Indicators Of Fecal Contamination Research Articles

Capsid Integrity Detection of Enteric Viruses in Reclaimed Waters

Climate change, unpredictable weather patterns, and droughts are depleting water resources in some parts of the globe, where recycling and reusing wastewater is a strategy for different purposes. To counteract this, the EU regulation for water reuse sets minimum requirements for the use of reclaimed water for agricultural irrigation, including a reduction in human enteric viruses. In the present study, the occurrence of several human enteric viruses, including the human norovirus genogroup I (HuNoV GI), HuNoV GII, and rotavirus (RV), along with viral fecal contamination indicator crAssphage was monitored by using (RT)-qPCR methods on influent wastewater and reclaimed water samples. Moreover, the level of somatic coliphages was also determined as a culturable viral indicator. To assess the potential viral infectivity, an optimization of a capsid integrity PMAxx-RT-qPCR method was performed on sewage samples. Somatic coliphages were present in 60% of the reclaimed water samples, indicating inefficient virus inactivation. Following PMAxx-RT-qPCR optimization, 66% of the samples tested positive for at least one of the analyzed enteric viruses, with concentrations ranging from 2.79 to 7.30 Log10 genome copies (gc)/L. Overall, most of the analyzed reclaimed water samples did not comply with current EU legislation and contained potential infectious viral particles.

Multivariate statistical methods for analysis of physicochemical and microbiological parameters of well water from the village M’Pody

The pollution of surface water and groundwater is a real public health problem that is currently receiving particular attention throughout the world. The use of water for food or hygiene purposes requires excellent physicochemical and microbiological quality. Well water is used for many purposes by the inhabitants of M’pody, a village in the Anyama district of Côte d’Ivoire. In this village, an epidemic of diarrhoea was detected in January 2020. This epidemic claimed sixty-nine (69) victims. This study aims to evaluate well water quality controls using the methods of principal component analysis (PCA), correspondence factorial analysis (CFA), analysis of variance (ANOVA) and self-organizing map (SOM) algorithm. The parameters studied were, turbidity (Tur), conductivity (Cond), hydrogen potential (pH), temperature (T), nitrate (NO3-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$NO_{3^{-}}$$\\end{document}), nitrite (NO2-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$NO_{2^{-}}$$\\end{document}), ammonium (NH4+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$NH_{4^{+}}$$\\end{document}), phosphates (PO43-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$PO_{4}^{3^{-}}$$\\end{document}), chlorides (Cl-)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$(Cl^{-})$$\\end{document}, total hydrotimetric degree (DHT), sulfates (SO42-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$SO_{4}^{2^{-}}$$\\end{document}), bicarbonate (HCO3-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$HCO_{3^{-}}$$\\end{document}), total alkalinity contents (TAC), escherichia coli (E.coli), thermotolerant coliforms (CTH) and enterococcus faecalis (E.faecalis). Data were collected from seventy-two (72) wells in the village during four campaigns in 2020. Physicochemical parameters were determined by electrochemical and spectrophotometric methods. Microbiological analysis was carried out using membrane filtration technique. Descriptive statistics revealed that Tur, Cond, pH and T parameters did not meet world health organization (WHO, 2017) standards. However, the parameters NO3-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$NO_{3^{-}}$$\\end{document}, NO2-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$NO_{2^{-}}$$\\end{document}, NH4+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$NH_{4^{+}}$$\\end{document}, PO43-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$PO_{4}^{3^{-}}$$\\end{document}, Cl-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$Cl^{-}$$\\end{document}, DHT, TAC, SO42-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$SO_{4}^{2^{-}}$$\\end{document} and HCO3-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$HCO_{3^{-}}$$\\end{document} comply with WHO standards. The results of bacteriological analyzes confirm the presence in very significant numbers of indicators of faecal contamination (CTH, E.coli and E.faecalis) in all wells. The logical explanations for faecal pollution would come from the infiltration of septic tanks located near the wells and the run-off of waste water carrying human and animal faecal matter. The diarrhea epidemic would therefore be caused by the consumption of this polluted water. PCA, FCA and hierarchical cluster analysis (HCA) were jointly employed to identify the structure of wells and deduce the principal factors controlling the parameters of these well waters. ANOVA revealed the effect of human-induced activities as the main factors influencing the physicochemical and microbiological parameters of the studied well waters. Further studies should focus on multivariate statistical techniques for effective forecasting and monitoring of emerging pollution for improved water quality.

