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Increasing urbanisation and industrialisation of the Visakhapatnam region have brought domestic sewage and industrial wastewater discharge into the coastal ocean. This study examines the indicator and pathogenic bacteria's quantitative abundance and antibiotic susceptibility. This study collected surface and subsurface water samples from ten different regions (147 stations; 294 samples), including 12 industrial discharge points, surrounding stations and two harbours from the coast of Pydibheemavaram to Tuni. Physicochemical parameters like salinity, temperature, fluorescence, pH, total suspended matter, nutrients, chlorophyll-a and dissolved oxygen showed a difference between regions. We noticed the presence of indicator (Escherichia coli and Enterococcus faecalis) and pathogenic (Aeromonas hydrophila, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Salmonella and Shigella, Vibrio cholera and Vibrio parahaemolyticus) bacteria among the samples. Waters from the near harbour and Visakhapatnam steel plant showed lower bacterial load with no direct input from industries to the coastal water. Samples collected during the industrial discharge period had a higher bacterial load, including E. coli. Enteric bacteria were found in higher numbers at most stations. Some isolates were resistant to multiple antibiotics with higher antibiotic resistance and multiple antibiotic resistance indexes compared with the other coastal water habitats in the Bay of Bengal. The occurrence of these bacteria above the standard limits and with multiple antibiotic resistance in the study region may pose a potential threat to the local inhabitants. It can create an alarming situation in the coastal waters in the study region., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Plastics have been proposed as vectors of bacteria as they act as a substrate for biofilms. In this study, we evaluated the abundance of faecal and marine bacteria and antibiotic resistance genes (ARGs) from biofilms adhered to marine plastics. Floating plastics and plastics from sediments were collected in coastal areas impacted by human faecal pollution in the northwestern Mediterranean Sea. Culture and/or molecular methods were used to quantify faecal indicators (E. coli, Enterococci and crAssphage), and the ARGs sulI, tetW and bla TEM and the 16S rRNA were detected by qPCR assays. Pseudomonas and Vibrio species and heterotrophic marine bacteria were also analysed via culture-based methods. Results showed that, plastic particles covered by bacterial biofilms, primarily consisted of marine bacteria including Vibrio spp. Some floating plastics had a low concentration of viable E. coli and Enterococci (42% and 67% of the plastics respectively). Considering the median area of the plastics, we detected an average of 68 cfu E. coli per item, while a higher concentration of E. coli was detected on individual plastic items, when compared with 100 ml of the surrounding water. Using qPCR, we quantified higher values of faecal indicators which included inactive and dead microorganisms, detecting up to 2.6 × 10 2 gc mm -2 . The ARGs were detected in 67-88% of the floating plastics and in 29-57% of the sediment plastics with a concentration of up to 6.7 × 10 2 gc mm -2 . Furthermore, enrichment of these genes was observed in biofilms compared with the surrounding water. These results show that floating plastics act as a conduit for both the attachment and transport of faecal microorganisms. In contrast, low presence of faecal indicators was detected in plastic from seafloor sediments. Therefore, although in low concentrations, faecal bacteria, and potential pathogens, were identified in marine plastics, further suggesting plastics act as a reservoir of pathogens and ARGs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Colistin is one of the antibiotics of last resort for human health. However, the dissemination of the plasmid-mediated colistin resistance gene mcr-1 is of great concern globally. In the One Health framework, the environment is an important component for managing antimicrobial resistance. However, little information is available concerning the prevalence of mcr-1 in water environments. We aimed to reveal the prevalence of mcr-1 in different water environments in Hanoi, Vietnam. Quantitative PCR was applied to detect mcr-1 in four urban drainages receiving untreated domestic wastewater, three rivers, five lakes and two groundwater samples. Urban drainages contained higher concentrations of mcr-1, suggesting that urban residents carry the gene. The class 1 integron-integrase gene was identified as a good surrogate of antibiotic resistance genes including mcr-1. A significant correlation was found between the levels of mcr-1 and the human-specific cross-assembly phage, which is an indicator of human faecal pollution. These results indicated that the primary source of mcr-1 in urban water environments is human faeces, which is consistent with the fact that most domestic wastewater is untreated in Hanoi. The control of untreated wastewater is critical for alleviating the spread of mcr-1 in water environments in Vietnam., (© 2020 The Society for Applied Microbiology.)

Characterising faecal indicator organism (FIO) survival in the environment is important for informing land management and minimising public health risk to downstream water users. However, key gaps in knowledge include understanding how wildlife contribute to catchment-wide FIO sources and how FIO survival is affected by low environmental temperatures. The aim of this study was to quantify E. coli and intestinal enterococci die-off in dairy cow versus red deer faecal sources exposed to repeated freeze-thaw cycles under controlled laboratory conditions. Survival of FIOs in water exposed to freeze-thaw was also investigated to help interpret survival responses. Both E. coli and intestinal enterococci were capable of surviving sub-freezing conditions with the faeces from both animals able to sustain relatively high FIO concentrations, as indicated by modelling, and observations revealing persistence in excess of 11 days and in some cases confirmed beyond 22 days. Die-off responses of deer-derived FIOs in both faeces and water exposed to low temperatures provide much needed information to enable better accounting of the varied catchment sources of faecal pollution and results from this study help constrain the parameterisation of die-off coefficients to better inform more integrated modelling and decision-making for microbial water quality management.

