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In this study, physicochemical parameters such as total dissolved solids (TDS), pH, temperature, and electrical conductivity (EC) and antibiotic resistance profiles of Escherichia coli isolated from surface waters of 5 different stations of the Atatürk Dam in Adıyaman were investigated. It was found that the water was of good quality in terms of total dissolved solids and electrical conductivity. It shows alkaline properties in regard to pH values. In terms of temperature values, it is of fourth-class quality. Seventy E. coli strains were isolated as an indicator of fecal contamination. In isolated E. coli, antibiotic resistance was determined as 95% for erythromycin, 31.42% for ceftaroline, 30% for cefazolin, 14.28% for tertacycline, 8.50% for chloramphenicol, 4.28% for cefuroxine, and 2.85% for both safotaxime and cefepime. Multiple antibiotic resistance (MAR) rates of 85.71% of bacteria isolated from Sitilce station and 50% of bacteria isolated from Eğri stream station were found to be greater than 0.2. MAR indexes of all bacteria isolated from Kahta, Gerger, and Samsat stations were found to be lower than or equal to 0.2. The results indicated that surface waters of Eğri stream and Sitilce regions may be discharge points of domestic and industrial wastewaters. [ABSTRACT FROM AUTHOR]

Abstract Coliphage have been proposed as indicators of fecal contamination in recreational waters because they better reflect the persistence of pathogenic viruses in the environment and through wastewater treatment than traditional fecal indicator bacteria. Herein, we conducted a systematic literature search of peer-reviewed publications to identify coliphage density data (somatic and male-specific, or MSC) in raw wastewater and ambient waters. The literature review inclusion criteria included scope, study quality, and data availability. A non-parametric two-stage bootstrap analysis was used to estimate the coliphage distributions in raw wastewater and account for geographic region and season. Additionally, two statistical methodologies were explored for developing coliphage density distributions in ambient waters, to account for the nondetects in the datasets. In raw wastewater, the analysis resulted in seasonal density distributions of somatic coliphage (SC) (mean 6.5 log 10 plaque forming units (PFU)/L; 95% confidence interval (CI): 6.2–6.8) and MSC (mean 5.9 log 10 PFU/L; 95% CI: 5.5–6.1). In ambient waters, 49% of MSC samples were nondetects, compared with less than 5% for SC. Overall distributional estimates of ambient densities of coliphage were statistically higher for SC than for MSC (mean 3.4 and 1.0 log 10 PFU/L, respectively). Distributions of coliphage in raw wastewater and ambient water will be useful for future microbial risk assessments. Highlights • Systematic review conducted of coliphage levels in raw wastewater and ambient waters. • Studies conducted in 19 countries provided 2124 individual coliphage data points. • Somatic coliphage outnumber MSC densities in raw wastewater and in ambient waters. • Overall coliphage densities were significantly higher in colder seasons. • Coliphage distributions will inform quantitative microbial risk assessment efforts. [ABSTRACT FROM AUTHOR]

The current water quality monitoring and regulation approaches use fecal indicator bacteria (FIB) to indirectly assess health risks from fecal pathogens. Direct detection of waterborne pathogens is expected to provide more accurate and comprehensive risk assessment, which however has been hindered by the lack of methods for simultaneous detection of the numerous waterborne pathogens. This study aimed to develop a mPCR-NGS approach that uses the high sequencing depth of NGS and sequence-based detection to significantly increase the multiplex level of mPCR for direct pathogen detection in water. Individual PCR primers were designed for 16 target marker genes of nine different bacterial pathogens, and an optimal combination of primers with least primer complementarities was identified for the multiplex setting. Using an artificial tester sample, the mPCR system was optimized for annealing temperature and primer concentration, and bioinformatic procedures were developed to directly detect the target marker gene amplicons in NGS sequence reads, which showed simultaneous detection of 14 different target genes in one reaction. The effectiveness of the developed mPCR-NGS approach was subsequently demonstrated on DNA extracts from stream water samples and their counterparts that were spiked with various target pathogen DNA, and all target genes spiked into the environmental water samples were successfully detected. Several key issues for further improving the mPCR-NGS approach were also identified and discussed. [ABSTRACT FROM AUTHOR]

The genetic characteristics among Escherichia coli strains can be grouped by origin of isolation. Then, it is possible to use the genotypes as a tool to determine the source of water contamination. The aim of this study was to define water aptitude for human consumption in a rural basin and to assess the diversity of E. coli water populations. Thus, it was possible to identify the main sources of fecal contamination and to explore linkages with the hydrogeological environment and land uses. The bacteriological analysis showed that more than 50% of samples were unfit for human consumption. DNA fingerprinting analysis by BOX-PCR indicated low genotypic diversity of E. coli isolates taken from surface water and groundwater. The results suggested the presence of a dominant source of fecal contamination. The relationship between low genotypic diversity and land use would prove that water contamination comes from livestock. The genetic diversity of E. coli isolated from surface water was less than that identified in groundwater because of the different hydraulic features of both environments. Furthermore, each one of the two big strain groups identified in this basin is located in different sub-basins, showing that hydrological dynamics exerts selective pressure on bacteria DNA. [ABSTRACT FROM AUTHOR]

It is important that indicators of fecal pollution are reliable. Coliform bacteria are a commonly used indicator of fecal pollution. As other investigators have reported elsewhere, we observed a seasonal pattern of coliform bacteria detections in domestic wells in New Jersey. Examination of a statewide database of 10 years of water quality data from 93,447 samples, from 78,207 wells, generated during real estate transactions, revealed that coliform bacteria were detected in a higher proportion of wells during warm weather months. Further examination of the seasonal pattern of other data, including well water pH, precipitation, ground and surface water temperatures, surface water coliform bacteria concentrations, and vegetation, resulted in the hypothesis that these bacteria may be derived from nonfecal (or environmentally adapted) as well as fecal sources. We provide evidence that the coliform seasonality may be the result of seasonal changes in groundwater extraction volumes (and to a lesser extent precipitation), and temperature-driven changes in the concentration of surface or near-surface coliform sources. Nonfecal coliform sources may not indicate the presence of fecal wastes and hence the potential presence of pathogens, or do so in an inconsistent fashion. Additional research is needed to identify the sources of the coliforms detected in groundwater. [ABSTRACT FROM AUTHOR]

Routine water quality monitoring practices based on the enumeration of culturable Escherichia coli provides no information about the source or age of fecal pollution. An emerging strategy is to use culturable E. coli and the DNA markers of Bacteroidales complementarily for microbial source tracking. In this study, we consistently observed in seawater microcosms of 3 different conditions that culturable E. coli decayed faster ( T99 = 1.14 - 4.29 days) than Bacteroidales DNA markers did ( T99 = 1.81 - 200.23 days). Concomitantly, the relative concentration between Bacteroidales DNA markers and culturable E. coli increased over time in all treatments. Particularly, the increase during the early stage of the experiments (before T99 of E. coli was reached) was faster than during the later stage (after T99 of E. coli was attained). We propose that the tracking of the relative concentration between Bacteroidales DNA markers and culturable E. coli provides an opportunity to differentiate a pollution that is relatively fresh from one that has aged. This method, upon further investigation and validation, could be useful in episodic pollution events where the surge of E. coli concentration causes noncompliance to the single sample maximum criterion that mandates high frequency follow-up monitoring. [ABSTRACT FROM AUTHOR]