Relationship between nitrate, heavy metal, and sterols contents in Japanese agricultural soils with risk of groundwater pollution

In Japanese agricultural lands, nitrate-nitrogen contamination of soil and groundwater often occurs due to the application of livestock excrements and compost. Therefore, rural soils in Japan were sampled and analyzed for nitrate-nitrogen leaching, heavy metal content, and sterols associated with livestock excrement and compost to calculate contamination risk indicators. The results were analyzed using self-organizing maps and cluster analysis. Nitrate-nitrogen content using water extraction was detected in most of the sampled soils. In addition, many samples from areas that were already severely contaminated with nitrate-nitrogen showed particularly high concentrations. Coprostanol, an indicator of fecal contamination, was detected in more than half of the samples. The main source of nitrate-nitrogen contamination in these areas is livestock excrement and compost. Self-organization maps showed that areas with high nitrate-nitrogen contamination also corresponded to areas with high copper and zinc soil contents. The self-organization maps and cluster analysis resulted in five clusters: a nitrate-contaminated group mainly originating from livestock excrement and compost, a heavy metal-contaminated group, a general group, a nitrate-contaminated group mainly originating from chemical fertilizers, and a contaminated group with potentially hazardous substances requiring attention. Authorities and decision-makers can use the results to prioritize areas requiring remediation.

Utilizing novel Escherichia coli-specific conserved signature proteins for enhanced monitoring of recreational water quality.

Escherichia coli serves as a proxy indicator of fecal contamination in aquatic ecosystems. However, its identification using traditional culturing methods can take up to 24h. The application of DNA markers, such as conserved signature proteins (CSPs) genes (unique to all species/strains of a specific taxon), can form the foundation for novel polymerase chain reaction (PCR) tests that unambiguously identify and detect targeted bacterial taxa of interest. This paper reports the identification of three new highly-conserved CSPs (genes), namely YahL, YdjO, and YjfZ, which are exclusive to E. coli/Shigella. Using PCR primers based on highly conserved regions within these CSPs, we have developedquantitative PCR (qPCR) assays for the evaluation of E. coli/Shigella species in water ecosystems. Both in-silico and experimental PCR testing confirmed the absence of sequence match when tested against other bacteria, thereby confirming 100% specificity of the tested CSPs for E. coli/Shigella. The qPCR assays for each of the three CSPs provided reliable quantification for all tested enterohaemorrhagic and environmental E. coli strains, a requirement for water testing. For recreational water samples, CSP-based quantification showed a high correlation (r > 7, p < 0.01) with conventional viable E. coli enumeration. This indicates that novel CSP-based qPCR assays for E. coli can serve as robust tools for monitoring water ecosystems and other critical areas, including food monitoring.

Impact of operational conditions on drinking water biofilm dynamics and coliform invasion potential.

The revelation that even low concentrations of coliforms can infiltrate into mature drinking water biofilms highlights a potential public health concern. Nowadays, the measurement of coliform bacteria is used as an indicator for fecal contamination and to control the effectiveness of disinfection processes and the cleanliness and integrity of distribution systems. In Flanders (Belgium), 533 out of 18,840 measurements exceeded the established norm for the coliform indicator parameter in 2021; however, the source of microbial contamination is mostly unknown. Here, we showed that mature biofilms, are susceptible to invasion of Serratia fonticola. These findings emphasize the importance of understanding and managing biofilms in drinking water distribution systems, not only for their potential to influence water quality, but also for their role in harboring and potentially disseminating pathogens. Further research into biofilm detachment, long-term responses to operational changes, and pathogen persistence within biofilms is crucial to inform strategies for safeguarding drinking water quality.

Comparison of methods proposed for monitoring cefotaxime-resistant Escherichia coli in the water environment.

