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Alexandria B Boehm - One of the best experts on this subject based on the ideXlab platform.
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application of molecular source tracking and mass balance approach to identify potential sources of fecal Indicator Bacteria in a tropical river
PLOS ONE, 2020Co-Authors: Kevan M Yamahara, Rachelle S Thompson, Daniel P Keymer, Blythe A Layton, Sarah P Walters, Matt Rosener, Alexandria B BoehmAbstract:Microbial source tracking and a mass balance approach were used to identify sources of fecal Indicator Bacteria (FIB) in the Hanalei River, Kaua’i, Hawai’i. Historically, concentrations enterococci and Clostridium perfringens were significantly higher during storm flows compared to non-storm flows in the Hanalei River, and correlated to total suspended solids in the river. During targeted dry weather studies, the Hanalei River bed sediments and streambank soils were documented to harbor E. coli, enterococci, and the human- and pig-specific fecal markers in Bacteroidales, suggesting that sediments and soils may be potential sources of these microorganisms to the Hanalei river. The human-specific marker in Bacteroidales was four times as likely to be detected in sediment and soil samples as in water samples. Furthermore, the occurrence of host-specific source tracking markers is indicative that a portion of FIB present in the Hanalei River are of fecal origin. A mass balance approach was used to explore causes of observed FIB loadings and losses along different reaches of the river. Resuspension or deposition of FIB-laden river sediments cannot account for changes in E. coli and enterococci concentrations along the river during dry weather. Additionally, losses due to Bacterial inactivation were insignificant. Groundwater and ditches draining agricultural and urban lands were shown to provide sufficient FIB fluxes to account for the observed loads along some river reaches. The presence of the human-specific Bacteroidales marker in the river water, sediments and adjacent soils, as well as the presence of the human enterovirus marker in the water, suggests that there is widespread human fecal contamination in the Hanalei River that is likely a result of nearby wastewater disposal systems.
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Engineering Solutions to Improve the Removal of Fecal Indicator Bacteria by Bioinfiltration Systems during Intermittent Flow of Stormwater
2016Co-Authors: Sanjay K. Mohanty, Kara L Nelson, Andrew A. Torkelson, Hanna Dodd, Alexandria B BoehmAbstract:Bioinfiltration systems facilitate the infiltration of urban stormwater into soil and reduce high flow events and flooding. Stormwater carries a myriad of pollutants including fecal Indicator Bacteria (FIB). Significant knowledge gaps exist about the ability of bioinfiltration systems to remove and retain FIB. The present study investigates the ability of model, simplified bioinfiltration systems containing quartz sand and iron oxide-coated quartz sand (IOCS) to remove two FIB (Enterococcus faecalis and Escherichia coli) suspended in synthetic stormwater with and without natural organic matter (NOM) as well as the potential for accumulated FIB to be remobilized during intermittent flow. The experiments were conducted in two phases: (1) the saturated columns packed with either sand or IOCS were contaminated by injecting stormwater with Bacteria followed by injection of sterile stormwater and (2) the contaminated columns were subjected to intermittent infiltration of sterile stormwater preceded by a pause during which columns were either kept saturated or drained by gravity. During intermittent flow, fewer Bacteria were released from the saturated column compared to the column drained by gravity: 12% of attached E. coli and 3% of attached Ent. faecalis were mobilized from the drained sand column compared to 3% of attached E. coli and 2% attached Ent. faecalis mobilized from the saturated sand column. Dry and wet cycles introduce moving air–water interfaces that can scour Bacteria from grain surfaces. During intermittent flows, less than 0.2% of attached Bacteria were mobilized from IOCS, which bound both Bacteria irreversibly in the absence of NOM. Addition of NOM, however, increased Bacterial mobilization from IOCS: 50% of attached E. coli and 8% of attached Ent. faecalis were released from IOCS columns during draining and rewetting. Results indicate that using geomedia such as IOCS that promote irreversible attachment of Bacteria, and maintaining saturated condition, could minimize the mobilization of previous attached Bacteria from bioinfiltration systems, although NOM may significantly decrease these benefits