Coupled measurements of nitrate (NO 3 − ), nitrogen (N), and oxygen (O) isotopic composition (δ 15 N NO3 and δ 18 O NO3 ) were used to investigate the sources and processes of N cycling, while the microbial source tracking (MST) method was used to identify microbiological pollution in the surface water of the Sava River Basin (SRB) in autumn in 2014 and 2015 during high and low water discharge. Atmospheric nitrate deposition or nitrate-containing fertilizers were found not to be significant sources of riverine nitrate in the SRB. The ranges of isotope values suggest that NO 3 − in the SRB derives from soil nitrification, sewage, and/or manure, which were further supported by MST analysis. Microbiological indicators show the existence of hotspots of fecal pollution in the SRB, which are human associated. Long-term observations indicate persistent fecal contamination at selected locations caused by continuous discharge of untreated wastewaters into the SRB. [ABSTRACT FROM AUTHOR]

A rational-based physical descriptive model (PDM) has been developed to predict the levels of Escherichia coli in water at a beach with dynamic conditions in the Greater Toronto Area (GTA), Ontario, Canada. Bacteria loadings in the water were affected not only by multiple physical factors (precipitation, discharge, wind, etc.), but also by cumulative effects, intensity, duration and timing of storm events. These may not be linearly related to the observed variations in bacteria levels, and are unlikely to be properly represented by a widely used multiple linear regression model. In order to account for these complex relationships, the amounts of precipitation and nearby creek discharge, the impact of various time-related factors, lag time between events and sample collection, and threshold for different parameters were used in determining bacteria levels. This new comprehensive PDM approach improved the accuracy of the E. coli level predictions in the studied beach water compared to the previously developed statistical predictive and presently used geometric mean models. In spite of the complexity and dynamic conditions at the studied beach, the PDM achieved 75% accuracy overall for the five case years examined. [ABSTRACT FROM AUTHOR]

Fecal contamination of drinking water is a major health problem which accounts for many cases of diarrhea mainly in infants and foreigners. This contamination is a complex interaction of many parameters. Antibiotic resistance among bacterial isolates complicates the problem. The study was done to identify fecal contamination of drinking water by Diarrheagenic Antibiotic-Resistant Escherichia coli in Zagazig city and to trace reasons for such contamination, three hundred potable water samples were investigated for E. coli existence. Locations of E. coli positive samples were investigated in relation to population density, water source, and type of water pipe. Sixteen E. coli strains were isolated. Antibiotic sensitivity was done and enterotoxigenic, enteropathogenic, and enterohaemorrhagic virulence genes were investigated by PCR. Probability of fecal contamination correlated with higher population density, with increased distance from Zagazig water plant, and with asbestos cement water pipes. Resistance to at least one antimicrobial drug was found in all isolates. Virulence genes were detected in a rate of 26.27%, 13.13%, 20%, 6.67%, and 33.33% for LT, ST, stx1, stx2, and eae genes, respectively. This relatively high frequency of fecal contamination points towards the high risk of developing diarrhea by antibiotic resistant DEC in low socioeconomic communities particularly with old fashion distribution systems. [ABSTRACT FROM AUTHOR]

The role of environmental forcings on the fecal contamination dynamics in small coastal streams was investigated, using the Aljezur coastal stream (Portugal) as a test case. An integrated modeling approach, combining hydrological and coupled hydrodynamic-fecal indicator bacteria models, was applied to selected scenarios of relevant forcings, on the basis of previously calibrated and validated model applications. The forcings investigated included: tides, winds, waves, atmospheric pressure, bathymetry, river flow, and upstream fecal bacteria concentrations; this study targeted the characterization of the relative importance of these factors on the fecal contamination dynamics, to enhance our understanding of small coastal streams water quality dynamics. Results highlight distinct patterns for dry and wet periods. Fecal bacteria transport is mainly forced by tidal propagation, in dry periods; and by freshwater flows, during wet periods. The analysis reveals a complex hydraulic and water quality dynamic resulting from the interactions between the environmental forcings and strongly dependent on their relative strength. This analysis can be extrapolated for systems with a similar balance between the environmental factors. [ABSTRACT FROM AUTHOR]

Background: Packaged water products provide an increasingly important source of water for consumption. However, recent studies raise concerns over their safety. Objectives: To assess the microbial safety of packaged water, examine differences between regions, country incomes, packaged water types, and compare packaged water with other water sources. Methods: We performed a systematic review and meta-analysis. Articles published in English, French, Portuguese, Spanish and Turkish, with no date restrictions were identified from online databases and two previous reviews. Studies published before April 2014 that assessed packaged water for the presence of Escherichia coli, thermotolerant or total coliforms were included provided they tested at least ten samples or brands. Results: A total of 170 studies were included in the review. The majority of studies did not detect fecal indicator bacteria in packaged water (78/141). Compared to packaged water from upper-middle and high-income countries, packaged water from low and lower-middle-income countries was 4.6 (95% CI: 2.6–8.1) and 13.6 (95% CI: 6.9–26.7) times more likely to contain fecal indicator bacteria and total coliforms, respectively. Compared to all other packaged water types, water from small bottles was less likely to be contaminated with fecal indicator bacteria (OR = 0.32, 95%CI: 0.17–0.58) and total coliforms (OR = 0.10, 95%CI: 0.05, 0.22). Packaged water was less likely to contain fecal indicator bacteria (OR = 0.35, 95%CI: 0.20, 0.62) compared to other water sources used for consumption. Conclusions: Policymakers and regulators should recognize the potential benefits of packaged water in providing safer water for consumption at and away from home, especially for those who are otherwise unlikely to gain access to a reliable, safe water supply in the near future. To improve the quality of packaged water products they should be integrated into regulatory and monitoring frameworks. [ABSTRACT FROM AUTHOR]

We investigated fecal indicator bacteria (FIB) concentrations in water and sediment from Carpinteria Salt Marsh, a medium-sized (93 ha), mostly natural southern California coastal wetland. High FIB concentrations, exceeding recreational water quality standards, were found at inlet sites after winter storm events and during a summer dry weather sampling event. Runoff entering the wetland had the highest concentrations of FIB after large rain events and after rain events following extended periods without rain. The watersheds with the greatest agricultural and urban development draining into the wetland generally contributed the highest loads of FIB, while the largest and least developed watershed contributed the lowest FIB concentrations. Surface water exiting the wetland at the ocean contained relatively low concentrations of FIB and only exceeded recreational water quality standards after the largest rain event of the year. Bacterial concentrations in sediment were only elevated after rain events, suggesting wetland sediment was not a reservoir for bacteria. Our results provide evidence that moderate-sized tidal wetlands at the base of moderately urbanized watersheds can attenuate FIB, improving coastal water quality. [ABSTRACT FROM AUTHOR]

Human faecal contamination poses a widespread hazard for human health. In urban areas, sewer leakage may be an important cause of faecal pollution to surface water. Faecal indicator bacteria (FIB) are the most widely used indicators to monitor surface water quality. However, assessing whether a water body is meeting water quality criteria is made difficult by the high variability of FIB concentrations over time. In this study, the variation of FIB concentration in surface water from tropical urban catchments is investigated. Eleven urban sub-catchments were sampled hourly over 24-hr and samples analysed for FIB. It was found that FIB show a diurnal pattern that is characterised by daytime FIB concentrations that are significantly higher than nighttime FIB concentrations. This observed diurnal variation of FIB closely follows that of sewer flows and contrasts with observations in rural streams where FIB concentrations are known to be low in the daytime and high during the night. Field tracer tests provide qualitative evidence of sewage exfiltration and transport to drains via preferential flow paths. The diurnal FIB variation and field tracer tests indicate the likelihood of surface water contamination due to leaking sewers. The results further suggest that contamination of surface-water drains is likely a widespread problem in tropical urban areas due to extensive drainage networks and the persistence of FIB under tropical conditions. Because of FIB variation over time, the time at which samples are collected is important in being able to capture the daily maximum and minimum FIB concentrations. The Kruskal–Wallis test shows that hourly sampling from 04:00 to 07:00 and from 12:00 to 15:00 results in significantly different FIB concentration (minimum and maximum, respectively). Furthermore, the Wilcoxon-Mann-Whitney test shows that sampling at 12:00 and 14:00 results in significantly higher FIB concentrations, while sampling at 05:00 and 04:00 or 05:00 and 06:00 results in significantly lower FIB concentrations, than sampling at other hours of the day. [ABSTRACT FROM AUTHOR]