Escherichia coli is a promising subject for globally coordinated surveillance of antimicrobial resistance (AMR) in water environments due to its clinical relevance and widespread use as an indicator of fecal contamination. Cefotaxime-resistant E. coli was recently evaluated favorably for this purpose by the World Health Organization TriCycle Protocol, which specifies tryptone bile x-glucuronide (TBX) medium and incubation at 35°C. We assessed comparability with the U.S. Environmental Protection Agency-approved method for E. coli quantification, which uses membrane-thermotolerant E. coli (mTEC) agar and incubation at 44.5°C, in terms of recovery of E. coli and cefotaxime-resistant E. coli from wastewater influent and surface waters. Total E. coli concentrations in wastewater influent were 106-108 CFU/100 mL, while cefotaxime-resistant E. coli were ~100-fold lower. Total E. coli in surface waters were ~102 CFU/100 mL, and cefotaxime-resistant isolates were near the limit of detection (0.4 CFU/100 mL). Total and putative cefotaxime-resistant E. coli concentrations did not differ significantly between media or by incubation method; however, colonies isolated on mTEC were more frequently confirmed to species (97.1%) compared to those from TBX (92.5%). Incubation in a water bath at 44.5°C significantly decreased non-specific background growth and improved confirmation frequency on both media (97.4%) compared to incubation at 35°C (92.3%). This study helps to advance globally coordinated AMR in water environments and suggests that the TriCycle Protocol is adaptable to other standard methods that may be required in different locales, while also offering a means to improve specificity by decreasing the frequency of false-positive identification of cefotaxime-resistant E. coli by modifying incubation conditions.IMPORTANCEAs antibiotic-resistant bacteria in water environments are increasingly recognized as contributors to the global antibiotic resistance crisis, the need for a monitoring subject that captures antibiotic resistance trends on a global scale increases. The World Health Organization TriCycle Protocol proposes the use of cefotaxime-resistant Escherichia coli isolated on tryptone bile x-glucuronide agar. The U.S. Environmental Protection Agency (USEPA) criteria for safe recreational waters also use E. coli as an indicator but specify the use of mTEC agar at a higher incubation temperature (44.5°C vs 35°C). We assessed the comparability of these methods for isolating total and cefotaxime-resistant E. coli, finding overall good agreement and performance, but significantly higher specificity toward E. coli selection with the use of the USEPA incubation protocol and mTEC agar. This study is the first to directly compare these methods and provides evidence that the methods may be used interchangeably for global surveillance of antibiotic resistance in the environment.

Evaluation of crAssphages as a potential marker of human viral contamination in environmental water and fresh leafy greens.

CrAssphages are human gut bacteriophages with potential use as an indicator of human fecal contamination in water and other environmental systems. We determined the prevalence and abundance of crAssphages in water, food, and fecal samples and compared these estimates with the prevalence of norovirus. Samples were tested using two crAssphage-specific qPCR assays (CPQ056 and TN201-203) and for norovirus using TaqMan realtime RT-PCR. CrAssphage was detected in 40% of human fecal specimens, 61% of irrigation water samples, 58.5% of stream water samples, and 68.5% of fresh leafy greens samples. Interestingly, across all sample categories, crAssphage concentrations were 2-3 log10 higher than norovirus concentrations. The correlation of detection of crAssphage and norovirus was significant for the irrigation water samples (r = 0.74, p = 7.4e-06). Sequences obtained from crAssphage positive samples from human fecal and stream water samples phylogenetically clustered with genotype I crAssphages, whereas sequences derived from irrigation water samples clustered differently from other genotypes. Our data show that crAssphages were prevalent in norovirus-positive water samples and in fresh leafy green samples, there was a strong correlation between the presence of crAssphage and norovirus. CrAssphage genomic copies were consistently higher than norovirus copies in all sample types. Overall, our findings suggest that crAssphages could be used as reliable indicators to monitor fecal-borne virus contamination within the food safety chain.

Private and well drinking water are reservoirs for antimicrobial resistant bacteria

Water quality testing does not recognise antimicrobial resistance (AMR) and is often limited to indicators of faecal contamination Escherichia coli and Enterococcus species. In Europe, data on AMR in drinking water is scarce. In Ireland, as in many countries, household drinking water is supplied via mains or via private wells or water schemes. Using citizen science, we identified Irish private drinking water supplies as reservoirs of antimicrobial resistant bacteria (ARB). Gram-negative (n = 464) and Gram-positive (n = 72) bacteria were isolated. We identified instances of potentially opportunistic ARB such as Enterobacter cloacae, Acinetobacter baumannii and Enterococcus species. We report reservoirs of multidrug resistance in Enterococcus casseliflavus, E. cloacae, E. coli, Stenotrophomonas maltophilia, and Serratia rubidaea. We also identified linezolid-resistant Enterococcus in Irish drinking water. Linezolid is a last-resort antibiotic used to treat vancomycin-resistant Enterococcus sp. Additionally, we identified mobile AMR in three water samples, two of which were carried on IncF group, one on IncQ and five on Col-like plasmids. Our work suggests that private drinking water is a potential sink and source of AMR pathogens. This highlights a value of drinking water surveillance in a One Health framework as the surveillance would provide information regarding the movement and persistence of ARB and ARGs that are able to survive in drinking water and subsequently have the opportunity to be mobilised through humans; linking the environment to the human and potentially threatening human health.