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Sunlight inactivation of fecal Indicator Bacteria in open-water unit process treatment wetlands: Modeling endogenous and exogenous inactivation rates
Water Research, 2015Co-Authors: Mi T. Nguyen, Justin T. Jasper, Alexandria B Boehm, Kara L NelsonAbstract:A pilot-scale open-water unit process wetland was monitored for one year and found to be effective in enhancing sunlight inactivation of fecal Indicator Bacteria (FIB). The removal of Escherichia coli and enterococci in the open-water wetland receiving non-disinfected secondary municipal wastewater reached 3 logs and 2 logs in summer time, respectively. Pigmented enterococci were shown to be significantly more resistant to sunlight inactivation than non-pigmented enterococci. A model was developed to predict the inactivation of E.coli, and pigmented and non-pigmented enterococci that accounts for endogenous and exogenous sunlight inactivation mechanisms and dark processes. Endogenous inactivation rates were modeled using the sum of UVA and UVB irradiance. Exogenous inactivation was only significant for enterococci, and was modeled as a function of steady-state singlet oxygen concentration. The rate constants were determined from lab experiments and an empirical correction factor was used to account for differences between lab and field conditions. The model was used to predict removal rate constants for FIB in the pilot-scale wetland; considering the variability of the monitoring data, there was general agreement between the modeled values and those determined from measurements. Using the model, we estimate that open-water wetlands at 40° latitude with practical sizes can achieve 3-log (99.9%) removal of E.coli and non-pigmented enterococci throughout the year [5.5ha and 7.0ha per million gallons of wastewater effluent per day (MGD), respectively]. Differences in sunlight inactivation rates observed between pigmented and non-pigmented enterococci, as well as between lab-cultured and indigenous wastewater Bacteria highlight the challenges of using FIB as model organisms for actual pathogens in natural sunlit environments.
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human health risk implications of multiple sources of faecal Indicator Bacteria in a recreational waterbody
Water Research, 2014Co-Authors: Jeffrey A Soller, Alexandria B Boehm, Mary E Schoen, Arun Varghese, Audrey Ichida, Sorina E Eftim, Nicholas J Ashbolt, John RavenscroftAbstract:Abstract We simulate the influence of multiple sources of enterococci (ENT) as faecal Indicator Bacteria (FIB) in recreational water bodies on potential human health risk by considering waters impacted by human and animal sources, human and non-pathogenic sources, and animal and non-pathogenic sources. We illustrate that risks vary with the proportion of culturable ENT in water bodies derived from these sources and estimate corresponding ENT densities that yield the same level of health protection that the recreational water quality criteria in the United States seeks (benchmark risk). The benchmark risk is based on epidemiological studies conducted in water bodies predominantly impacted by human faecal sources. The key result is that the risks from mixed sources are driven predominantly by the proportion of the contamination source with the greatest ability to cause human infection (potency), not necessarily the greatest source(s) of FIB. Predicted risks from exposures to mixtures comprised of approximately 30% ENT from human sources were up to 50% lower than the risks expected from purely human sources when contamination is recent and ENT levels are at the current water quality criteria levels (35 CFU 100 mL -1 ). For human/non-pathogenic, human/gull, human/pig, and human/chicken faecal mixtures with relatively low human contribution, the predicted culturable enterococci densities that correspond to the benchmark risk are substantially greater than the current water quality criteria values. These findings are important because they highlight the potential applicability of site specific water quality criteria for waters that are predominantly un-impacted by human sources.
