Fecal Indicator Research Articles

Identification of antibiotic-resistant pathogens and virulence genes in Escherichia coli isolates from food samples in the Dhaka University campus of Bangladesh.

The presence of antibiotic-resistant pathogens in food is a serious public health concern nowadays. This study focuses on the isolation and characterization of potentially pathogenic Escherichia coli and antimicrobial-resistant pathogens in chicken curry and potato smash samples collected from the canteens and cafeteria of Dhaka University in Bangladesh. Isolates were identified by their cultural, morphological, and biochemical tests (motility indole urease test, Kliger's iron agar test, catalase test, oxidase test, methyl red and Voges-Proskauer tests). The antibiotic susceptibility test was done by the disk diffusion method. The range of total bacterial count in the potato smash and chicken curry samples was from 1.4 × 104 to 1.6 × 108 CFU/g and from 2.4 × 103 to 2.6 × 106 CFU/g, respectively. Escherichia coli, Salmonella, Vibrio, Klebsiella, Citrobacter, Enterobacter, Proteus, Clostridium, Staphylococcus, Streptococcus, Micrococcus, Bacillus, and Sarcina strains were isolated in both samples. Isolates were highly resistant to ampicillin (90.90%) followed by colistin (52.27%), azithromycin (27.27%), and tetracycline 25%. Proteus species had the highest rate of multiple antibiotic resistance (MAR; 62.5%), followed by Citrobacter species (50%). The isolated E. coli strains were further analyzed through PCR assay to detect virulent genes (EPEC: eaeA 229 bp, bfpA 450 bp, ETEC elt 322 bp, EHEC hylA 534 bp, and EIEC ial 320 bp). One E. coli isolate had the eaeA target gene under EPEC pathotypes. Escherichia coli, as a fecal indicator, may indicate fecal contamination or poor and unhygienic food handling. The findings recommend further investigations to identify potential mechanisms of contamination and preventive measures to improve the food safety level in the canteens and restaurants.

Evaluation of selective clay minerals and biochar as materials for sewage sludge stabilization

The objectives of this study were to evaluate sewage sludge’s stabilization with untested until now materials, such as selective clay minerals or biochar in comparison with liming, for enhancing sludge’s fertilization capacity. Dewatered sewage sludge was mixed with bentonite, vermiculite, zeolite, biochar or lime at rates of 0, 15 and 30%, air-dried and analyzed for pathogens and chemical properties. Almost all fecal indicators of treated sludge with 15% bentonite, vermiculite or biochar were reduced by at least one-logarithmic unit (log10) (indicative value of sludge’s stabilization), whereas those of limed sludge were undetectable. Electrical conductivity of all treatments significantly increased, and the highest values were obtained for untreated (6.1 dS m−1) and limed sludge (above 7.0 dS m−1 for both addition rates). The untreated sludge had the significantly highest water-soluble ammonium-nitrogen (2817 mg kg−1) and phosphorus (263 mg kg−1) concentrations followed by sludge treated with bentonite, vermiculite or biochar, whereas limed sludge had the lowest content. Boron concentration of the untreated sludge was similar to the treated sludge. Total concentrations of heavy metals were far below the legislative permissible levels for sludge’s agronomic use. Nutrients’ total content of treated sludge ranged at levels of similar magnitude to the untreated sludge, except for certain cases where they were increased because of the materials’ composition. Consequently, sewage sludge treated with 15% bentonite, vermiculite or biochar seems to be stabilized, retain bioavailable nitrogen and serve as a fertilizer of macro- and micronutrients. However, potential risks of agronomic use, i.e., soil salinization and boron phytotoxicity, should be considered.

Assessing the Occurrence of Host-Specific Faecal Indicator Markers in Water Systems as a Function of Water, Sanitation and Hygiene Practices: A Case Study in Rural Communities of Vhembe District Municipality, South Africa.

In settings where humans and animals closely coexist, the introduction of faecal material into unprotected water sources significantly increases the risk of contracting diarrhoeal and zoonotic waterborne diseases. The data were gathered from a survey conducted through interviews at randomly sampled villages; additionally, water samples were collected in randomly selected households and their associated feeder catchments. Molecular techniques were used, specifically qPCR, to run host-specific Bacteroides microbial source tracking (MST) assays for human, cattle, pig, chicken and dog faecal contamination. Unexpectedly, the qPCR assays revealed dogs to be the most prevalent (40.65%) depositor of faecal matter in unprotected surface water, followed by humans (40.63%); this finding was contradictory to survey findings indicating cattle as the leading source. At the household level, dogs (16.67%) and chickens (15.28%) played prominent roles, as was expected. Reflecting on some of the basic daily practices in households, nearly 89.00% of the population was found to store water due to erratic supply, in contrast to 93.23% using an improved water source. Additionally, a significant association was found between water, sanitation and hygiene (WASH) variables and the occurrence of MST markers after performing a bivariate linear regression. However, the inconsistency between the MST results and household surveys suggests pervasive sanitation issues, even in households without domesticated animals.