Urban wastewater-based epidemiology for multi-viral pathogen surveillance in the Valencian region, Spain

Wastewater-based epidemiology (WBE) has lately arised as a promising tool for monitoring and tracking viral pathogens in communities. In this study, we analysed WBE's role as a multi-pathogen surveillance strategy to detect the presence of several viral illness causative agents. Thus, an epidemiological study was conducted from October 2021 to February 2023 to estimate the weekly levels of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), Respiratory Syncytial virus (RSV), and Influenza A virus (IAV) in influent wastewater samples (n = 69). In parallel, a one-year study (October 2021 to October 2022) was performed to assess the presence of pathogenic human enteric viruses. Besides, monitoring of proposed viral fecal contamination indicators crAssphage and Pepper mild mottle virus (PMMoV) was also assessed, along with plaque counting of somatic coliphages. Genetic material of rotavirus (RV), human astrovirus (HAStV), and norovirus genogroup I (GI) and GII was found in almost all samples, while hepatitis A and E viruses (HAV and HEV) only tested positive in 3.77 % and 22.64 % of the samples, respectively. No seasonal patterns were overall found for enteric viruses, although RVs had a peak prevalence in the winter months. All samples tested positive for SARS-CoV-2 RNA, with a mean concentration of 5.43 log genome copies per liter (log GC/L). The tracking of the circulating SARS-CoV-2 variants of concern (VOCs) was performed by both duplex RT-qPCR and next generation sequencing (NGS). Both techniques reliably showed how the dominant VOC transitioned from Delta to Omicron during two weeks in Spain in December 2021. RSV and IAV viruses peaked in winter months with mean concentrations 6.40 and 4.10 log GC/L, respectively. Moreover, the three selected respiratory viruses strongly correlated with reported clinical data when normalised by wastewater physico-chemical parameters and presented weaker correlations when normalising sewage concentration levels with crAssphage or somatic coliphages titers. Finally, predictive models were generated for each respiratory virus, confirming high reliability on WBE data as an early-warning system and communities illness monitoring system. Overall, this study presents WBE as an optimal tool for multi-pathogen tracking reflecting viral circulation and diseases trends within a selected area, its value as a multi-pathogen early-warning tool stands out due to its public health interest.

Genome mining of Escherichia coli WG5D from drinking water source: unraveling antibiotic resistance genes, virulence factors, and pathogenicity

BackgroundEscherichia coli, a ubiquitous inhabitant of the gut microbiota, has been recognized as an indicator of fecal contamination and a potential reservoir for antibiotic resistance genes. Its prevalence in drinking water sources raises concerns about the potential dissemination of antibiotic resistance within aquatic ecosystems and the subsequent impact on public health. The ability of E. coli to acquire and transfer resistance genes, coupled with the constant exposure to low levels of antibiotics in the environment, underscores the need for comprehensive surveillance and rigorous antimicrobial stewardship strategies to safeguard the quality and safety of drinking water supplies, ultimately mitigating the escalation of antibiotic resistance and its implications for human well-being.MethodsWG5D strain, isolated from a drinking water distribution source in North-West Province, South Africa, underwent genomic analysis following isolation on nutrient agar, anaerobic cultivation, and DNA extraction. Paired-end Illumina sequencing with a Nextera XT Library Preparation kit was performed. The assembly, annotation, and subsequent genomic analyses, including phylogenetic analysis using TYGS, pairwise comparisons, and determination of genes related to antimicrobial resistance and virulence, were carried out following standard protocols and tools, ensuring comprehensive insights into the strain’s genomic features.ResultsThis study explores the notable characteristics of E. coli strain WG5D. This strain stands out because it possesses multiple antibiotic resistance genes, encompassing tetracycline, cephalosporin, vancomycin, and aminoglycoside resistances. Additionally, virulence-associated genes indicate potential heightened pathogenicity, complemented by the identification of mobile genetic elements that underscore its adaptability. The intriguing possibility of bacteriophage involvement and factors contributing to pathogenicity further enriches our understanding. We identified E. coli WG5D as a potential human pathogen associated with a drinking water source in South Africa. The analysis provided several antibiotic resistance-associated genes/mutations and mobile genetic elements. It further identified WG5D as a potential human pathogen. The occurrence of E. coli WG5D raised the awareness of the potential pathogens and the carrying of antibiotic resistance in drinking water.ConclusionsThe findings of this study have highlighted the advantages of the genomic approach in identifying the bacterial species and antibiotic resistance genes of E. coli and its potential as a human pathogen.