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engineering solutions to improve the removal of fecal Indicator Bacteria by bioinfiltration systems during intermittent flow of stormwater
Environmental Science & Technology, 2013Co-Authors: Sanjay K Mohanty, Andrew A. Torkelson, Kara L Nelson, Hanna Dodd, Alexandria B BoehmAbstract:Bioinfiltration systems facilitate the infiltration of urban stormwater into soil and reduce high flow events and flooding. Stormwater carries a myriad of pollutants including fecal Indicator Bacteria (FIB). Significant knowledge gaps exist about the ability of bioinfiltration systems to remove and retain FIB. The present study investigates the ability of model, simplified bioinfiltration systems containing quartz sand and iron oxide-coated quartz sand (IOCS) to remove two FIB (Enterococcus faecalis and Escherichia coli) suspended in synthetic stormwater with and without natural organic matter (NOM) as well as the potential for accumulated FIB to be remobilized during intermittent flow. The experiments were conducted in two phases: (1) the saturated columns packed with either sand or IOCS were contaminated by injecting stormwater with Bacteria followed by injection of sterile stormwater and (2) the contaminated columns were subjected to intermittent infiltration of sterile stormwater preceded by a pause d...
Richard L Whitman - One of the best experts on this subject based on the ideXlab platform.
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Conclusions and future use of fecal Indicator Bacteria for monitoring water quality and protecting human health
The Fecal Bacteria, 2014Co-Authors: Michael J. Sadowsky, Richard L WhitmanAbstract:This chapter focuses on the future use of fecal Indicator Bacteria for monitoring water quality and protecting human health. The mammalian gastrointestinal (GI) tract is dominated by microorganisms from the following phyla Firmicutes, Bacteroidetes, ProteoBacteria, ActinoBacteria, Verrumicrobia, and FusoBacteria, in a host-specific manner. The fecal Indicator Bacteria in the water column physically adsorb and desorb from particles and eventually make their way into soils, sediments, and sand. The negative impact of these pathogens on human health is likely to worsen in the future as many Bacteria have been shown to have resistance to multiple antibiotics. Future applications of array-based technology to water quality monitoring will likely become more routine in the future and may soon obviate the use of fecal Indicator Bacteria as surrogates for pathogens. Deterministic modeling of fecal Indicator Bacteria in surface waters also needs more research, particularly on pathogen-particle interactions, Bacterial inactivation and regrowth, and model validation. More research is also needed to better understand Bacterial flux and patterns for modeling water quality at beaches and waterways impacted by nonpoint sources of Bacteria. As the access to clean water is fundamental around the world, it is important to have suitable techniques for rapid and accurate detection and quantification of fecal Indicator Bacteria to protect water quality for drinking, recreational use, and food production.
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faecal Indicator Bacteria enumeration in beach sand a comparison study of extraction methods in medium to coarse sands
Journal of Applied Microbiology, 2009Co-Authors: Alexandria B Boehm, John F Griffith, Richard L Whitman, Thomas A Edge, Charles D Mcgee, Helena M Sologabriele, Yiping Cao, M A Getrich, Jenny Jay, Donna M FergusonAbstract:Aims: The absence of standardized methods for quantifying faecal Indicator Bacteria (FIB) in sand hinders comparison of results across studies. The purpose of the study was to compare methods for extraction of faecal Bacteria from sands and recommend a standardized extraction technique. Methods and Results: Twenty-two methods of extracting enterococci and Escherichia coli from sand were evaluated, including multiple permutations of hand shaking, mechanical shaking, blending, sonication, number of rinses, settling time, eluant-to-sand ratio, eluant composition, prefiltration and type of decantation. Tests were performed on sands from California, Florida and Lake Michigan. Most extraction parameters did not significantly affect Bacterial enumeration. anova revealed significant effects of eluant composition and blending; with both sodium metaphosphate buffer and blending producing reduced counts. Conclusions: The simplest extraction method that produced the highest FIB recoveries consisted of 2 min of hand shaking in phosphate-buffered saline or deionized water, a 30-s settling time, one-rinse step and a 10 : 1 eluant volume to sand weight ratio. This result was consistent across the sand compositions tested in this study but could vary for other sand types. Significance and Impact of the Study: Method standardization will improve the understanding of how sands affect surface water quality.