Enclosed beaches along urban coastlines are frequent hot spots of fecal indicator bacteria (FIB) pollution. In this paper we present field measurements and modeling studies aimed at evaluating the impact of small storm drains on FIB pollution at enclosed beaches in Newport Bay, the second largest tidal embayment in Southern California. Our results suggest that small drains have a disproportionate impact on enclosed beach water quality for five reasons: ( l) dry weather surface flows (primarily from over irrigation of lawns and ornamental plants) harbor FIB at concentrations exceeding recreational water quality criteria; (2) small drains can trap dry weather runoff during high tide, and then release it in a bolus during the falling tide when drainpipe outlets are exposed; (3) near shore turbulence is low (turbulent diffusivities approximately 10-3 m2 s-1'), limiting dilution of FIB and other run off associated pollutants once they enter the bay; (4) once in the bay, runoff can form buoyant plumes that further limit vertical mixing and dilution; and (5) local winds can force buoyant runoff plumes back against the shoreline, where water depth is minimal and human contact likely. Outdoor water conservation and urban retrofits that minimize the volume of dry and wet weather runoff entering the local storm drain system may be the best option for improving beach water quality in Newport Bay and other urban-impacted enclosed beaches. [ABSTRACT FROM AUTHOR]

Aims: To evaluate the use of nonlocal, already-available strains of phages to indicate faecal contamination in Thailand waters. Methods and Results: Phages of Bacteroides fragilis strains ATCC 700786 (RYC2056PH) and ATCC 51477 (HSP40PH) were measured in 71 human and animal wastewater samples in Thailand using a double-layer agar assay. Bacteriophage RYC2056PH was detected at concentrations comparable to representative human and animal wastewater samples from European and Mediterranean countries, with 61·7 and 33·3% above the threshold value of 100 PFU 100 ml-1 in wastewater samples of human and animal origins, respectively. On the other hand, HSP40PH was detected at low concentrations in both human- and animal-polluted wastewaters. Moreover, RYC2056PH was found in 12 canal waters with human-influenced pollution and was not detected in 6 nonpolluted river waters being tested in this study. Conclusions: The presence of RYC2056PH could indicate nonsource-specific faecal contamination in Thailand. Significance and Impact of the Study: This study provided the first evidence that bacteriophages of the European-isolated B. fragilis strain RYC2056 could be used as nonsource-specific faecal indicators in the Southeast Asian region. The results of this study support the worldwide use of Bacteroides phages as faecal indicators. [ABSTRACT FROM AUTHOR]

: Robert Bain and colleagues conduct a systematic review and meta-analysis to assess whether water from “improved” sources is less likely to contain fecal contamination than “unimproved” sources and find that access to an “improved source” provides a measure of sanitary protection but does not ensure water is free of fecal contamination. Please see later in the article for the Editors' Summary [ABSTRACT FROM AUTHOR]

Enterococci are common members of the gut microbiome and their ease of culturing has facilitated worldwide use as indicators of fecal pollution of waters. However, enterococci were recently shown to persist in environmental habitats, often in the absence of fecal input, potentially confounding water quality assays. Toward resolving this issue and providing a more complete picture of natural enterococci diversity, 11 isolates of Enterococcus faecalis recovered from freshwater watersheds (environmental) were sequenced and compared to 59 available enteric genomes. Phenotypically and phylogenetically the environmental E. faecalis were indistinguishable from their enteric counterparts. However, distinct environmental- and enteric-associated gene signatures, encoding mostly accessory nutrient utilization pathways, were detected among the variable genes. Specifically, a nickel uptake operon was over-represented in environmental genomes, while genes for utilization of sugars thought to be abundant in the gut such as xylose were over-represented in enteric genomes. The distribution and phylogeny of these identified signatures suggest that ancestors of R faecalis resided in extra-enteric habitats, challenging the prevailing commensal view of enterococci ecology. Thus, habitat-associated gene content changes faster than core genome phylogeny and may include biomarkers for reliably detecting fecal contaminants for improved microbial water quality monitoring. [ABSTRACT FROM AUTHOR]

Some molecular methods for tracking fecal pollution in environmental waters have both PCR and quantitative PCR (qPCR) assays available for use. To assist managers in deciding whether to implement newer qPCR techniques in routine monitoring programs, we compared detection limits (LODs) and costs of PCR and qPCR assays with identical targets that are relevant to beach water quality assessment. For human-associated assays targeting Bacteroidales HF183 genetic marker, qPCR LODs were 70 times lower and there was no effect of target matrix (artificial freshwater, environmental creek water, and environmental marine water) on PCR or qPCR LODs. The PCR startup and annual costs were the lowest, while the per reaction cost was 62% lower than the Taqman based qPCR and 180% higher than the SYBR based qPCR. For gull-associated assays, there was no significant difference between PCR and qPCR LODs, target matrix did not effect PCR or qPCR LODs, and PCR startup, annual, and per reaction costs were lower. Upgrading to qPCR involves greater startup and annual costs, but this increase may be justified in the case of the human-associated assays with lower detection limits and reduced cost per sample. [Copyright &y& Elsevier]

Hepatitis A virus (HAV) strains found in selected South African (SA) surface waters were characterised to establish what HAV types are circulating in the environment, thus reflecting circulation in the surrounding communities. Surface water samples used for irrigation or domestic purposes, and water samples from the outflow of wastewater plants were collected from six provinces. Viruses were recovered from the samples using a glass wool adsorption-elution method and then further concentrated using polyethylene glycol/sodium chloride precipitation. After automated nucleic acid extraction, samples were analysed for HAV by real-time reverse-transcriptase polymerase chain reaction. HAV strains were genotyped by nucleotide sequence analysis of the capsid gene VP1 and the VP1/P2B junction. HAVs were detected in 76% (16/21) of the surface water samples and in 37% (19/51) of the samples from the wastewater plants. Strains were characterised from 32 of the 35 samples and classified within genotype IB. The presence of genotype IB in the water sources confirms human faecal contamination. Hence, these faecally-contaminated water sources may be a potential transmission route of HAV infection and a potential source of contamination of irrigated fresh produce in SA. [ABSTRACT FROM AUTHOR]