Investigation of Salmonella, hepatitis E virus (HEV) and viral indicators of fecal contamination in four Italian pig slaughterhouses, 2021–2022

In the pork production chain, the control at slaughterhouse aims to ensure safe food thanks to proper hygienic conditions during all steps of the slaughtering. Salmonella is one of the main foodborne pathogens in the EU causing a great number of human cases, and pigs also contribute to its spreading. Pig is the main reservoir of the zoonotic hepatitis E virus (HEV) that can be present in liver, bile, feces and even rarely in blood and muscle. The aim of this study was to assess the presence of both Salmonella and HEV in several points of the slaughtering chain, including pig trucks. Other viruses hosted in the gut flora of pigs and shed in feces were also assayed (porcine adenovirus PAdV, rotavirus, norovirus, and mammalian orthoreovirus MRV). Torque teno sus virus (TTSuV) present in both feces, liver and blood was also considered. Four Italian pig abattoirs were sampled in 12 critical points, 5 of which were the outer surface of carcasses before processing. HEV and rotavirus (RVA) were not detected. Norovirus was detected once. Salmonella was detected in two of the 4 abattoirs: in the two lairage pens, in the site of evisceration and on one carcass, indicating the presence of Salmonella if carcass is improper handled. The sampling sites positive for Salmonella were also positive for PAdV. MRV was detected in 10 swabs, from only two abattoirs, mainly in outer surface of carcasses. TTSuV was also detected in all abattoirs. Our study has revealed a diverse group of viruses, each serving as indicator of either fecal (NoV, RVA, PAdV, MRV) or blood contamination (TTSuV). TTSuV could be relevant as blood contamination indicators, crucial for viruses with a viremic stage, such as HEV. The simultaneous presence of PAdV with Salmonella is relevant, suggesting PAdV as a promising indicator for fecal contamination for both bacterial and viruses. In conclusion, even in the absence of HEV, the widespread presence of Salmonella at various points in the chain, underscores the need for vigilant monitoring and mitigation strategies which could be achieved by testing not only bacteria indicators as expected by current regulation, but also some viruses (PAdV, TTSuV, MRV) which could represent other sources of fecal contamination.

Tracking enteric pathogen contamination from on-site sanitation facilities to groundwater in selected rural areas of Vhembe District Municipality, Limpopo Province, South Africa

Groundwater is valued as a source of potable water, although it is vulnerable to environmental pollution. The aim of this study was to track enteric pathogen contamination from on-site sanitation (OSS) facilities to 70 household boreholes used by four villages of the Vhembe District Municipality. Two objectives were pursued: to measure the lateral distance between the borehole and the sanitation facilities in household yards, and to track the enteric pathogens. The borehole abstraction point and OSS system distance were determined using a steel measuring tape. Real-time PCR was used to track Shigella flexneri, Salmonella typhimurium, Campylobacter jejuni, and enterotoxigenic Escherichia coli (ETEC) from Wastewater (WW) from domestic septic tank and sludge from pit latrines to boreholes. Escherichia coli was used as an indicator of faecal contamination. Results showed that 25% of households kept a distance of ≥50 m between the OSS facilities and the boreholes. In total, 87.5% of household boreholes in the rainy season and 72.5% in the dry season were contaminated with E. coli and pathogenic bacteria: Shigella flexneri, Salmonella typhimurium, and ETEC. The concentrations of the pathogens ranged from 2.03 to 2.12 LogEGC/100 mL. A very weak (r = −0.093) to moderate (r = −0.541) association was found between pathogens in groundwater and on-site sanitation systems (WW from septic tank and sludge from pit latrine). This suggests that the pathogens were not present in the sanitation compartment when they were found in the groundwater and vice versa. Moreover, a very weak (r = 0.007) to moderate (r = 0.525) association was found between the detected contaminants in groundwater and the lateral distance between the OSS facilities and the boreholes. The pathogens detected in all samples showed consistent concentrations, suggesting potential contamination from OSS systems' waste, possibly in groundwater, indicating potential contamination. The siting of OSS facilities at the yards in this study appeared to have a slight influence on the contaminants detected in groundwater. This study calls for an education program to be implemented by the Water and Sanitation Services Authorities to prevent contamination of groundwater and the risk of waterborne diseases.