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abundance and characteristics of the recreational water quality Indicator Bacteria escherichia coli and enterococci in gull faeces
Journal of Applied Microbiology, 2003Co-Authors: Lisa R Fogarty, Sheridan K Haack, M J Wolcott, Richard L WhitmanAbstract:L. R. F O G A R T Y , S. K. H A A C K , M. J. W O L C O T T A N D R. L. W H I T M A N. 2003. Aims: To evaluate the numbers and selected phenotypic and genotypic characteristics of the faecal Indicator Bacteria Escherichia coli and enterococci in gull faeces at representative Great Lakes swimming beaches in the United States. Methods and Results: E. coli and enterococci were enumerated in gull faeces by membrane filtration. E. coli genotypes (rep-PCR genomic profiles) and E. coli (VitekGNI+) and enterococci (APIrapid ID 32 Strep and resistance to streptomycin, gentamicin, vancomycin, tetracycline and ampicillin) phenotypes were determined for isolates obtained from gull faeces both early and late in the swimming season. Identical E. coli genotypes were obtained only from single gull faecal samples but most faecal samples yielded more than one genotype (median of eight genotypes for samples with 10 isolates). E. coli isolates from the same site that clustered at ‡85% similarity were from the same sampling date and shared phenotypic characteristics, and at this similarity level there was population overlap between the two geographically isolated beach sites. Enterococcus APIprofiles varied with sampling date. Gull enterococci displayed wide variation in antibiotic resistance patterns, and high-level resistance to some antibiotics. Conclusions: Gull faeces could be a major contributor of E. coli (10 5 -10 9 CFU g )1 ) and enterococci (10 4 - 10 8 CFU g )1 ) to Great Lakes recreational waters. E. coli and enterococci in gull faeces are highly variable with respect to their genotypic and phenotypic characteristics and may exhibit temporal or geographic trends in these features. Significance and Impact of the Study: The high degree of variation in genotypic or phenotypic characteristics of E. coli or enterococci populations within gull hosts will require extensive sampling for adequate characterization, and will influence methods that use these characteristics to determine faecal contamination sources for recreational waters.
Maria Viklander - One of the best experts on this subject based on the ideXlab platform.
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Indicator Bacteria and associated water quality constituents in stormwater and snowmelt from four urban catchments
Journal of Hydrology, 2016Co-Authors: Helen Galfi, Jiri Marsalek, Helene Osterlund, Maria ViklanderAbstract:Summary Four Indicator Bacteria were measured in association with physico-chemical constituents and selected inorganics during rainfall, baseflow and snowmelt periods in storm sewers of four urban catchments in a northern Swedish city. The variation patterns of coliforms, Escherichia coli , enterococci and Clostridium perfringens concentrations were assessed in manually collected grab samples together with those of phosphorus, nitrogen, solids, and readings of pH, turbidity, water conductivity, temperature and flow rates to examine whether these constituents could serve as potential Indicators of Bacteria sources. A similar analysis was applied to variation patterns of eight selected inorganics typical for baseflow and stormwater runoff to test the feasibility of using these inorganics to distinguish between natural and anthropogenic sources of inflow into storm sewers. The monitored catchments varied in size, the degree of development, and land use. Catchment and season (i.e., rainy or snowmelt periods) specific variations were investigated for sets of individual stormwater samples by the principal component analysis (PCA) to identify the constituents with variation patterns similar to those of Indicator Bacteria, and to exclude the constituents with less similarity. In the reduced data set, the similarities were quantified by the clustering correlation analysis. Finally, the positive/negative relationships found between Indicator Bacteria and the identified associated constituent groups were described by multilinear regressions. In the order of decreasing concentrations, coliforms, E. coli and enterococci were found in the highest mean concentrations during both rainfall and snowmelt generated runoff. Compared to dry weather baseflow, concentrations of these three Indicators in stormwater were 10 (snowmelt runoff) to 10 2 (rain runoff) times higher. C. perfringens mean concentrations were practically constant regardless of the season and catchment. The type and number of variables associated with Bacteria depended on the degree of catchment development and the inherent complexity of Bacteria sources. The list of variables associated with Bacteria included the flow rate, solids with associated inorganics (Fe and Al) and phosphorus, indicating similar sources of constituents regardless of the season. On the other hand, Bacteria were associated with water temperature only during rain periods, and somewhat important associations of Bacteria with nitrogen and pH were found during the periods of snowmelt. Most of the associated constituents were positively correlated with Bacteria responses, but conductivity, with two associated inorganics (Si and Sr), was mostly negatively correlated in all the catchments. Although the study findings do not indicate any distinct surrogates to Indicator Bacteria, the inclusion of the above identified constituents (flow rate, solids and total phosphorus for all seasons, water temperature for rainfall runoff, and total nitrogen and pH for snowmelt only) in sanitary surveys of northern climate urban catchments would provide additional insight into Indicator Bacteria sources and their modeling.