ColiSense, an early warning system developed for Escherichia coli detection, is assessed using environmental samples. The system relies on the detection of β-glucuronidase (GUS), a biomarker enzyme for E. coli. In contrast with other rapid GUS-based methods, ColiSense is the only method that uses 6-chloro-4-methyl-umbelliferyl-β-D-glucuronide (6-CMUG) as a fluorogenic substrate. The system measures a direct kinetic response of extracted GUS, and the detection was carried out in the absence of particles or bacteria. It is necessary to evaluate the system with environmental samples to establish the relationship between faecal indicator bacteria E. coli and the response measured by the ColiSense. This paper presents the results of tests carried out with the ColiSense system for 2 trials, one conducted with freshwater samples collected from rivers in the Dublin area and a second conducted with seawater samples from coastal areas collected over the bathing season. A positive linear correlation was found between E. coli (MPN 100 mL -1 ) and ColiSense response (R 2  = 0.85, N = 125, p < 0.01) for the seawater sample. A ColiSense response threshold was identified as 0-1.8 pmol min -1 100 mL -1 , equivalent to 0-500 E. coli 100 mL -1 . Using this threshold, 96.8% of the samples were correctly classified as being above or below 500 E. coli 100 mL -1 by the ColiSense system. Results presented demonstrate that the ColiSense system can be used as an early warning tool with potential for active management of bathing areas by providing results in 75 min from sample collection.

Recent studies have shown that crAssphage is abundant in human faecal samples worldwide. It has thus been postulated as a potential microbial source tracking (MST) marker to detect human faecal pollution in water. However, an effective implementation of crAssphage in water management strategies will depend on an understanding of its environmental dynamics. In this work, the abundance and temporal distribution of crAssphage was analysed in the effluent of wastewater treatment plants using different sewage treatments, and in two rivers (water and sediments) that differ in pollution impact and flow regime. Additionally, the influence of environmental conditions (temperature and rainfall) on the removal of the marker was studied along a river section, and natural inactivation was assessed by a mesocosms approach. Molecular and culture-based tools were used to compare crAssphage abundance and dynamics with those of bacteria and bacteriophages currently applied as global indicators (E. coli, somatic coliphages, Bacteroides GA17 bacteriophages, and the human-associated MST markers HF183 and HMBif). CrAssphage concentrations in sewage effluent and river samples were similar to those of HF183 and HMBif and higher than other general and/or culture-based indicators (by 2-3 orders of magnitude). Measurement of crAssphage abundance revealed no temporal variability in the effluent, although rainfall events affected the dynamics, possibly through the mobilisation of sediments, where the marker was detected in high concentrations, and an increase in diffuse and point pollution. Another factor affecting crAssphage inactivation was temperature. Its persistence was longer compared with other bacterial markers analysed by qPCR but lower than culturable markers. The results of this study support the use of crAssphage as a human source tracking marker of faecal pollution in water, since it has similar abundances to other molecular human MST markers, yet with a longer persistence in the environment. Nevertheless, its use in combination with infectious bacteriophages is probably advisable., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Many South Africans living in resource-poor settings with little or no access to pipe-borne water still rely on rivers as alternative water sources for drinking and other purposes. The poor microbial quality of such water bodies calls for appropriate monitoring. However, routine monitoring only takes into consideration the microbial quality of the water column, and does not include monitoring of the riverbed sediments for microbial pollution. This study sought to investigate the microbial quality of riverbed sediments in the Apies River, Gauteng Province, South Africa, using Escherichia coli as a faecal indicator organism and to investigate the impact of seasonal variation on its abundance. Weekly samples were collected at 10 sampling sites on the Apies River between May and August 2013 (dry season) and between January and February 2014 (wet season). E. coli was enumerated using the Colilert®-18 Quanti-Tray® 2000 system. All sites tested positive for E. coli. Wastewater treatment work effluents had the highest negative impact on the river water quality. Seasonal variations had an impact on the concentration of E. coli both in water and sediments with concentrations increasing during the wet season. A strong positive correlation was observed between temperature and the E. coli concentrations. We therefore conclude that the sediments of the Apies River are heavily polluted with faecal indicator bacteria and could also harbour other microorganisms including pathogens. The release of such pathogens into the water column as a result of the resuspension of sediments due to extreme events like floods or human activities could increase the health risk of the populations using the untreated river water for recreation and other household purposes. There is therefore an urgent need to reconsider and review the current South African guidelines for water quality monitoring to include sediments, so as to protect human health and other aquatic lives., (Copyright © 2015 Elsevier B.V. All rights reserved.)

A safe water supply is a necessity, but it remains one of the backlogs of services rendered in rural areas of developing countries. This leads to vulnerable communities using water from available sources that is unsafe as it is contaminated with faecal matter. Microbial source tracking (MST) methods are gold-standard techniques that detect the exact sources of faecal contamination. This study, therefore, tracked and identified the exact sources of faecal contamination from the catchment to the point of use in rural areas of Vhembe District Municipality. Collected water samples (n = 1048) were concentrated by membrane filtration for the enumeration and detection of E. coli, followed by DNA extraction. The extracted DNA was subjected to a quantitative polymerase chain reaction (qPCR) to track target host-specific Bacteroidales genetic markers from the water source to the point of use. Rivers and dams exhibited maximum E. coli counts of up to 90 CFU/100 mL during the wet season and up to 50 CFU/100 mL during the dry season. Due to the effective treatment of these water sources, no E. coli bacteria were detected in any of the sampled municipal drinking water treatment plants at the point of treatment, while this indicator bacterium was detected at the point of use (households), with a maximum of 4 CFU/100 mL recorded during both the wet and dry seasons. Overall, the most prevalent MST marker exhibited during the wet season was BacCan (dog-associated, 6.87%), followed by BacCow (cow-associated, 5.53%), while Pig-2-Bac (pig-associated, 2.48%) was the least prevalent. The most prevalent marker exhibited during the dry season was BacCan (5.34%), followed by BacCow, with Pig-2-Bac (1.72%) being the least prevalent. A positive correlation (r = 0.31, p = 0.001) was established between the presence of the MST markers and detected E. coli from water sources to the point of use. The knowledge of the faecal contamination attributes in both public and domestic domains will assist in developing prevention and control strategies. [ABSTRACT FROM AUTHOR]