Gulls are prevalent in beach environments and can be a major source of fecal contamination. Gulls have been shown to harbor a high abundance of fecal indicator bacteria (FIB), such as Escherichia coli and enterococci, which can be readily detected as part of routine beach monitoring. Despite the ubiquitous presence of gull fecal material in beach environments, the associated microbial community is relatively poorly characterized. We generated comprehensive microbial community profiles of gull fecal samples using Roche 454 and Illumina MiSeq platforms to investigate the composition and variability of the gull fecal microbial community and to measure the proportion of FIB. Enterococcaceae and Enterobacteriaceae were the two most abundant families in our gull samples. Sequence comparisons between short-read data and nearly full-length 16S rRNA gene clones generated from the same samples revealed Catellicoccus marimammalium as the most numerous taxon among all samples. The identification of bacteria from gull fecal pellets cultured on membrane-Enterococcus indoxyl-β-D-glucoside (mEI) plates showed that the dominant sequences recovered in our sequence libraries did not represent organisms culturable on mEI. Based on 16S rRNA gene sequencing of gull fecal isolates cultured on mEI plates, 98.8% were identified as Enterococcus spp., 1.2% were identified as Streptococcus spp., and none were identified as C. marimammalium. Illumina deep sequencing indicated that gull fecal samples harbor significantly higher proportions of C. marimammalium 16S rRNA gene sequences (>50-fold) relative to typical mEI culturable Enterococcus spp. C. marimammalium therefore can be confidently utilized as a genetic marker to identify gull fecal pollution in the beach environment. [ABSTRACT FROM AUTHOR]

Quantitative PCR (qPCR) assays targeting the host-specific Bacteroides- Prevotella 16S rRNA genetic markers have been proposed as one of the promising approaches to identify the source of fecal contamination in environmental waters. One of the concerns of qPCR assays to environmental samples is the reliability of quantified values, since DNA extraction followed by qPCR assays are usually performed without appropriate sample process control (SPC) and internal amplification controls (IACs). To check the errors in sample processing and improve the reliability of qPCR results, it is essential to evaluate the DNA recovery efficiency and PCR amplification efficiency of the target genetic markers and correct the measurement results. In this study, we constructed a genetically-engineered Escherichia coli K12 strain (designated as strain MG1655 Δlac::kan) as sample process control and evaluated the applicability to environmental water samples. The recovery efficiency of the SPC strain MG1655 Δlac::kan was similar to that of Bacteroides fragilis JCM 11019, when DNA were extracted from water samples spiked with the two bacteria. Furthermore, the SPC was included in the qPCR assays with propidium monoazide (PMA) treatment, which can exclude the genetic markers from dead cells. No significant DNA loss was observed in the PMA treatment. The inclusion of both the SPC (strain MG1655 Δlac::kan) and IAC in qPCR assays with PMA treatment gave the assurance of reliable results of host-specific Bacteroides- Prevotella 16S rRNA genetic markers in environmental water samples. [ABSTRACT FROM AUTHOR]

The risk to human health of the annual sandhill crane (Grus canadensis) migration through Nebraska, which is thought to be a major source of fecal pollution of the central Platte River, is unknown. To better understand potential risks, the presence of Campylobacter species and three fecal indicator bacterial groups (Enterococcus spp., Escherichia coli, and Bacteroidetes) was assayed by PCR from crane excreta and water samples collected during their stopover at the Platte River, Nebraska, in 2010. Genus-specific PCR assays and sequence analyses identified Campylobacter jejuni as the predominant Campylobacter species in sandhill crane excreta. Campylobacter spp. were detected in 48% of crane excreta, 24% of water samples, and 11% of sediment samples. The estimated densities ofEnterococcus spp. were highest in excreta samples (mean, 4.6 × 108 cell equivalents [CE]/g), while water samples contained higher levels of Bacteroidetes(mean, 5.1 × 105 CE/100 ml). Enterococcus spp., E. coli, and Campylobacter spp. were significantly increased in river water and sediments during the crane migration period, with Enterococcus sp. densities (∼3.3 × 105 CE/g) 2 to 4 orders of magnitude higher than those of Bacteroidetes (4.9 × 10³ CE/g), E. coli (2.2 × 10³ CE/g), and Campylobacter spp. (37 CE/g). Sequencing data for the 16S rRNA gene and Campylobacter species-specific PCR assays indicated that C. jejuni was the major Campylobacter species present in water, sediments, and crane excreta. Overall, migration appeared to result in a significant, but temporary, change in water quality in spring, when there may be a C. jejuni health hazard associated with water and crops visited by the migrating birds. [ABSTRACT FROM AUTHOR]

The objective of this study was to combine knowledge of environmental, topographical, meteorological, and anthropologic factors in the Río Grande de Arecibo (RGA) watershed in Puerto Rico with information provided by microbial source tracking (MST) to map hot spots (i.e., likely sources) of fecal contamination. Water samples were tested for the presence of human and bovine fecal contamination in addition to fecal indicator bacteria and correlated against several land uses and the density of septic tanks, sewers, and latrines. Specifically, human sources were positively correlated with developed (r = 0.68), barren land uses (r = 0.84), density of septic tanks (r = 0.78), slope (r = 0.63), and the proximity to wastewater treatment plants (WWTPs) (r = 0.82). Agricultural land, the number of upstream National Pollution Discharge Elimination System (NPDES) facilities, and density of latrines were positively associated with the bovine marker (r = 0.71; r = 0.74; and r = 0.68, respectively). Using this information, we provided a hot spot map, which shows areas that should be closely monitored for fecal contamination in the RGA watershed. The results indicated that additional bovine assays are needed in tropical regions. We concluded that meteorological, topographical, anthropogenic, and land cover data are needed to evaluate and verify the performance of MST assays and, therefore, to identify important sources of fecal contamination in environmental waters. [ABSTRACT FROM AUTHOR]

Progress toward the sanitation component of Millennium Development Goal (MDG) Target 7c was reassessed to account for the need to protect communities and the wider population from exposure to human excreta. We classified connections to sewerage as "improved sanitation" only if the sewage was treated before discharge to the environment. Sewerage connection data was available for 167 countries in 2010; of these, 77 had published data on sewage treatment prevalence. We developed an empirical model to estimate sewage treatment prevalence for 47 additional countries. We estimate that in 2010, 40% of the global population (2.8 billion people) used improved sanitation, as opposed to the estimate of 62% (4.3 billion people) from the WHO/UNICEF Joint Monitoring Programme (JMP), and that 4.1 billion people lacked access to an improved sanitation facility. Redefining sewerage-without-treatment as "unimproved sanitation" in MDG monitoring would raise the 1990 baseline population using unimproved sanitation from 53% to 64% and the corresponding 2015 target from 27% to 32%. At the current rate of progress, we estimate a shortfall of 28 percentage points (1.9 billion people) in 2010 and a projected 27 percentage point shortfall in 2015. [ABSTRACT FROM AUTHOR]

EPA Method 1600 and Enterolert are used interchangeably to measure Enterococcus for fecal contamination of public beaches, but the methods occasionally produce different results. Here we assess whether these differences are attributable to the selectivity for certain species within the Enterococcus group. Both methods were used to obtain 1279 isolates from 17 environmental samples, including influent and effluent of four wastewater treatment plants, ambient marine water from seven different beaches, and freshwater urban runoff fromtwo streamsystems.The isolateswere identified to species level. Detection of non-Enterococcus species was slightly higher using Enterolert (8.4%) than for EPA Method 1600 (5.1%). E. faecalis and E. faecium, commonly associated with human fecal waste, were predominant in wastewater; however, Enterolert had greater selectivity for E. faecalis, which was also shown using a laboratory-created sample. The same species selectivity was not observed for most beach water and urban runoff samples. These samples had relatively higher proportions of plant associated species, E. casseliflavus (18.5%) and E. mundtii (5.7%), compared to wastewater, suggesting environmental inputs to beaches and runoff. The potential for species selectivity among water testing methods should be considered when assessing the sanitary quality of beaches so that public health warnings are based on indicators representative of fecal sources. [ABSTRACT FROM AUTHOR]