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comparison of Indicator Bacteria concentrations obtained by automated and manual sampling of urban storm water runoff
Water Air and Soil Pollution, 2014Co-Authors: Helen Galfi, Kerstin Nordqvist, Monica Sundelin, Godecketobias Blecken, Jiri Marsalek, Maria ViklanderAbstract:A comparative study of Indicator Bacteria concentrations obtained by laboratory analysis of grab samples of storm water, which were collected manually or by automatic samplers, was carried out in two urban catchments. Samples were analyzed for four types of Indicator Bacteria, total coliforms, Escherichia coli (E. coli), enterococci, and Clostridium perfringens and further documented by measurements of total suspended solids (TSS) and turbidity. Analysis of complete data sets (N = 198) indicated no statistically significant differences in the geometric means of all the constituent samples collected automatically or manually, but there were some small differences between the results produced by the two sampling methods applied. Total coliform concentrations were positively biased in samples collected by automatic samplers, but for the three remaining Indicator Bacteria (E. coli, enterococci, and C. perfringens), the opposite was true. Risk of sample cross-contamination in automatic samplers was assessed in the laboratory by sampling consecutively synthetic storm water with high and low concentrations of E. coli and enterococci. The first low-concentration samples preceded by high-concentration samples were cross-contaminated and the measured concentrations were positively biased. This cross-contamination was explained by storm-water residue in the sampling line. Such a residue remained in place even after line purging by compressed air, and its mass depended on the sampling line length (tested up to 5 m), as verified by measurements in the laboratory. The study findings should be helpful for improving field protocols for Indicator Bacteria sampling.
Valerie J Harwood - One of the best experts on this subject based on the ideXlab platform.
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determination of wild animal sources of fecal Indicator Bacteria by microbial source tracking mst influences regulatory decisions
Water Research, 2018Co-Authors: Karena H Nguyen, C Senay, Suzanne Young, Bina Nayak, Aldo Lobos, James W Conrad, Valerie J HarwoodAbstract:Fecal Indicator Bacteria (FIB) are used to assess fecal pollution levels in surface water and are among the criteria used by regulatory agencies to determine water body impairment status. While FIB provide no information about pollution source, microbial source tracking (MST) does, which contributes to more direct and cost effective remediation efforts. We studied a watershed in Florida managed for wildlife conservation that historically exceeded the state regulatory guideline for fecal coliforms. We measured fecal coliforms, enterococci, a marker gene for avian feces (GFD), and a marker gene for human-associated Bacteroides (HF183) in sediment, vegetation, and water samples collected monthly from six sites over two years to: 1) assess the influence of site, temporal factors, and habitat (sediment, vegetation, and water) on FIB and MST marker concentrations, 2) test for correlations among FIB and MST markers, and 3) determine if avian feces and/or human sewage contributed to FIB levels. Sediment and vegetation had significantly higher concentrations of FIB and GFD compared to water and thus may serve as microbial reservoirs, providing unreliable indications of recent contamination. HF183 concentrations were greatest in water samples but were generally near the assay limit of detection. HF183-positive results were attributed to white-tailed deer (Odocoileus virginianus) feces, which provided a false indication of human sewage in this water body. FIB and GFD were positively correlated while FIB and HF183 were negatively correlated. We demonstrated that birds, not sewage, were the main source of FIB, thus avoiding implementation of a total maximum daily load program (TMDL). Our results demonstrate that the concomitant use of FIB and MST can improve decision-making and provide direction when water bodies are impaired, and provides a strategy for natural source exclusion in water bodies impacted by wild animal feces.