A Unique Monitoring Method for Fecal and Sewage-Derived Chemical Pollution Utilizing International Pellet Watch Approach.

This study established a unique approach to assess fecal contamination by measuring fecal sterols, especially coprostanol (5β-cholestanol-3β-ol, 5β) and cholestanol (5α-cholestan-3β-ol, 5α) and their ratio 5β/(5β + 5α) alongside triclosan (TCS) and methyl-triclosan (MTC) in beached plastic pellets across 40 countries. Coprostanol concentrations ranged from 3.6 to 8190 ng/g pellet with extremely high levels in densely populated areas in African countries. The 5β/(5β + 5α) ratio was not affected by the difference in residence time of pellets in aquatic environments, and their spatial pattern showed a positive correlation with that of sedimentary sterols, demonstrating its reliability as an indicator of fecal contamination. Pellets from populated areas of economically developing countries, i.e., Africa and Asia, with lower coverage of wastewater treatment exhibited higher 5β/(5β + 5α) ratios (∼0.7) corresponding to ∼1% sewage in seawater, while pellets from developed countries, i.e., the USA, Canada, Japan, and Europe, with higher coverage of modern wastewater treatment displayed lower ratios (∼0.5), corresponding to the first contact limit. Triclosan levels were higher in developing countries (0.4-1298 ng/g pellet), whereas developed countries showed higher methyl-triclosan levels (0.5-70 ng/g pellet) due to TCS conversion during secondary treatment. However, some samples from Japan and Europe displayed higher TCS levels, suggesting contributions from combined sewage overflow (CSO). Combination of 5β/(5β + 5α) and MTC/TCS ratios revealed extreme fecal contamination from direct input of raw sewage due to inadequate treatment facilities in some African and South and Southeast Asian countries.

Faecal contamination on lettuce irrigated with different water sources in Maputo, Mozambique

ABSTRACT Faecal contamination across the lettuce value chain was assessed in Maputo, Mozambique. Escherichia coli was used as an indicator of faecal contamination, with concentrations ranging from 3.4 to 5.7 log units/100 ml in groundwater, river water and partially treated wastewater. Municipal tap water used to wash lettuce heads in the markets had lower than 1 log unit/100 ml. Irrespective of the source of irrigation water, the lettuce heads were contaminated throughout the value chain, with concentrations ranging between 6.5 and 7.8 log units/100 g. Interventions and awareness raising should be applied at every stage of the value chain.

Suboptimal Bacteriological Quality of Household Water in Municipal Ibadan, Nigeria.

Access to potable water is difficult for many African residents. This study evaluated the bacteriological quality of household water collected in the dry and wet seasons across five municipal local government areas (LGAs) in Ibadan, a large city in southwest Nigeria. A total of 447 water samples (dry season, n = 250; wet season, n = 197) were aseptically collected from a random sample of mapped households within Ibadan's five municipal LGAs. The pH values and total aerobic and coliform bacterial counts were measured, and samples were screened for Escherichia coli, Salmonella, Shigella, and Yersinia by standard phenotypic techniques and multiplex polymerase chain reaction. The most common source of water was well (53.2%), followed by borehole (34%). None of the households used municipal tap water. Cumulatively, aerobic (P = 0.0002) and coliform (P = 0.0001) counts as well as pH values (P = 0.0002) changed significantly between seasons, with increasing and decreasing counts depending on the LGA. Nonpotable water samples were found to be very common during the dry (86.8%) and wet (74.1%) seasons. Escherichia coli spp., as indicators of recent fecal contamination, were isolated from 115 (25.7%) of the household water sources. Thirty three Salmonella, four enteroaggregative E. coli, and four enterotoxigenic E. coli isolates but no Shigella or Yersinia isolates were identified. This study revealed the absence of treated tap water and the poor quality of alternative sources with detectable pathogens in municipal Ibadan. Addressing the city-wide lack of access to potable water is an essential priority for preventing a high prevalence of feco-orally transmitted infections.

High-resolution genomic analysis to investigate the impact of the invasive brushtail possum (Trichosurus vulpecula) and other wildlife on microbial water quality assessments.