The Danube River is, at 2857 km, the second longest river in Europe and the most international river in the world with 19 countries in its catchment. Along the entire river, faecal pollution levels are mainly influenced by point-source emissions from treated and untreated sewage of municipal origin under base-flow conditions. In the past 2 decades, large investments in wastewater collection and treatment infrastructure were made in the European Union (EU) Member States located in the Danube River Basin (DRB). Overall, the share of population equivalents with appropriately biologically treated wastewater (without disinfection) has increased from 69% to more than 85%. The proportion of tertiary treatment has risen from 46 to 73%. In contrast, no comparable improvements of wastewater infrastructure took place in non-EU Member States in the middle and lower DRB, where a substantial amount of untreated wastewater is still directly discharged into the Danube River. Faecal pollution levels along the whole Danube River and the confluence sites of the most important tributaries were monitored during four Danube River expeditions, the Joint Danube Surveys (JDS). During all four surveys, the longitudinal patterns of faecal pollution were highly consistent, with generally lower levels in the upper section and elevated levels and major hotspots in the middle and lower sections of the Danube River. From 2001 to 2019, a significant decrease in faecal pollution levels could be observed in all three sections with average reduction rates between 72 and 86%. Despite this general improvement in microbiological water quality, no such decreases were observed for the highly polluted stretch in Central Serbia. Further improvements in microbiological water quality can be expected for the next decades on the basis of further investments in wastewater infrastructure in the EU Member States, in the middle and lower DRB. In the upper DRB, and due to the high compliance level as regards collection and treatment, improvements can further be achieved by upgrading sewage treatment plants with quaternary treatment steps as well as by preventing combined sewer overflows. The accession of the Western Balkan countries to the EU would also significantly boost investments in wastewater infrastructure and water quality improvements in the middle section of the Danube. Continuing whole-river expeditions such as the Joint Danube Surveys is highly recommended to monitor the developments in water quality in the future. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the seasonal variation of microbial quality in urban waterbodies along urbanization gradients. Bimonthly samples were collected from 14 recreational lakes and flood mitigation ponds in the Klang Valley, Malaysia, between May and October 2017. Samples were analysed for the presence and abundance of Escherichia coli, Clostridium perfringens, faecal coliforms (FC), faecal streptococci (FS), enterococci and total coliforms as indicator organisms, using standard methods. All studied lakes contained indicator bacteria that exceeded the National Lake Water Quality Standards (NLWQS) to varying degrees. The mean of the FC/FS ratios in all lakes exceeded four, indicating that the faecal contamination might have originated from human sources. Escherichia coli, C. perfringens and faecal coliform concentrations were negatively correlated with temperature (P < 0.01) and positively correlated with turbidity and suspended solids (P < 0.05). Non-parametric test results revealed that only the density of C. perfringens varied significantly according to season and urbanization impacts (P < 0.05). The Secchi depth transparency and dissolved oxygen (DO) levels explain the largest variation in bacterial communities. This study showed that contamination of faecal bacteria in the waterbodies varied spatially and temporally along urbanization gradients. Water quality monitoring and improvements are needed before the waterbodies can be used for direct body-contact recreation and as alternative water sources for drinking purposes. [ABSTRACT FROM AUTHOR]

Aims: Evaluate the T90 and compare the decay of different faecal indicator bacteria (FIB) and molecular microbial source tracking (MST) markers of human and animal sources during summer and winter. Methods and Results: The persistence of Escherichia coli and enterococci and several MST molecular markers targeting host‐specific Bifidobacterium and Bacteroidales species (BifHM, BifCW, BifPL, HF183/BFD, Rum2Bac and Pig2Bac) was assessed at the same time using mesocosms. Dialysis bags filled with diluted wastewater from different sources were kept in an outdoor water tank and monitored regularly to assess the inactivation rates. The T90 values of E. coli by culture methods ranged from 1·52 to 5·69 days in summer and 2·06 to 6·19 days in winter, whereas with qPCR 2·29–4·23 days in summer and 4·17–8·09 days in winter. T90 values for enterocci ranged from 1·15 to 3·10 days in summer and from 3·01 to 5·46 days in winter. Significant differences were observed between faecal sources for both markers. For the MST makers similar T90 values were obtained in summer (1·05–1·91 days), whereas higher variability was observed in winter (2·90–6·12 days). Conclusions: Different decay rates were observed for the FIB from the different sources, especially for E. coli in ruminant samples. A higher variability among T90 values of the different MST markers in winter was observed, whereas similar T90 values were detected in summer highlighting the stronger effect of environmental parameters during this season. Significance and Impact of the Study: The diverse inactivation rates observed in bacteria from different faecal sources have implications when these rates are used to model faecal pollution in water. The use of FIBT90 of different sources is essential to develop reliable predictive models. Since different inactivation of E. coli regarding the source of pollution has been observed, the source of the pollution has to be considered for modelling approaches. [ABSTRACT FROM AUTHOR]