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association of fecal Indicator Bacteria with human viruses and microbial source tracking markers at coastal beaches impacted by nonpoint source pollution
Applied and Environmental Microbiology, 2012Co-Authors: Shannon Mcquaig, John F Griffith, Valerie J HarwoodAbstract:Water quality was assessed at two marine beaches in California by measuring the concentrations of culturable fecal Indicator Bacteria (FIB) and by library-independent microbial source tracking (MST) methods targeting markers of human-associated microbes (human polyomavirus [HPyV] PCR and quantitative PCR, Methanobrevibacter smithii PCR, and Bacteroides sp. strain HF183 PCR) and a human pathogen (adenovirus by nested PCR). FIB levels periodically exceeded regulatory thresholds at Doheny and Avalon Beaches for enterococci (28.5% and 31.7% of samples, respectively) and fecal coliforms (20% and 5.8%, respectively). Adenoviruses were detected at four of five sites at Doheny Beach and were correlated with detection of HPyVs and human Bacteroides HF183; however, adenoviruses were not detected at Avalon Beach. The most frequently detected human source marker at both beaches was Bacteroides HF183, which was detected in 27% of samples. Correlations between FIBs and human markers were much more frequent at Doheny Beach than at Avalon Beach; e.g., adenovirus was correlated with HPyVs and HF183. Human sewage markers and adenoviruses were routinely detected in samples meeting FIB regulatory standards. The toolbox approach of FIB measurement coupled with analysis of several MST markers targeting human pathogens used here demonstrated that human sewage is at least partly responsible for the degradation of water quality, particularly at Doheny Beach, and resulted in a more definitive assessment of recreational water quality and human health risk than reliance on FIB concentrations alone could have provided.
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test of direct and indirect effects of agrochemicals on the survival of fecal Indicator Bacteria
Applied and Environmental Microbiology, 2011Co-Authors: Zachery R Staley, Jason R Rohr, Valerie J HarwoodAbstract:Water bodies often receive agrochemicals and animal waste carrying fecal Indicator Bacteria (FIB) and zoonotic pathogens, but we know little about the effects of agrochemicals on these microbes. We assessed the direct effects of the pesticides atrazine, malathion, and chlorothalonil and inorganic fertilizer on Escherichia coli and enterococcal survival in simplified microcosms held in the dark. E. coli strain composition in sediments and water column were positively correlated, but none of the agrochemicals had significant direct effects on E. coli strain composition or on densities of culturable FIBs. In a companion study, microcosms with nondisinfected pond water and sediments were exposed to or shielded from sunlight to examine the potential indirect effects of atrazine and inorganic fertilizer on E. coli. The herbicide atrazine had no effect on E. coli in dark-exposed microcosms containing natural microbial and algal communities. However, in light-exposed microcosms, atrazine significantly lowered E. coli densities in the water column and significantly increased densities in the sediment compared to controls. This effect appears to be mediated by the effects of atrazine on algae, given that atrazine significantly reduced phytoplankton, which was a positive and negative predictor of E. coli densities in the water column and sediment, respectively. These data suggest that atrazine does not directly affect the survival of FIB, rather that it indirectly alters the distribution and abundance of E. coli by altering phytoplankton and periphyton communities. These results improve our understanding of the influence of agricultural practices on FIB densities in water bodies impacted by agricultural runoff.
