal tract of S. aurata might constitute a reservoir of ESBL-producing E. coli isolates.     

Comparative study of endogenous fecal fatty acids in germ-free and conventional rats.

The effects of gastrointestinal flora on the quantitative and qualitative aspects of "endogenous" fecal fatty acid excretion were studied in the rat using germ-free (GF) and conventional (CVL) animals, lipid-free diet and open-tubular gas-liquid chromatography. Gastrointestinal flora slightly increased endogenous excretion of fatty acids. Analysis of fatty acids from different fecal lipid fractions showed that the presence of a microflora in the gastrointestinal tract extensively modified the qualitative aspects of endogenous fecal fatty acid spectra. In total endogenous fecal lipids, concentrations of mono and polyunsaturated fatty acids (from C16 to C22) were 3.5 times higher in GF rats, while concentrations of even-numbered and saturated fatty acids were 1.5 times higher in CVL rats. Odd-numbered fatty acids (from C11:10 to C2:0) represented 6.5% of total endogenous fecal fatty acids in CVL rats vensus 1.5% in GF rats. Branched-chain fatty acid (even-and-odd-numbered, iso and anteiso) concentrations were 12.9% in CVL rats versus 2.0% in GF rats. Results clearly showed that the gastrointestinal flora was the main source of odd-numbered fatty acids and branched-chain fatty acids in endogenous fecal lipids. However, a secondary source may also exist since these fatty acids represented 3.5% of the total endogenous fatty acids in GF rats.     

Chicken as reservoir for extraintestinal pathogenic Escherichia coli in humans, Canada

We previously described how retail meat, particularly chicken, might be a reservoir for extraintestinal pathogenic Escherichia coli (ExPEC) causing urinary tract infections (UTIs) in humans. To rule out retail beef and pork as potential reservoirs, we tested 320 additional E. coli isolates from these meats. Isolates from beef and pork were significantly less likely than those from chicken to be genetically related to isolates from humans with UTIs. We then tested whether the reservoir for ExPEC in humans could be food animals themselves by comparing geographically and temporally matched E. coli isolates from 475 humans with UTIs and from cecal contents of 349 slaughtered animals. We found genetic similarities between E. coli from animals in abattoirs, principally chickens, and ExPEC causing UTIs in humans. ExPEC transmission from food animals could be responsible for human infections, and chickens are the most probable reservoir.