Objective work has realization collection and analysis laboratory of water samples Pirapó river, main source supply of cities Maringá and Apucarana, Paraná State, with direction the presence of coliforms. Established were five points collection samples of water river (cities Maringá, Apucarana, Atalaia, Jardim Olinda and Colorado), on july 25, 2012. Samples tested, all showed contamination by coliforms and totals, and in 80% samples was impossible attainment of high function number count of colonies plate. Results indicate value high of contamination by coliforms and totals the main source of potable water supply cities of Maringá and Apucarana. [ABSTRACT FROM AUTHOR]

Health risks associated with sewage-contaminated recreational waters are of important public health concern. Reliable water monitoring systems are therefore crucial. Current recreational water quality criteria rely predominantly on the enumeration of bacterial indicators, while potentially dangerous viral pathogens often remain undetected. Human enteric viruses have been proposed as alternative indicators; however, their detection is often hindered by low viral concentrations present in the environment. Reported here are novel and effective laboratory protocols for viral concentration and highly sensitive and optimized RT-PCR for the efficient detection of enteroviruses, an important enteric virus subset, in Hawaiian environmental waters. Eighteen published enterovirus primer pairs were comparatively evaluated for detection sensitivity. The primer set exhibiting the lowest detection limit under optimized conditions, EQ-1/EQ-2, was validated in a field survey of 22 recreational bodies of water located around the island of Oahu, Hawaii. Eleven sites tested positive for enterovirus, indicating fecal contamination at these locations. As an additional means of viral concentration, shellfish were collected from 9 sample sites and subjected to dissection, RNA extraction, and subsequent RT-PCR. Shellfish tissue from 6 of 9 sites tested positive for enterovirus. The techniques implemented here are valuable resources to aid accurate reflection of microbial contamination in Hawaii's environmental waters. [ABSTRACT FROM AUTHOR]

Fecal contaminations of inland and coastal waters induce risks to human health and economic losses. To improve water management, specific markers have been developed to differentiate between sources of contamination. This study investigates the relative decay of fecal indicator bacteria (FIB, Escherichia coli and enterococci) and six human-associated markers (two bacterial markers: Bacteroidales HF183 (HF183) and Bifidobacterium adolescentis (BifAd); one viral marker: genogroup II F-specific RNA bacteriophages (FRNAPH II); three chemical markers: caffeine and two fecal stanol ratios) in freshwater and seawater microcosms seeded with human wastewater. These experiments were performed in darkness, at 20 °C and under aerobic conditions. The modeling of the decay curves allows us (i) to compare FIB and markers and (ii) to classify markers according to their persistence in seawater (FRNAPH II < HF183, stanol ratios < BifAd, caffeine) and in freshwater (HF183, stanol ratios < FRNAPH II < BifAd < caffeine). Although those results depend on the experimental conditions, this study represents a necessary step to develop and validate an interdisciplinary toolbox for the investigation of the sources of fecal contaminations. [ABSTRACT FROM AUTHOR]

Enterococcus was selected by US EPA as a Gram-positive indicator microorganism for groundwater fecal contamination. It was recently reported that enterococcal surface protein (esp) was more prevalent in Enterococcus from human sources than in Enterococcus from nonhuman sources and esp could potentially be used as a source tracking tool for fecal contamination (Scott et al., 2005). In this research, we performed laboratory column transport experiments to investigate the transport of Enterococcus faecium within saturated quartz sands. Particularly, we used a wild type strain (E1162) and a mutant (E1162Δesp) to examine the influence of esp on the transport behavior of E. faecium. Our results showed that esp could significantly enhance the attachment of E. faecium cells onto the surface of silica sands and thus lower the mobility of E. faecium within sand packs. Cell surface properties (e.g., zeta potential) were determined and the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory was applied to explain the effects of esp on the retention of E. faecium. Overall, our results suggested that E. faecium strains with esp could display lower mobility within saturated sand packs than E. faecium strains without esp. The disparity in the transport behavior of E. faecium with and without esp could limit the effectiveness of esp as a source tracking tool within the groundwater system. [ABSTRACT FROM AUTHOR]

Ponds receiving latrine effluents may serve as sources of fecal contamination to shallow aquifers tapped by millions of tube-wells in Bangladesh. To test this hypothesis, transects of monitoring wells radiating away from four ponds were installed in a shallow sandy aquifer underlying a densely populated village and monitored for 14 months. Two of the ponds extended to medium sand. Another pond was sited within silty sand and the last in silt. The fecal indicator bacterium E. coli was rarely detected along the transects during the dry season and was only detected near the ponds extending to medium sand up to 7 m away during the monsoon. A log-linear decline in E. coli and Bacteroidales concentrations with distance along the transects in the early monsoon indicates that ponds excavated in medium sand were the likely source of contamination. Spatial removal rates ranged from 0.5 to 1.3 log10/m. After the ponds were artificially filled with groundwater to simulate the impact of a rain storm, E. coli levels increased near a pond recently excavated in medium sand, but no others. These observations show that adjacent sediment grain-size and how recently a pond was excavated influence the how much fecal contamination ponds receiving latrine effluents contribute to neighboring groundwater. [ABSTRACT FROM AUTHOR]

The implementation of microbial fecal source tracking (MST) methods in drinking water management is limited by the lack of knowledge on the transport and decay of host-specific genetic markers in water sources. To address these limitations, the decay and transport of human (BacH) and ruminant (BacR) fecal Bacteroidales 16S rRNA genetic markers in a drinking water source (Lake Rådasjön in Sweden) were simulated using a microbiological model coupled to a three-dimensional hydrodynamic model. The microbiological model was calibrated using data from outdoor microcosm trials performed in March, August, and November 2010 to determine the decay of BacH and BacR markers in relation to traditional fecal indicators. The microcosm trials indicated that the persistence of BacH and BacR in the microcosms was not significantly different from the persistence of traditional fecal indicators. The modeling of BacH and BacR transport within the lake illustrated that the highest levels of genetic markers at the raw water intakes were associated with human fecal sources (on-site sewers and emergency sewer overflow). This novel modeling approach improves the interpretation of MST data, especially when fecal pollution from the same host group is released into the water source from different sites in the catchment. [ABSTRACT FROM AUTHOR]

This study aimed at evaluating the host-specificity and -sensitivity of the nifH gene marker of Methanobrevibacter smithii by screening 272 fecal and wastewater samples from 11 animal species including humans in Southeast Queensland (SEQ), Australia. In addition, environmental water samples (n = 21) were collected during the dry and wet weather conditions and tested for the presence of the nifH marker along with other sewage-associated markers, namely, enterococci surface protein (esp) found in Enterococci faecium, Bacteroides HF183, adenoviruses (AVs), and polyomaviruses (PVs). The overall host-specificity of the nifH marker to differentiate between human and animal feces was 0.96 (maximum value of 1), while the overall sensitivity of this marker in human sourced feces and wastewater was 0.81 (maximum value of 1). Among the 21 environmental water samples tested, 2 (10%), 3 (14%), 12 (57%), 6 (29%), and 6 (29%) were positive for the nifH, esp, HF183, AVs and PVs markers, respectively. The prevalence of the nifH marker in environmental water samples, however, was low compared to other markers, suggesting that the use of this marker alone may not be sensitive enough to detect fecal pollution in environmental waters. The nifH marker, however, appears to be sewage-specific in SEQ, Australia, and therefore, it is recommended that this marker should be used as an additional marker in combination with the HF183 or viral markers such as AVs or PVs for accurate and sensitive detection of fecal pollution in SEQ waterways. [ABSTRACT FROM AUTHOR]