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quantifying environmental reservoirs of fecal Indicator Bacteria associated with sediment and submerged aquatic vegetation
Environmental Microbiology, 2011Co-Authors: Brian D Badgley, Florence I M Thomas, Valerie J HarwoodAbstract:Elevated concentrations of fecal Indicator Bacteria (FIB) in aquatic sediments and vegetation have prompted concern that environmental reservoirs of FIB disrupt the correlation between Indicator organisms, pathogens and human health risks. FIB numbers, however, are typically normalized to volume of water or mass of substrate. Because these reservoirs tend to differ greatly in magnitude within and between water bodies, direct comparison between water column and benthic population sizes can be problematic. Normalization to a set volume of water or mass of substrate, e.g. cfu (100 ml)(-1) or cfu(100 g)(-1), can give a false picture of the relative contributions of various reservoirs to FIB numbers across the ecosystem, and of the potential for FIBs to trigger health advisories as they pass from one reservoir to another. Here, we normalized enterococci concentrations from water, sediment and submerged aquatic vegetation (SAV) to land surface area (m(2) ) to compare their relative importance in the entire system. SAV-associated enterococci comprised only 0-18% of the entire population, even though they displayed the highest concentrations of enterococci per unit mass. The largest proportion of the enterococci population was in the water column (4-77%) or sediments (20-95%), depending on the volume of each substrate available at a site and FIB concentrations within them. Models indicated that large shifts in the relative size of FIB populations in each substrate can result from changes in per cent SAV cover, water depth and depth of sediment colonization. It follows that high concentrations of FIB in sediments or SAV do not necessarily signify large environmental reservoirs of FIB that can affect the water column. Comprehensive analyses that include FIB measurements from water, SAV and sediment normalized to land surface area offer a more balanced perspective on total FIB numbers contained in various matrices of an aquatic system.
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classification of antibiotic resistance patterns of Indicator Bacteria by discriminant analysis use in predicting the source of fecal contamination in subtropical waters
Applied and Environmental Microbiology, 2000Co-Authors: Valerie J Harwood, John E Whitlock, Victoria WithingtonAbstract:The antibiotic resistance patterns of fecal streptococci and fecal coliforms isolated from domestic wastewater and animal feces were determined using a battery of antibiotics (amoxicillin, ampicillin, cephalothin, chlortetracycline, oxytetracycline, tetracycline, erythromycin, streptomycin, and vancomycin) at four concentrations each. The sources of animal feces included wild birds, cattle, chickens, dogs, pigs, and raccoons. Antibiotic resistance patterns of fecal streptococci and fecal coliforms from known sources were grouped into two separate databases, and discriminant analysis of these patterns was used to establish the relationship between the antibiotic resistance patterns and the Bacterial source. The fecal streptococcus and fecal coliform databases classified isolates from known sources with similar accuracies. The average rate of correct classification for the fecal streptococcus database was 62.3%, and that for the fecal coliform database was 63.9%. The sources of fecal streptococci and fecal coliforms isolated from surface waters were identified by discriminant analysis of their antibiotic resistance patterns. Both databases identified the source of Indicator Bacteria isolated from surface waters directly impacted by septic tank discharges as human. At sample sites selected for relatively low anthropogenic impact, the dominant sources of Indicator Bacteria were identified as various animals. The antibiotic resistance analysis technique promises to be a useful tool in assessing sources of fecal contamination in subtropical waters, such as those in Florida.
John Poté - One of the best experts on this subject based on the ideXlab platform.