EC Regulation 854/2004 requires the classification of bivalve mollusc harvesting areas according to the faecal pollution status of sites. It has been reported that determination of Escherichia coli in bivalve shellfish is a poor predictor of norovirus (NoV) contamination in individual samples. We explore the correlation of shellfish E. coli data with norovirus presence using data from studies across 88 UK sites (1,184 paired samples). We investigate whether current E. coli legislative standards could be refined to reduce NoV infection risk. A significant relationship between E. coli and NoV was found in the winter months (October to February) using data from sites with at least 10 data pairs (51 sites). We found that the ratio of arithmetic means (log10 E. coli to log10 NoV) at these sites ranged from 0.6 to 1.4. The lower ratios (towards 0.6) might typically indicate situations where the contribution from UV disinfected sewage discharges was more significant. Conversely, higher ratios (towards 1.4) might indicate a prevalence of animal sources of pollution; however, this relationship did not always hold true and so further work is required to fully elucidate the factors of relevance. Reducing the current class B maximum (allowed in 10% of samples) from 46,000 E. coli per 100 g (corresponding NoV value of 75750±103) to 18,000 E. coli per 100 g (corresponding NoV value of 29365±69) reduces maximum levels of NoV by a factor of 2.6 to 1; reducing the upper class B limit to 100% compliance with 4,600 E. coli per 100 g (corresponding NoV value of 7403±39) reduces maximum levels of NoV by a factor of 10.2 to 1. We found using the UK filtered winter dataset that a maximum of 200 NoV corresponded to a maximum of 128±7 E. coli per 100 g. A maximum of 1,000 NoV corresponded to a maximum of 631±14 E. coli per 100 g. [ABSTRACT FROM AUTHOR]

This article describes a methodology for optimising predictive models for concentrations of faecal indicator organisms (FIOs) in coastal areas based on geographic and meteorological characteristics of upstream catchments. Concentrations of FIOs in mussels and water sampled from 50 sites in the south of Brazil from 2012 to 2013 were used to develop models to separately predict the spatial and temporal variations of FIOs. The geographical parameters used in predictive models for the spatial variation of FIOs were human population, urban area, percentage of impervious cover and total catchment area. The R 2 of models representing catchments located within 3.1 km from the monitoring points was up to 150% higher than that for the nearest catchment. The temporal variation of FIOs was modelled considering the combined effect of meteorological parameters and different time windows. The explained variance in models based on rainfall and solar radiation increased up to 155% and 160%, respectively. [ABSTRACT FROM AUTHOR]

Detection of enzymatic activities has been proposed as a rapid surrogate for the culture-based microbiological pollution monitoring of water resources. This paper presents the results of tests on four fully automated prototype instruments for the on-site monitoring of beta- d -glucuronidase (GLUC) activity. The tests were performed on sediment-laden stream water in the Hydrological Open Air Laboratory (HOAL) during the period of March 2014 to March 2015. The dominant source of faecal pollution in the stream was swine manure applied to the fields within the catchment. The experiments indicated that instrument pairs with the same construction design yielded highly consistent results (R 2 = 0.96 and R 2 = 0.94), whereas the results between different designs were less consistent (R 2 = 0.71). Correlations between the GLUC activity measured on-site and culture-based Escherichia coli analyses over the entire study period yielded R 2 = 0.52 and R 2 = 0.47 for the two designs, respectively. The correlations tended to be higher at the event scale. The GLUC activity was less correlated with suspended sediment concentrations than with E. coli , which is interpreted in terms of indicator applicability and the time since manure application. The study shows that this rapid assay can yield consistent results over a long period of on-site operation in technically challenging habitats. Although the use of GLUC activity as a proxy for culture-based assays could not be proven for the observed habitat, the study results suggest that this biochemical indicator has high potential for implementation in early warning systems. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine antibiotic resistance (AR) dissemination in coastal water, considering the contribution of different sources of faecal contamination. Samples were collected in Berlenga, an uninhabited island classified as Natural Reserve and visited by tourists for aquatic recreational activities. To achieve our aim, AR in Escherichia coli isolates from coastal water was compared to AR in isolates from two sources of faecal contamination: human-derived sewage and seagull faeces. Isolation of E. coli was done on Chromocult agar. Based on genetic typing 414 strains were established. Distribution of E. coli phylogenetic groups was similar among isolates of all sources. Resistances to streptomycin, tetracycline, cephalothin and amoxicillin were the most frequent. Higher rates of AR were found among seawater and faeces isolates, except for last-line antibiotics used in human medicine. Multi-resistance rates in isolates from sewage and seagull faeces (29% and 32%) were lower than in isolates from seawater (39%). Seawater AR profiles were similar to those from seagull faeces and differed significantly from sewage AR profiles. Nucleotide sequences matching resistance genes blaTEM, sul1, sul2, tet(A) and tet(B), were present in isolates of all sources. Genes conferring resistance to 3rd generation cephalosporins were detected in seawater (blaCTX-M-1 and blaSHV-12) and seagull faeces (blaCMY-2). Plasmid-mediated determinants of resistance to quinolones were found: qnrS1 in all sources and qnrB19 in seawater and seagull faeces. Our results show that seawater is a relevant reservoir of AR and that seagulls are an efficient vehicle to spread human-associated bacteria and resistance genes. The E. coli resistome recaptured from Berlenga coastal water was mainly modulated by seagulls-derived faecal pollution. The repertoire of resistance genes covers antibiotics critically important for humans, a potential risk for human health.