Repetitive element sequence-based polymerase chain reaction (rep-PCR) is one of the commonest methods used to identify sources of fecal contamination of water systems. In this work, BOX-A1R-based repetitive extragenic palindromic-PCR (BOX-PCR) was used to discriminate Escherichia coli strains originating from different animals and water sources, and the suitability of the technique for bacterial source tracking (BST) was evaluated. A total of 214 strains from humans, 150 strains from animals, 55 strains from sewage and 77 strains from water bodies were analyzed by the BOX-PCR technique. When maximum similarity between the fingerprints was used, a correct classification rate of 84% was achieved for strains from human and animal sources. Furthermore, 95% of the strains found in sewage were classified as being from human sources by at least one of the four classification tools used. Classification of the strains found in water bodies in the State of São Paulo was based on the fingerprints obtained for human and animal sources. Most of the sampling sites appeared to be affected by mixed sources of fecal contamination. The use of BOX-PCR for BST could be especially valuable in developing countries, where simplicity and cost are important considerations. [Copyright &y& Elsevier]

The World Health Organization recommends that the majority of water monitoring laboratories in the world test for E. coli daily since thermotolerant coliforms and E. coli are key indicators for risk assessment of recreational waters. Recently, we developed a new SNP method for typing E. coli strains, by which human-specific genotypes were identified. Here, we report the presence of these previously described specific SNP profiles in environmental water, sourced from the Coomera River, located in South East Queensland, Australia, over a period of two years. This study tested for the presence of human-specific E. coli to ascertain whether hydrologic and anthropogenic activity plays a key role in the pollution of the investigated watershed or whether the pollution is from other sources. We found six human-specific SNP profiles and one animal-specific SNP profile consistently across sampling sites and times. We have demonstrated that our SNP genotyping method is able to rapidly identify and characterize human- and animal-specific E. coli isolates in water sources. [ABSTRACT FROM AUTHOR]

Storm water ocean outfalls discharging into recreational waters pose a human health threat because of increased potential exposure to bacteria and other pathogens. The dune infiltration system (DIS) was designed and implemented at two ocean outfall sites in response to concerns by the North Carolina Department of Transportation and the town of Kure Beach, North Carolina The systems were designed to divert storm water runoff from 1.9 ha (4.7 acre) and 3.2 ha (8.0 acre) watersheds into the beach dunes. Following construction, data were collected from 25 storms during March through October 2006. The systems captured a combined total of nearly 1,800 m3 (63,500 ft3), or 95% of the influent storm water runoff-a significant reduction of runoff volume and peak flow discharging directly onto the beach (p<0.0001). Fecal coliform and enterococci concentrations were measured in the inflowing storm water runoff and groundwater downslope of the systems. Both groundwater bacteria concentrations near the systems were significantly lower than the bacteria concentrations in the inflowing storm water (p<0.001). Furthermore, groundwater fecal coliform concentrations after implementing the DISs were statistically similar to preconstruction levels (p<0.05). The initial results are promising, and the system should be considered for more widespread use. However, further comprehensive research is recommended to more thoroughly understand the viability of the DIS as a storm water best management practice and the fate and transport of the bacteria within the dunes. [ABSTRACT FROM AUTHOR]

High fecal indicator bacterial (FIB) concentrations signal urban coastal water quality impairments that can threaten public health. However, FIB (total and fecal coliform plus Enterococcus sp.) concentrations are not specific to human waste, and thus, microbial source tracking (MST) is employed to assess public health risks and remediation alternatives. Currently, water quality diagnosis requires several simultaneous MST assays. Relatively unexplored is a community analysis approach for MST where the overall microbial community composition is compared, through multivariate analysis, to link sources and sinks of microbial pollution. In this research, an urban coastal creek and drain sampling transect, previously diagnosed as human-waste-contaminated, were evaluated for bacterial community composition relative to fecal sources; a laboratory spiking study was also performed to assess method sensitivity and specificity. Multivariate statistical analysis of community profiles clearly distinguished different fecal sources, indicated a high sensitivity for sewage spikes, and confirmed creek contamination sources. This work demonstrates that molecular microbial community analysis combined with appropriate multivariate statistical analyses is an effective addition to the MST tool box. [ABSTRACT FROM AUTHOR]

Boiling is the most common method of disinfecting water in the home and the benchmark against which other point-of-use water treatment is measured. In a six-week study in peri-urban Zambia, we assessed the microbiological effectiveness and potential cost of boiling among 49 households without a water connection who reported "always" or "almost always" boiling their water before drinking it. Source and household drinking water samples were compared weekly for thermotolerant coliforms (TTC), an indicator of fecal contamination. Demographics, costs, and other information were collected through surveys and structured observations. Drinking water samples taken at the household (geometric mean 7.2 TTC/100 mL, 95% CI, 5.4-9.7) were actually worse in microbiological quality than source water (geometric mean 4.0 TTC/100 mL, 95% CI, 3.1-5.1) (p < 0.001), although both are relatively low levels of contamination. Only 60% of drinking water samples were reported to have actually been boiled at the time of collection from the home, suggesting over-reporting and inconsistent compliance. However, these samples were of no higher microbiological quality. Evidence suggests that water quality deteriorated after boiling due to lack of residual protection and unsafe storage and handling. The potential cost of fuel or electricity for boiling was estimated at 5% and 7% of income, respectively. In this setting where microbiological water quality was relatively good at the source, safe-storage practices that minimize recontamination may be more effective in managing the risk of disease from drinking water at a fraction of the cost of boiling. [ABSTRACT FROM AUTHOR]

The article offers information on the study that focuses on the source tracking faecal contamination in an urbanized and a rural waterway in the Nelson-Tasman region, New Zealand. It offers an outline of the methods used in the research including marker validation, and field microbial source tracking (MST) study.

Septic systems that are built in compliance with regulations are generally not expected to be the cause of groundwater borne disease outbreaks, especially in areas with thick vadose zones. However, this case study demonstrates that a disease outbreak can occur in such a setting and outlines the combination of epidemiological, microbiological, and hydrogeological methods used to confirm the source of the outbreak. In early June 2007, 229 patrons and employees of a new restaurant in northeastern Wisconsin were affected by acute gastroenteritis; 6 people were hospitalized. Epidemiological case-control analysis indicated that drinking the restaurant's well water was associated with illness (odds ratio = 3.2, 95% confidence interval = 0.9 to 11.4, P = 0.06). Microbiological analysis (quantitative reverse transcription-polymerase chain reaction) measured 50 genomic copies per liter of norovirus genogroup I in the well water. Nucleotide sequencing determined the genotype as GI.2 and further showed the identical virus was present in patrons' stool specimens and in the septic tank. Tracer tests using dyes injected at two points in the septic system showed that effluent was traveling from the tanks (through a leaking fitting) and infiltration field to the well in 6 and 15 d, respectively. The restaurant septic system and well (85-m deep, in a fractured dolomite aquifer) both conformed to state building codes. The early arrival of dye in the well, which was 188 m from the septic field and located beneath a 35-m thick vadose zone, demonstrates that in highly vulnerable hydrogeological settings, compliance with regulations may not provide adequate protection from fecal pathogens. [ABSTRACT FROM AUTHOR]