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characterization of fecal Indicator Bacteria in sediments cores from the largest freshwater lake of western europe lake geneva switzerland
Ecotoxicology and Environmental Safety, 2012Co-Authors: Florian Thevenon, Walter Wildi, Nicole Regier, Cinzia Benagli, Mauro Tonolla, Thierry Adatte, John PotéAbstract:This study characterized the fecal Indicator Bacteria (FIB), including Escherichia coli (E. coli) and Enteroccocus (ENT), disseminated over time in the Bay of Vidy, which is the most contaminated area of Lake Geneva. Sediments were collected from a site located at ∼500 m from the present waste water treatment plant (WWTP) outlet pipe, in front of the former WWTP outlet pipe, which was located at only 300 m from the coastal recreational area (before 2001). E. coli and ENT were enumerated in sediment suspension using the membrane filter method. The FIB characterization was performed for human Enterococcus faecalis (E. faecalis) and Enterococcus faecium (E. faecium) and human specific bacteroides by PCR using specific primers and a matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Bacterial cultures revealed that maximum values of 35.2×108 and 6.6×106 CFU g−1 dry sediment for E. coli and ENT, respectively, were found in the sediments deposited following eutrophication of Lake Geneva in the 1970s, whereas the WWTP started operating in 1964. The same tendency was observed for the presence of human fecal pollution: the percentage of PCR amplification with primers ESP-1/ESP-2 for E. faecalis and E. faecium indicated that more than 90% of these Bacteria were from human origin. Interestingly, the PCR assays for specific-human bacteroides HF183/HF134 were positive for DNA extracted from all isolated strains of sediment surrounding WWPT outlet pipe discharge. The MALDI-TOF MS confirmed the presence of general E. coli and predominance E. faecium in isolated strains. Our results demonstrated that human fecal Bacteria highly increased in the sediments contaminated with WWTP effluent following the eutrophication of Lake Geneva. Additionally, other FIB cultivable strains from animals or adapted environmental strains were detected in the sediment of the bay. The approaches used in this research are valuable to assess the temporal distribution and the source of the human fecal pollution in aquatic environments.
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distribution and survival of faecal Indicator Bacteria in the sediments of the bay of vidy lake geneva switzerland
Ecological Indicators, 2009Co-Authors: Laurence Haller, John Poté, Jeanluc Loizeau, Walter WildiAbstract:Abstract The purpose of this study was to determine the concentrations and the horizontal distribution of faecal Indicator Bacteria (FIB) including Escherichia coli and Enterococcus sp. in the bottom sediments of the Bay of Vidy, City of Lausanne, Switzerland. A vertical distribution of FIB in sediments near the municipal wastewater treatment plant (WWTP) outlet was evaluated and their persistence in those sediments was monitored for a period of 90 days. High FIB levels were measured in the sediments sampled near the WWTP outlet pipe and the mouth of the Chamberonne River, at concentrations ranging between 105 and 107 CFU 100 g−1. FIB levels at 10 cm depth in the sediments near the WWTP outlet pipe ranged between 104 and 105 CFU 100 g−1, and were still detected in the top 6 cm after 90 days. Results of this study indicate that freshwater sediments of the Bay of Vidy constitute a reservoir of faecal Indicator Bacteria, which can persist in certain areas of the bay. Possible resuspension of FIB and pathogens may affect water quality and may increase health risks to sensitive populations during recreational activities. FIB survival in sediments for long periods is of considerable significance for the understanding of microbial pollution in water and for the management of risk at specific recreational coastal sites.
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Influence of Freshwater Sediment Characteristics on Persistence of Fecal Indicator Bacteria
Water Air and Soil Pollution, 2009Co-Authors: Laurence Haller, Essoêfli Amedegnato, John Poté, Walter WildiAbstract:Extended persistence of enteric Bacteria in coastal sediments and potential remobilization of pathogens during natural turbulence or human activities may induce an increased risk of human infections. In this study, the effect of sediment characteristics such as particle grain size and nutrient and organic matter contents on the survival of fecal Indicator Bacteria (FIB) including total coliforms, Escherichia coli, and Enterococcus was investigated. The experimentation was carried out for 50 days in microcosms containing lake water and different contaminated freshwater sediments in continuous-flow and batch conditions. Results of this study revealed: (1) extended FIB survival in sediments up to 50 days, (2) higher growth and lower decay rates of FIB in sediments with high levels of organic matter and nutrients and small (mainly silt) grain size, and (3) longer survival of Enterococcus sp. compared to E. coli and total coliforms. FIB survival in sediments and possible resuspension are of considerable significance for the understanding of permanent microbial pollution in water column and therefore human risk during recreational activities