Laboratory-scale experiments on the survival of Escherichia coli in raw, undiluted, freshly collected, source-separated yellowwater were performed. Concentrations of E. coli and its survival at different temperature regimes and storage times were measured in yellowwater originally cross-contaminated with faeces and yellowwater purposely contaminated (deliberately spiked) with faecal material. The temperature regimes of cold (4°C), mild (10°C) and warm (22°C) were the limited factors, whereas the storage time of the contaminated yellowwater was unlimited and lasted until the E. coli concentrations reached the limit of detection of < 1 Most Probable Number (MPN)/100 mL. Temperature and pH played the main role in the inactivation and longevity of E. coli in source-separated yellowwater. The mild storage conditions were the most favourable for the persistence of E. coli, which reached 40 days with a concentration of 2.0 E+03 MPN in 100 mL of undiluted yellowwater. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine antibiotic resistance (AR) dissemination in coastal water, considering the contribution of different sources of faecal contamination. Samples were collected in Berlenga, an uninhabited island classified as Natural Reserve and visited by tourists for aquatic recreational activities. To achieve our aim, AR in Escherichia coli isolates from coastal water was compared to AR in isolates from two sources of faecal contamination: human-derived sewage and seagull faeces. Isolation of E. coli was done on Chromocult agar. Based on genetic typing 414 strains were established. Distribution of E. coli phylogenetic groups was similar among isolates of all sources. Resistances to streptomycin, tetracycline, cephalothin and amoxicillin were the most 2 frequent. Higher rates of AR were found among seawater and faeces isolates, except for last-line antibiotics used in human medicine. Multi-resistance rates in isolates from sewage and seagull faeces (29% and 32%) were lower than in isolates from seawater (39%). Seawater AR profiles were similar to those from seagull faeces and differed significantly from sewage AR profiles. Nucleotide sequences matching resistance genes blaTEM, sul1, sul2, tet(A) and tet(B), were present in isolates of all sources. Genes conferring resistance to 3rd generation cephalosporins were detected in seawater (blaCTX-M-1 and blaSHV-12) and seagull faeces (blaCMY-2). Plasmid-mediated determinants of resistance to quinolones were found: qnrS1 in all sources and qnrB19 in seawater and seagull faeces. Our results show that seawater is a relevant reservoir of AR and that seagulls are an efficient vehicle to spread human-associated bacteria and resistance genes. The E. coli resistome recaptured from Berlenga coastal water was mainly modulated by seagulls-derived faecal pollution. The repertoire of resistance genes covers antibiotics critically important for humans, a potential risk for human health. [ABSTRACT FROM AUTHOR]

We hypothesized that the transport of Escherichia coli strains harvested from springs could be characterized by a similar set of cell characteristics and transport parameters. The hypothesis was tested by sampling springs throughout the Lubigi catchment in Kampala, Uganda. Chemo-physical parameters in addition to total coliform concentrations were determined. Furthermore, E. coli strains were harvested, and cell properties determined. Column experiments in saturated quartz columns of 7 cm height were conducted to determine transport parameters of selected E. coli strains. Using a two-site non-equilibrium sorption model, transport was modelled by fitting breakthrough data in HYDRUS 1D. Results indicated faecal contamination of the springs with high concentrations of total coliforms, chloride and nitrate. Furthermore, the maximum relative E. coli concentrations (C/C0)max in the column experiments were high. Compared with our previous work on E. coli strains, collected from a pasture and from zoo animals, attachment was low. Modelling revealed that both equilibrium and kinetic sorption were not important under conditions employed in the experiments. These observations are explained by the way in which the strains were harvested: from termination points of flow lines (springs). Such strains may possess characteristics that might have influenced their transport in the subsurface leading to their low attachment efficiency and possibly contributing to the lack of influence of equilibrium and kinetic sorption characteristics. There was no significant correlation between cell properties and transport parameters. Furthermore, 58% of the tested strains were of the O21:H7 serotype, and all definable serotypes identified were associated with diseases. We speculate that this serotype may possess characteristics that allow preferential transport through the aquifers of the area. We demonstrated that bacteria harvested from termination points of flow lines compared with those obtained from pollution sources, which have not undergone transport yet, present a good option for the assessment of bacteria transport characteristics in aquifers. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The Plankenburg and Eerste Rivers (Western Cape) have been reported to be contaminated with faecal coliforms. Water is drawn from both rivers for irrigation of fresh produce. The potential risk in the use of these rivers as irrigation sources was assessed by determining the fluctuations of 'indicator' and 'index' microbes over 3 years. Selected physico-chemical (water temperature, pH, COD, conductivity and alkalinity) and microbiological parameters, including coliforms, faecal coliforms, Escherichia coli and enterococci, as 'indicators' of faecal pollution, and Salmonella, Listeria and Staphylococcus, as 'index' of the presence of potential pathogens, were monitored. No correlation was found between water temperature and COD (r2 = 0.0003), whereas for temperature and pH a significant trend (p = 0.0004), but low correlation (r2 = 0.108), was observed. With the exception of the faecal coliforms (E. coli), no significant trends and no correlations between temperature and the dependent variables were found. For the faecal coliforms there was a significant trend (p = 0.0289) with temperature but not a good correlation (r2 = 0.0434), but the impact of temperature over time was significant (p = 0.0047). This is important, when the World Health Organisation (WHO) and South African Department of Water Affairs (DWA) guidelines for faecal coliforms are applied, as it indicates that temperature does impact the faecal coliform numbers. The presence of indicator organisms did not only indicate unsanitary conditions, but also the presence of potential pathogens such as Staphylococcus, Klebsiella, Listeria and Salmonella. Based on these results the microbial quality of these rivers was found to be unacceptable and does not meet the WHO and DWA guidelines for safe irrigation. There was also a high risk of exposure to human pathogens when water from these rivers is used to irrigate produce that is consumed without further processing. [ABSTRACT FROM AUTHOR]

Abstract: Soil is known to play an important role in the cycling of the human pathogen Escherichia coli O157 in the environment. Here we investigated whether residence time in soil influenced its ability to not only survive but subsequently reactivate after release into water during a simulated rainfall event. We inoculated an agricultural soil with chromosomally lux-marked E. coli O157 and then incubated it at 4 or 15 °C for up to 120 d, at which point the pathogen was recovered by extracting the soil with rainwater and its reactivation measured by monitoring bioluminescence over a 9 h period. We found that with increasing residence time in soil, E. coli O157 exhibited a reduction in both numbers and reactivation capacity as measured by cells' energy status (bioluminescence). As the degree of cell activity is linked to infectivity, this indicates that transmissibility may be reduced after a period within soil. This should be considered when assessing the degree of risk from environmental exposure to bacterial pathogens. [Copyright &y& Elsevier]