Background: The current criteria for recreational water quality evaluation are primarily based on measurements of fecal indicator bacteria growth. However, these criteria often fail to predict the presence of waterborne human pathogenic viruses. To explore the possibility of direct use of human enteric viruses as improved human fecal contamination indicators, human adenovirus (HAdV) was tested as a model in this study. Findings: In order to establish a highly sensitive protocol for effective detection of HAdV in aquatic environments, sixteen published PCR primer sets were re-optimized and comparatively evaluated. Primer sets nehex3deg/ nehex4deg, ADV-F/ADV-R, and nested PCR primer sets hex1deg/hex2deg and nehex3deg/nehex4deg were identified to be the most sensitive ones, with up to 1,000 fold higher detection sensitivity compared to other published assays. These three PCR protocols were successfully employed to detect HAdV in both treated and untreated urban wastewaters, and also in 6 of 16 recreational water samples collected around the island of Oahu, Hawaii. Conclusions: Findings from this study support the possible use of enteric viruses for aquatic environmental monitoring, specifically for the essential routine monitoring of Hawaiian beach waters using the optimized PCR protocol to detect HAdV at certain water sites to ensure a safe use of recreational waters. [ABSTRACT FROM AUTHOR]

Fecal contamination of water bodies causes a public health problem and economic loss. To control such contamination management actions need to be guided by sound science. From 2007–2009 a study was undertaken to determine the sources of fecal bacteria contamination to the marine waters adjoining the Town of Wrightsville Beach, North Carolina, USA. The research effort included sampling for fecal coliform and Enterococcus bacteria, sampling for optical brighteners, dye studies, and use of molecular bacterial source tracking techniques including polymerase chain reaction (PCR) and terminal restriction fragment polymorphism (T-RFLP) fingerprinting of the Bacteroides–Prevotella group. Of the 96 samples collected from nine locations during the study, the water contact standard for Enterococcus was exceeded on 13 occasions. The T-RFLP fingerprint analyses demonstrated that the most widespread source of fecal contamination was human, occurring in 38% of the samples, with secondary ruminant and avian sources also detected. Optical brightener concentrations were low, reflecting a lack of sewage line leakage or spills. A lack of sewer leaks and lack of septic systems in the town pointed toward discharge from boat heads into the marine waters as the major cause of fecal contamination; this was supported by dye studies. Based on these data, the Town initiated action to have the U.S. Environmental Protection Agency declare the coastal waters (out to 3 nautical miles), the nearby Atlantic Intracoastal Waterway and its tributaries a no-discharge zone (NDZ) to alleviate the human fecal pollution. The Town garnered supporting resolutions from other local communities who jointly petitioned the North Carolina Department of Environmental and Natural Resources. This State regulatory agency supported the local government resolutions and sent an application for an NDZ to the EPA in April 2009. The EPA concurred, and in February 2010 the coastal waters of New Hanover County, NC, became the first marine area on the U.S. eastern seaboard between Delaware and the Florida Keys to be declared a no-discharge zone. [Copyright &y& Elsevier]

While many current microbial source tracking (MST) methods rely on the use of specific molecular marker genes to identify sources of fecal contamination, these methods often fail to determine all point and nonpoint contributors of fecal inputs into waterways. In this study, we developed a new library-dependent MST method that uses pyrosequencing-derived shared operational taxonomy units (OTUs) to define sources of fecal contamination in waterways. A total 56,841 pyrosequencing reads of 16S rDNA obtained from the feces of humans and animals were evaluated and used to compare fecal microbial diversity in three freshwater samples obtained from the Yeongsan river basin in Jeonnam Province, South Korea. Sites included an urbanized agricultural area (Y1) (Escherichia coli counts ≥ 1600 CFU/100 mL), an open area (Y2) with no major industrial activities (940 CFU/100 mL), and a typical agricultural area (Y3) (= 1600 CFU/100 mL). Data analyses indicated that the majority of bacteria in the feces of humans and domesticated animals were comprised of members of the phyla Bacteroidetes or Firmicutes, whereas the majority of bacteria in wild goose feces and freshwater samples were classified to the phylum Proteobacteria. Analysis of OTUs shared between the fecal and environmental samples suggested that the potential sources of the fecal contamination at the sites were of human and swine origin. Quantification of fecal contamination was also examined by comparing the density of pyrosequencing reads in each fecal sample within shared OTUs. Taken together, our results indicated that analysis of shared OTUs derived from barcoded pyrosequencing reads provide the necessary resolution and discrimination to be useful as a next generation platform for microbial source tracking studies. [ABSTRACT FROM AUTHOR]

Abstract: In this study, data from bacterial source tracking (BST) analysis using antibiotic resistance profiles were examined using two statistical techniques, Random Forests (RF) and discriminant analysis (DA) to determine sources of fecal contamination of a Texas water body. Cow Trap and Cedar Lakes are potential oyster harvesting waters located in Brazoria County, Texas, that have been listed as impaired for bacteria on the 2004 Texas 303(d) list. Unknown source Escherichia coli were isolated from water samples collected in the study area during two sampling events. Isolates were confirmed as E. coli using carbon source utilization profiles and then analyzed via ARA, following the Kirby–Bauer disk diffusion method. Zone diameters from ARA profiles were analyzed with both DA and RF. Using a two-way classification (human vs nonhuman), both DA and RF categorized over 90% of the 299 unknown source isolates as a nonhuman source. The average rates of correct classification (ARCCs) for the library of 1172 isolates using DA and RF were 74.6% and 82.3%, respectively. ARCCs from RF ranged from 7.7 to 12.0% higher than those from DA. Rates of correct classification (RCCs) for individual sources classified with RF ranged from 23.2 to 0.2% higher than those of DA, with a mean difference of 9.0%. Additional evidence for the outperformance of DA by RF was found in the comparison of training and test set ARCCs and examination of specific disputed isolates; RF produced higher ARCCs (ranging from 8 to 13% higher) than DA for all 1000 trials (excluding the two-way classification, in which RF outperformed DA 999 out of 1000 times). This is of practical significance for analysis of bacterial source tracking data. Overall, based on both DA and RF results, migratory birds were found to be the source of the largest portion of the unknown E. coli isolates. This study is the first known published application of Random Forests in the field of BST. [Copyright &y& Elsevier]

Abstract: This study reveals land-use factors that explain stream water quality during wet and dry weather conditions in a large river basin using two different linear models-multiple linear regression (MLR) models and constrained least squares (CLS) models. Six land-use types and three topographical parameters (size, slope, and permeability) of the watershed were incorporated into the models as explanatory variables. The suggested models were then demonstrated using a digitized elevation map in conjunction with the land-use and the measured concentration data for Escherichia coli (EC), Enterococci bacteria (ENT), and six heavy metal species collected monthly during 2007–2008 at 50 monitoring sites in the Yeongsan Watershed, Korea. The results showed that the MLR models can be a powerful tool for predicting the average concentrations of pollutants in stream water (the Nash-Sutcliffe (NS) model efficiency coefficients ranged from 0.67 to 0.95). On the other hand, the CLS models, with moderately good prediction performance (the NS coefficients ranged 0.28–0.85), were more suitable for quantifying contributions of respective land-uses to the stream water quality. The CLS models suggested that industrial and urban land-uses are major contributors to the stream concentrations of EC and ENT, whereas agricultural, industrial, and mining areas were significant sources of many heavy metal species. In addition, the slope, size, and permeability of the watershed were found to be important factors determining the extent of the contribution from each land-use type to the stream water quality. The models proposed in this paper can be considered useful tools for developing land cover guidelines and for prioritizing locations for implementing management practices to maintain stream water quality standard in a large river basin. [Copyright &y& Elsevier]