Escherichia coli are routine indicators of fecal contamination in water quality assessments. Contrary to livestock and human activities, brushtail possums (Trichosurus vulpecula), common invasive marsupials in Aotearoa/New Zealand, have not been thoroughly studied as a source of fecal contamination in freshwater. To investigate their potential role, Escherichia spp. isolates (n = 420) were recovered from possum gut contents and feces and were compared to those from water, soil, sediment, and periphyton samples, and from birds and other introduced mammals collected within the Mākirikiri Reserve, Dannevirke. Isolates were characterized using E. coli-specific real-time PCR targeting the uidA gene, Sanger sequencing of a partial gnd PCR product to generate a gnd sequence type (gST), and for 101 isolates, whole genome sequencing. Escherichia populations from 106 animal and environmental sample enrichments were analyzed using gnd metabarcoding. The alpha diversity of Escherichia gSTs was significantly lower in possums and animals compared with aquatic environmental samples, and some gSTs were shared between sample types, e.g., gST535 (in 85% of samples) and gST258 (71%). Forty percent of isolates gnd-typed and 75% of reads obtained by metabarcoding had gSTs shared between possums, other animals, and the environment. Core-genome single nucleotide polymorphism (SNP) analysis showed limited variation between several animal and environmental isolates (<10 SNPs). Our data show at an unprecedented scale that Escherichia clones are shared between possums, other wildlife, water, and the wider environment. These findings support the potential role of possums as contributors to fecal contamination in Aotearoa/New Zealand freshwater. Our study deepens the current knowledge of Escherichia populations in under-sampled wildlife. It presents a successful application of high-resolution genomic methods for fecal source tracking, thereby broadening the analytical toolbox available to water quality managers. Phylogenetic analysis of isolates and profiling of Escherichia populations provided useful information on the source(s) of fecal contamination and suggest that comprehensive invasive species management strategies may assist in restoring not only ecosystem health but also water health where microbial water quality is compromised.

Microbiological hazard identification in river waters used for recreational activities

Pathogenic bacteria, viruses, and parasites can cause waterborne disease outbreaks. The study of coastal water quality contributes to identifying potential risks to human health and to improving water management practices. The Río de la Plata River, a wide estuary in South America, is used for recreational activities, as a water source for consumption and as a site for sewage discharges. In the present study, as the first step of a quantitative microbial risk assessment of the coastal water quality of this river, a descriptive study was performed to identify the microbial pathogens prevalent in its waters and in the sewage discharged into the river. Two sites, representing two different potential risk scenarios, were chosen: a heavily polluted beach and an apparently safe beach. Conductivity and fecal contamination indicators including enterococci, Escherichia coli, F + RNA bacteriophages, and human polyomaviruses showed high levels. Regarding enterococci, differences between sites were significant (p-values <0.001). 93.3% and 56.5% of the apparently safe beach exceeded the recreational water limits for E. coli and enterococci. Regarding pathogens, diarrheagenic E. coli, Salmonella, and noroviruses were detected with different frequencies between sites. The parasites Cryptosporidium spp. and Giardia duodenalis were frequently detected in both sites. The results regarding viral, bacterial, and parasitic pathogens, even without correlation with conventional indicators, showed the importance of monitoring a variety of microorganisms to determine water quality more reliably and accurately, and to facilitate further studies of health risk assessment. The taxonomic description of microbial pathogens in river waters allow identifying the microorganisms that infect the population living on its shores but also pathogens not previously reported by the clinical surveillance system.