Contamination of public water ways with sewage represents a serious environmental and health risk. We monitored pollution of the river Thames by enumerating the indicator organism Escherichia coli. Samples were taken from a site in central London near Waterloo Bridge in different seasons. E. coli were quantified using a membrane filtration method, and correlated with the tidal variations of the river and meteorological data on rainfall and temperature. More frequent and severe incidents of pollution occurred in the autumn. Heavy rainfall resulted in sharp peaks of E. coli contamination that implies a potential increase of numbers of pathogenic micro-organisms. Sixty percent of all samples were found to be in excess of the accepted upper limit of pollution set by European Union ( EU) legislation for bathing water. This study demonstrated that frequent sewage pollution of the Thames results in high numbers of E. coli and incidents of detectable levels of pathogenic bacteria demonstrating the need for regular monitoring of bacterial pollution. [ABSTRACT FROM AUTHOR]

Efficient management of deteriorating water bodies can be achieved by determining the sources of faecal pollution. Resourceful techniques for discrimination of the sources of Escherichia coli in surface water have recently been developed, including the use of river water to facilitate faecal indicator surveillance, identification of sources of faecal contamination and employing relevant management practices to maintain water quality. This study was conducted to employ microbial source tracking (MST) techniques for the determination of the sources of faecal pollution based on a water quality investigation of the physico-chemical characteristics and coliform count point of the Tirumanimuttar River. To accomplish this, an MST library-based antibiotic resistance analysis, serotyping and the genomic tool rep-PCR techniques were applied, and the obtained results were analysed statistically. Among 135 and 70 E. coli isolates present in the library and water samples collected from the river and nearby well water sources, respectively, most showed intrinsic, high or moderate resistance to antibiotics. Isolates from human and pig faecal sources were 92% homologous with the samples from the river, whereas isolates from sewage and dairy cattle showed 89% and 80% homology, respectively. These findings indicated that the Tirumanimuttar River is subjected to stress from anthropogenic activities and runoff contaminated with agricultural and human faecal contamination. The sources of faecal pollution identified in this study may facilitate the monitoring and management of the Tirumanimuttar River. [ABSTRACT FROM AUTHOR]

Abstract: Microbial source tracking is an emerging tool developed to protect water sources from faecal pollution. In this study, we evaluated the suitability of real time-quantitative PCR (qPCR) Taqman assays developed for detection of host-associated Bacteroidales markers in a prairie watershed. The qPCR primers and probes used in this study exhibited high accuracy (88–96% sensitivity and ≥99% host specificity) in detecting Bacteroidales spp. that are associated with faeces from humans, ruminants, bovines, and horses. The ruminant- and human-associated markers were also found in high concentrations within individual faecal samples, ranging from 3.4 to 7.3log10 marker copy numberg−1 of individual host faeces. Following validation of host sensitivity and specificity, the host-associated Bacteroidales markers were detected in the Qu’Appelle Valley watershed of Saskatchewan, Canada which experiences a diversity of anthropogenic inputs. Concentrations of the ruminant marker were well-correlated with proximity to cattle operations and there was a correlation between the marker and Escherichia coli concentrations at these sites. Low concentrations of the human faecal marker were measured throughout the sampling sites, and may indicate a consistent influx of human faecal pollution into the watershed area. Persistence of each of the Bacteroidales host-associated marker was also studied in situ. The results indicated that the markers persist for shorter periods of time (99% decay in <8 days) compared with the conventional E. coli marker (99% decay in >15 days), suggesting they are effective at detecting recent faecal contamination events. The levels of Bacteroidales markers and E. coli counts did not correlate with the presence of the pathogenic bacteria, Salmonella spp. or Campylobacter spp. detected in the Qu’Appelle Valley. Collectively, the results obtained in this study demonstrated that the qPCR approach for detecting host-associated Bacteroidales spp. markers can be a useful tool in helping to determine host-specific impacts of faecal pollution into a prairie watershed. [Copyright &y& Elsevier]

Multiple host-specific molecular markers were used to detect the sources of faecal pollution in a mixed land use non-sewered catchment in Southeast Queensland, Australia. These markers included human-specific Bacteroides (HF183 and HF134), cattle-specific Bacteroides (CF128), dog-specific Bacteroides (BacCan) and human-specific enterococci surface protein (esp) markers. The sensitivity and specificity of these markers were determined by testing 197 faecal samples from 13 host groups. The overall sensitivity and specificity of these markers was high (sensitivity ≥ 85% and specificity ≥ 93%) indicating their suitability for detecting the sources of faecal pollution. Of the 16 samples collected from the study area, 14 (87%) were positive for at least one of the molecular marker tested. Amongst all the markers, cattle-specific CF128 was more prevalent than others, followed by human-specific HF183 which was consistently detected in samples collected from sites within close proximity to urban development. Significant correlations were found between E. coli and enterococci concentrations with the positive/negative results of human-specific Bacteroides HF183 ( p < 0.001, p < 0.0001) and HF134 ( p < 0.001, p < 0.004) markers. No correlations were found between faecal indicators (E. coli or enterococci) with the CF128 or BacCan markers. A significant correlation was also found between enterococci concentrations and the presence/absence of the esp marker ( p < 0.02). Based on the results, it appears that the host-specific markers such as HF183 and esp are a sensitive measure of sources of human faecal pollution in surface waters in Southeast Queensland, Australia. [ABSTRACT FROM AUTHOR]