As a representative urban stream in Korea, the Gwangju (GJ) stream suffers from chronic fecal contamination. In this study, to characterize levels of fecal pollution in the GJ stream, the monthly monitoring data for seven years (from 2001 to 2007) and the hourly monitoring data from two field experiments were examined with respect to seasonal/daily variations and spatial distribution under wet and dry weather conditions. This research revealed that concentrations of fecal indicator bacteria strongly varied depending on the prevalent meteorological conditions. That is, during the dry daytime, fecal indicator bacteria concentrations decreased due to inactivation from solar irradiation, but rapidly increased in the absence of sunlight, suggesting external source inputs. In addition, bacterial concentrations substantially increased during rainfall events, due probably to a major contribution from combined sewer overflow. The observations in this study can be useful for implementing fecal pollution management strategies and for predicting fecal contamination as a function of meteorological conditions. [ABSTRACT FROM AUTHOR]

Almost half of the world's population relies on non-networked water supply services, which necessitates in-home water storage. It has been suggested that dirty hands play a role in microbial contamination of drinking water during collection, transport, and storage. However, little work has been done to evaluate quantitatively the association between hand contamination and stored water quality within households. This study measured levels of E. coli, fecal streptococci, and occurrence of the general Bacteroidales fecal DNA marker in source water, in stored water, and on hands in 334 households among communities in Dar es Salaam, Tanzania, where residents use non-networked water sources. Levels of fecal contamination on hands of mothers and children were positively correlated to fecal contamination in stored drinking water within households. Household characteristics associated with hand contamination included mother's educational attainment, use of an improved toilet, an infant in the household, and dissatisfaction with the quantity of water available for hygiene. In addition, fecal contamination on hands was associated with the prevalence of gastrointestinal and respiratory symptoms within a household. The results suggest that reducing fecal contamination on hands should be investigated as a strategy for improving stored drinking water quality and health among households using non-networked water supplies. [ABSTRACT FROM AUTHOR]

Human and animal fecal pollution of the environment presents a risk to human health because of the presence of pathogenic viruses and bacteria. To distinguish between human and animal sources of pollution, we designed specific real-time reverse transcription (RT)-PCR assays for human and animal enteric viruses, including norovirus genogroups I, II, and III; porcine adenovirus types 3 and 5; ovine adenovirus; atadeno- virus; and human adenovirus species C and F, which are excreted by infected humans, pigs, cattle, sheep, deer, and goats, and for the detection of F+ RNA bacteriophage genogroups I to IV, which are associated with human and animal wastes. The sensitivity of this viral toolbox (VTB) was tested against 10-fold dilution series of DNA plasmids that carry the target sequences of the respective viruses and was shown to detect at least 10 plasmid copies for each assay. A panel of human and animal enteric and respiratory viruses showed these assays to be highly sensitive and specific to their respective targets. The VTB was used to detect viruses in fecal and environmental samples, including raw sewage and biosolids from municipal sewage treatment plants, abattoir sewage, and fecally contaminated shellfish and river water, which were likely to contain animal or human viruses. [ABSTRACT FROM AUTHOR]

Fecal indicator bacteria (FIB) have long been used as a marker of fecal pollution in surface waters subject to point source and non-point source discharges of treated or untreated human waste. In this paper, we set out to determine the source(s) of elevated FIB concentrations in Cucamonga Creek, a concrete-lined urban stream in southern California. Flow in the creek consists primarily of treated and disinfected wastewater effluent, mixed with relatively smaller but variable flow of runoff from the surrounding urban landscape. Dry and wet weather runoff contributes nearly 100% of FIB loading to Cucamonga Creek, while treated wastewater contributes significant loading of nutrients, including dissolved organic carbon (DOC), phosphorus, nitrate, and ammonium. FIB concentrations are strongly positively correlated with DOC concentration in runoff (Spearman's ρ ≥ 0.66, P ≤ 0.037), and microcosm studies reveal that the survival of Escherichia coli and enterococci bacteria in runoff is strongly dependent on the concentration of both DOC and phosphorus. Below threshold concentrations of 7 and 0.07 mg/L, respectively, FIB die off exponentially (die-off rate 0.09 h-1). Above these thresholds, FIB either grow exponentially (growth rate 0.3 h-1) or exhibit a periodic steady-state in which bacterial concentrations fluctuate around some mean value. The periodic steady-state pattern is consistent with a Lotka—Volterra predator—prey oscillation model, and the clearance rate (20 μL predator-1 h-1) obtained by fitting the model to our data is consistent with the hypothesis that predacious protozoa regulate FIB concentrations in runoff at high DOC concentrations. Collectively, these results indicate that FIB impairment of Cucamonga Creek is best viewed as an ecological phenomenon characterized by both bottom-up and top-down control. [ABSTRACT FROM AUTHOR]

In this study, we evaluated the specificity, distribution, and sensitivity of Prevotella strain-based (PF163 and PigBac1) and methanogen-based (P23-2) PCR assays proposed to detect swine fecal pollution in environmental waters. The assays were tested against 222 fecal DNA extracts derived from target and nontarget animal hosts and against 34 groundwater and 15 surface water samples from five different sites. We also investigated the phylogenetic diversity of 1,340 "Bacteroidales" 16S rRNA gene sequences derived from swine feces, swine waste lagoons, swine manure pits, and waters adjacent to swine operations. Most swine fecal samples were positive for the host-specific Prevotella-based PCR assays (80 to 87%), while fewer were positive with the methanogen-targeted PCR assay (53%). Similarly, the Prevotella markers were detected more frequently than the methanogen-targeted assay markers in waters historically impacted with swine fecal contamination. However, the PF163 PCR assay cross-reacted with 23% of nontarget fecal DNA extracts, although Bayesian statistics suggested that it yielded the highest probability of detecting pig fecal contamination in a given water sample. Phylogenetic analyses revealed previously unknown swine-associated clades comprised of clones from geographically diverse swine sources and from water samples adjacent to swine operations that are not targeted by the Prevotella assays. While deeper sequencing coverage might be necessary to better understand the molecular diversity of fecal Bacteroidales species, results of sequence analyses supported the presence of swine fecal pollution in the studied watersheds. Overall, due to nontarget cross amplification and poor geographic stability of currently available host-specific PCR assays, development of additional assays is necessary to accurately detect sources of swine fecal pollution. [ABSTRACT FROM AUTHOR]

In the United States, total maximum daily load standards for bodies of water that do not meet bacterial water quality standards are set by each state. The presence of human polyomaviruses (HPyVs) can be used as an indicator of human-associated sewage pollution in these waters. We have developed and optimized a TaqMan quantitative PCR (QPCR) assay based on the conserved T antigen to both quantity and simultaneously detect two HPyVs; JC virus and BK virus. The QPCR assay was able to consistently quantify ≥10 gene copies per reaction and is linear over 5 orders of magnitude. HPyVs were consistently detected in human waste samples (57 of 64) and environmental waters with known human fecal contamination (5 of 5) and were not amplified in DNA extracted from 127 animal waste samples from 14 species. HPyV concentrations in sewage decreased 81.2 and 84.2% over 28 days incubation at 25 and 35°C, respectively. HPyVs results were compared to Escherichia coli, fecal coliform, and enterococci concentrations and the presence of three other human-associated microbes: Bacteroidetes, Methanobrevibacter smithii,and adenovirus. HPyVs were the most frequently detected of these in human and contaminated environmental samples and were more human specific than the Bacteroidetes (HF183) or M. smithii. HPyVs and M. smithii more closely mimicked the persistence of adenovirus in sewage than the other microbes. The use of this rapid and quantitative assay in water quality research could help regulatory agencies to identify sources of water pollution for improved remediation of contaminated waters and ultimately protect humans from exposure to pathogens. [ABSTRACT FROM AUTHOR]