Bioaerosols in Eastern Canadian Dairy Barns Using Tie- and Free-Stall Housing

Highlights Building characteristics (ventilation and animal density) seem to have an important effect on air quality. Concentration in the air seems to be influenced by amounts in the bedding for certain air quality indicators. Dust concentrations were below OSHA threshold, while some barns exceeded DECOS threshold for endotoxins. This study gives new data into the biological components in the air of dairy barns (bacteria, molds, endotoxins, etc.) Free-stall or tie-stall housing may not be linked with poorer air quality. Abstract. Alternative farming methods make it possible to satisfy public demands for animal welfare while preserving production efficiency, with free housing in dairy farms being an example. The increased movement of cows may have a negative impact on air quality and the presence of etiological agents, increasing the prevalence of lung disease in workers. Free-stall farms, however, are more spacious and modern than tie-stall farms. This study characterizes air quality in free-stall and tie-stall farms (dust, total bacteria, Penicillium/Aspergillus, archaea, and endotoxins). It also focuses on detecting airborne etiological agents and indicators of fecal contamination, as well as assessing the effect of environmental factors on air quality. Five farms of each type (free housing and tie housing) using straw bedding material and equipped with mechanical ventilation were visited. Sampling visits were conducted in winter with no activity (e.g., bedding spreading) in buildings. Dust was evaluated using the DustTrakTM DRX Aerosol Monitor, and bioaerosols were sampled in triplicates for 10 minutes using the SASS®3100 Dry Air Sampler. Finally, soiled bedding was collected throughout the barn. No type of housing seems to be linked with poorer air quality, but some air quality indicators stood out in some outliers. The most recently designed free-housing buildings and the greater air volume may have played a role in the absence of detected differences. Escherichia coli, Enterococcus spp., Clostridium perfringens, Aspergillus fumigatus, Staphylococcus aureus, Saccharopolyspora rectivirgula, Coxiella burnetii, and Klebsiella pneumoniae were detected in high concentrations in both types of buildings. Soiled bedding concentrations, ventilation rates, and animal density seemed to have a significance on air quality in dairy barns. Keywords: Air Quality, Bioaerosols, Housing, Occupational exposure.

THE EFFECT OF ESCHERICHIA COLI BACTERIOPHAGE COCKTAIL ON BACTERIAL CONTAMINATION IN WATER

Objective: Wastewater and environmental water resources are treated to eliminate pathogenic microorganisms but contamination is still a significant problem. In particular, the presence of contamination with Escherichia coli (E. coli) is an important indicator of fecal contamination. Due to increasing antimicrobial resistance and failures of new antimicrobial processes, interest in bacteriophages in pathogen control has increased. Therefore, in our study, phage-based bacteria control in environmental waters was investigated as a natural solution. Material and Method: In our study, E. coli and lytic bacteriophages specific to these E. coli were isolated from environmental water samples in Ankara. The lytic activities of the isolated phages were determined on environmental and clinical extended-spectrum β-lactamases E. coli isolates. Three phages with high lytic activity were selected, and the effectiveness of the single phage and their mixtures on E. coli contamination in water was tested. Result and Discussion: As a result of the study, 17 E. coli strains were isolated from 30 environmental water samples. Lytic bacteriophages in 30 different plaque structures were also isolated from water samples. The isolated phages were found to have lytic activity in the range of 32-70% on the tested bacteria. The effectiveness of three selected phages and their cocktail on E. coli contamination in water was measured at 6th and 24th. As a result, it was observed that the cocktail application reduced the number of host bacteria in the water below detectable limits, also provided a 5-log reduction in non-host test bacteria and maintained its effect for 24 hours. When the results are evaluated, it is thought that cocktail phage application will be an effective method against E. coli contamination in water.

High microbiological contamination in surface waters in the upper basin of the Choluteca River in Honduras

Microorganisms with a high pathogenic potential for humans and animals can spread through water. This represents a severe threat to public health, particularly in low- and middle-income countries where sanitation conditions are often limited. Due to their constant presence in the intestine and feces of both people and animals, total coliforms, thermotolerant coliforms, and intestinal Enterococcus have historically been employed as indicators of fecal contamination to evaluate water quality for human use and consumption. Under no circumstances should water sources for human use and consumption have bacteria indicating fecal contamination. The objective of this study was to evaluate the microbiological quality of surface water from six sub-basins located in the upper basin of the Cholulteca River in Honduras and determine the Escherichia coli phylogroups isolated in these samples. Our results show high rates of fecal contamination, suggesting that surface waters in the upper Choluteca River basin are unsafe for human consumption. Phylogroups B1 and D were the most frequent among 29 E. coli isolates, while phylogroups C and F were the least frequent. Measures must be taken to raise awareness about sanitation and good practices for managing household waste and those generated by agro-industrial and livestock activities in the area. Surface water in the Choluteca River basin must be adequately treated before consumption because it may impact people's health. In addition, we encourage prompt decision-making by the health authorities. In conclusion, this study assessed the microbiological quality of water in the upper Choluteca River basin. Our findings show high rates of fecal contamination and the predominance of E. coli strains from phylogroups associated with fecal contamination, suggesting that these waters are unsafe for human consumption. Keywords: fecal contamination; E. coli; phylogroups; surface water; Choluteca River basin; Honduras