Biochemical fingerprinting (BF) databases of 524 enterococci and 571 Escherichia coli isolates and an antibiotic resistance analysis (ARA) database comprising of 380 E. coli isolates from four suspected sources (i.e. dogs, chickens, waterfowls, and human sewage) were developed to predict the sources of faecal pollution in a recreational coastal lake. Twenty water samples representing four sampling episodes were collected from five sites and the enterococci and E. coli population from each site were compared with those of the databases. The degree of similarity between bacterial populations was measured as population similarity (Sp) coefficient. Using the BF-database, bacterial populations of waterfowls showed the highest similarity with the water samples followed by a sewage treatment plant (STP). Higher population similarities were found between samples from STP and water samples especially at two sites (T2 and T3) which were located near the sewerage pipes collecting wastewater from the study area. When using the ARA-database, the highest similarity was found between E. coli populations from STP and water samples at sites T2 and T4. Both faecal indicators and as well as methods predicted human faecal pollution, possibly through leakage from submerged sewerage pipes. The results indicated that the Sp-analysis of faecal indicator bacterial populations from suspected sources and water samples can be used as a simple tool to predict the source(s) of faecal pollution in surface waters. [Copyright &y& Elsevier]

Posting or closing of swimming beaches because of faecal contamination is a widespread problem reported in many locations. In a risk-based approach to this problem, the risk to swimmers' health is assessed by field monitoring of indicator bacteria and the associated risks are managed by source controls and other remedial measures. In risk assessment, great advances have been made in recent years with the introduction of microbial source tracking (MST) techniques. Two such techniques, antibiotic resistance analysis and DNA fingerprinting, were applied in a study of causes of faecal contamination at two lake beaches in Toronto, Ontario. Both methods identified bird faeces as the dominant sources of E. coli. Coping with this type of pollution presents a major environmental challenge. [ABSTRACT FROM AUTHOR]

Library-dependent (LD) (biochemical fingerprinting of Escherichia coli and enterococci) and library-independent (LI) (PCR detection of human-specific biomarkers) methods were used to detect human faecal pollution in three non-sewered catchments. In all, 550 E. coli isolates and 700 enterococci isolates were biochemically fingerprinted from 18 water samples and compared with metabolic fingerprint libraries of 4508 E. coli and 4833 enterococci isolates. E. coli fingerprints identified human unique biochemical phenotypes (BPTs) in nine out of 18 water samples; similarly, enterococci fingerprints identified human faecal pollution in 10 water samples. Seven samples were tested by PCR for the detection of biomarkers. Human-specific HF134 Bacteroides and enterococci surface protein (esp) biomarkers were detected in five samples. Four samples were also positive for HF183 Bacteroides biomarker. The combination of biomarkers detected human faecal pollution in six out of seven water samples. Of the seven samples analysed for both the indicators/markers, at least one indicator/marker was detected in every sample. Four of the seven PCR-positive samples were also positive for one of the human-specific E. coli or enterococci BPTs. The results indicated human faecal pollution in the studied sub-catchments after storm events. LD and LI methods used in this study complimented each other and provided additional information regarding the polluting sources when one method failed to detect human faecal pollution. Therefore, it is recommended that a combination of methods should be used to identify the source(s) of faecal pollution where possible. [Copyright &y& Elsevier]

Most library-dependent bacterial source tracking studies using Escherichia coli (E. coli) have focused on strain diversity of isolates obtained from known human and animal faecal sources for library development. In contrast, this study evaluated the genotype variation of E. coli isolated from natural surface water using pulsed field gel electrophoresis (PFGE) and enterobacterial repetitive intergenic consensus sequence polymerase chain reaction (ERIC-PCR) to better understand these naturally occurring populations. A total of 650 water samples were collected over a nine month period from eleven sampling stations from Lake Waco and Belton Lake in Central Texas. Of the 650 water samples collected, 412 were positive for E. coli, yielding a total of 631 E. coli isolates (1–12 isolates collected per sample). PFGE and ERIC-PCR patterns were successfully generated for 555 isolates and were compared using the curve-based Pearson''s product–moment correlation coefficient. The 555 E. coli isolates represented 461 PFGE genotypes, with 84% (386/461) of the genotypes being represented by individual isolates. The remaining 75 genotypes were represented by 2–5 isolates each. Using ERIC-PCR, the 555 E. coli isolates represented 175 genotypes, with 63% (109/175) of the genotypes being represented by individual isolates. In contrast to the PFGE results, two ERIC-PCR genotypes represented 37% of the E. coli isolates, (83 and 124 isolates, respectively), and were found throughout the watersheds both spatially and temporally. Based on the PFGE genotype diversity of water isolates, there is little evidence that a small number of environmentally-adapted E. coli represent dominant populations in the studied waterbodies. However, with the lower discriminatory power technique ERIC-PCR, an opposing conclusion might have been drawn. These results emphasize the importance of considering the resolving power of the source tracking technique being used when assessing strain diversity and geographical stability. [Copyright &y& Elsevier]

Aims: The Escherichia coli burden at a Great Lakes urban beach was evaluated during the summer months to determine if sand served as a reservoir for E. coli, and if there was evidence of cell replication in situ. Field and laboratory studies investigated the effects of moisture, temperature and UV on E. coli densities in the sand. Methods and Results: Sand samples ( n = 481) were collected across three distinct transects of the beach, the top, a middle streamline, and the berm, over 15 sample days. The highest levels were found in the middle streamline, which was affected by stormwater discharge from nearby outfalls and roosting gulls; daily geometric mean levels of these seven sites ranged from 6700 to 40 900 CFU per 100 g of sand. Escherichia coli levels were greatest in samples with moisture levels between 15% and 19%, and were significantly higher than 0–4 and 20–24% ranges ( P < 0·05). Pre- and post-rain samples at the beach demonstrated an increase in E. coli levels nearly 100-fold within 30 min, suggesting sand washout as a major mechanism for loading of E. coli into the beach waters. Rep PCR analysis of 160 isolates obtained from eight sites demonstrated that 21% of the isolates fell into one of the six clonal patterns, suggesting that bacteria may be able to replicate and possibly colonize beach sand. Sand field plots inoculated with E. coli cells containing pGFPuv that expresses GFP (green fluorescent protein) as a marker showed an initial two- to 100-fold increase at 24 h, depending on the temperature condition. The sand appeared to provide considerable protection from UV exposure as no significant difference was seen in cell densities within the first 2–4 cm of sand between exposed and unexposed plots ( P < 0·05). Conclusions: Beach sand may act as a reservoir for E. coli. Replication of cells appears to be one possible contributing factor to the persistently high levels, as indicated by both field studies and laboratory studies, and warrants further investigation. Moisture content of sand may also be a determinant of cell persistence in the sand environment. Significance and Impact of the Study: Escherichia coli is used as an indicator organism for faecal pollution at most Great Lakes coastal beaches; therefore, a better understanding of how E. coli might survive, or possibly replicate, in the environment would improve interpretation of beach monitoring results. [ABSTRACT FROM AUTHOR]

Current measures for controlling the public health risks associated with bivalve molluscan shellfish consumption rely on the use of Escherichia coli to indicate the sanitary quality of shellfish harvesting areas. However, it has been demonstrated that E. coli is an inadequate indicator of the viral risk associated with shellfish. An alternative indicator, male-specific B+ coliphages, have been investigated as viral indicators of faecal contamination that may provide source-specific information for impacted environmental waters. This study compared the distribution of E. coli and F+ RNA bacteriophages in shellfish grown in harvesting areas of Greece and also examined the presence and proportions of the different subgroups of F+ RNA coliphages in shellfish. F+ RNA bacteriophages were present in shellfish at higher concentrations than E. coli. Elevated numbers of F+ RNA bacteriophages observed in the winter concur with the known increased viral risk associated with shellfish harvested at that time of year in Greece. The majority of F+ RNA coliphages detected in shellfish samples belonged to group IV which indicated the possible presence of animal faecal material in sample harvesting areas. Phages of groups II and III (human waste and human faecal material, respectively) were present at low levels. Finally, 8% of the phages hybridised were found to belong to group I. The presence of group IV showed seasonal distribution (more in winter, less in summer) whereas the other groups did not show any difference. Monitoring of F+ coliphage subgroups may indicate the presence and major sources of microbial inputs to surface waters; however, environmental effects on the relative occurrence of different groups need to be considered. [ABSTRACT FROM AUTHOR]

A faecal pollution monitoring of coastal Messina waters was performed by comparing three (microscopic, enzyme, and culture) methods. Evidence of Escherichia coli cells (29.99 to 96.79% of the total enteropathogenic serotypes) retaining their viability into the marine environment was shown. β‐Glucuronidase activity rates suggested that living cells were also metabolically active. Heavily polluted sites were detected, where improperly treated urban wastes were discharged. Significant relationships between microscopic and enzymatic data proved both methods to be suitable alternatives to the culture method for E. coli detection, improving environmental quality assessment. [ABSTRACT FROM AUTHOR]

Untreated sewage has been released from Port-aux Franc¸ais station, Kerguelen Island, into the Southern Ocean for more than 50 years. We investigated the spatial distribution of faecal bacteria indicators during a one-year survey conducted in seawater off Morbihan Bay near the French permanent station of the Kerguelen Island (49°21′S, 70°30′E). Seawater samples were taken bimonthly from nine stations evenly distributed around the sewage outfalls of the station. Escherichia coli and enterococci were estimated using specific microplates (Miniaturized method for the enumeration of E. coli or enterococci in surface and waste waters, “MU/EC or MU/SF methods”, BIO-RAD©). In order to evaluate the role of seasonal changes of environmental parameters on the survival of enteric bacteria, total and saprophytic bacterial abundances were also estimated in all seawater samples. High densities of faecal bacteria (maximum 104 cells 100 ml−1) were found in seawater surrounding the sewage outfall. However, enteric bacterial counts decreased rapidly with increasing distance from the outfall. In all samples collected further than 2 km from the outfall, the bacterial indicators were absent or present in small numbers (<10 cells 100 ml−1). Faecal coliforms were not detected in samples collected at pristine sites located 10 km from Port-aux-Franc¸ais. Despite these low contamination levels, faecal bacteria were always detected in the vicinity of the sewage outfall during the seasonal survey. The concentration of faecal bacteria may be related to the number of people inhabiting the station. [Copyright &y& Elsevier]

The aim of this study is to develop a relocatable modelling system able to describe the microbial contamination that affects the quality of coastal bathing waters. Pollution events are mainly triggered by urban sewer outflows during massive rainy events, with relevant negative consequences on the marine environment and tourism and related activities of coastal towns. A finite element hydrodynamic model was applied to five study areas in the Adriatic Sea, which differ for urban, oceanographic and morphological conditions. With the help of transport-diffusion and microbial decay modules, the distribution of Escherichia coli was investigated during significant events. The numerical investigation was supported by detailed in situ observational datasets. The model results were evaluated against water level, sea temperature, salinity and E. coli concentrations acquired in situ, demonstrating the capacity of the modelling suite in simulating the circulation in the coastal areas of the Adriatic Sea, as well as several main transport and diffusion dynamics, such as riverine and polluted waters dispersion. Moreover, the results of the simulations were used to perform a comparative analysis among the different study sites, demonstrating that dilution and mixing, mostly induced by the tidal action, had a stronger effect on bacteria reduction with respect to microbial decay. Stratification and estuarine dynamics also play an important role in governing microbial concentration. The modelling suite can be used as a beach management tool for improving protection of public health, as required by the EU Bathing Water Directive. [ABSTRACT FROM AUTHOR]