Metagenomics-Based Microbial Ecological Community Threshold and Indicators of Anthropogenic Disturbances in Estuarine Sediments.

Assessing the impacts of cumulative anthropogenic disturbances on estuarine ecosystem health is challenging. Using spatially distributed sediments from the Pearl River Estuary (PRE) in southern China, which are significantly influenced by anthropogenic activities, we demonstrated that metagenomics-based surveillance of benthic microbial communities is a robust approach to assess anthropogenic impacts on estuarine benthic ecosystems. Correlational and threshold analyses between microbial compositions and environmental conditions indicated that anthropogenic disturbances in the PRE sediments drove the taxonomic and functional variations in the benthic microbial communities. An ecological community threshold of anthropogenic disturbances was identified, which delineated the PRE sediments into two groups (H and L) with distinct taxa and functional traits. Group H, located nearshore and subjected to a higher level of anthropogenic disturbances, was enriched with pollutant degraders, putative human pathogens, fecal pollution indicators, and functional traits related to stress tolerance. In contrast, Group L, located offshore and subjected to a lower level of anthropogenic disturbances, was enriched with halotolerant and oligotrophic taxa and functional traits related to growth and resource acquisition. The machine learning random forest model identified a number of taxonomic and functional indicators that could differentiate PRE sediments between Groups H and L. The identified ecological community threshold and microbial indicators highlight the utility of metagenomics-based microbial surveillance in assessing the adverse impacts of anthropogenic disturbances in estuarine sediments, which can assist environmental management to better protect ecosystem health.

Diversity of Fecal Indicator Enterococci among Different Hosts: Importance to Water Contamination Source Tracking.

Enterococcus spp. are common bacteria present in the intestinal tracts of animals and are used as fecal indicators in aquatic environments. On the other hand, enterococci are also known as opportunistic pathogens. Elucidating their composition in the intestinal tracts of domestic animals can assist in estimating the sources of fecal contamination in aquatic environments. However, information on the species and composition of enterococci in animal hosts (except humans) is still lacking. In this study, enterococci were isolated from the feces of cattle, pigs, birds, and humans using selective media. Enterococcal species were identified using mass spectrometry technology, and each host was characterized by diversity and cluster analysis. The most dominant species were E. hirae in cattle, E. faecium in birds, and E. faecalis in pigs and humans. Cattle had the highest alpha diversity, with high interindividual and livestock farm diversity. The dominant enterococcal species in pigs and humans were identical, and cluster analysis showed that the majority of the two hosts' species clustered together.

Effect of greywater treated by horizontal subsurface flow wetlands planted with Chrysopogon zizanioides and Andropogon gayanus on the germination of tomato (Lycopersicon esculentum Mill.) seeds under Sahelian climate

Greywater reuse for agricultural irrigation may contribute to reduce pressure on scarce freshwater sources and the use of chemical fertilizers in Sahelian countries. However, treatment methods that reduce the harmful effects of untreated greywater are essential for sustainable agriculture. This study aims to evaluate greywater treatment capacity by Horizontal Subsurface Flow wetlands (HSSF) planted with Chrysopogon zizanioides (HSSF-C) and Andropogon gayanus (HSSF-A), and to investigate the suitability of the effluents on the germination of tomato seeds. Three pilot-scale HSSF (planted with Chrysopogon zizanioides or Andropogon gayanus and an unplanted (control)) were designed and their removal efficiencies of organic matter, nutrients and fecal bacteria were evaluated. Principal component analysis showed planted systems provided higher removal efficiencies than the unplanted system. HSSF-A showed the best performance for removal of organic (COD, BOD5) and mineral (NO3−, NH4+) matter while HSSF-C showed the best performance for removal of phosphorus compounds and fecal indicators (thermotolerant coliforms, E. coli). HSSF-UP showed the lowest performance for removal of all parameters. The reduction of thermotolerant coliforms and E. coli were significantly greater in the two planted systems and exceeded 2 log10 removal. However, no significant difference was observed between the planted and unplanted HSSF for fecal indicators. Furthermore, germination rates obtained with greywater treated by HSSF were higher than 80%, approaching that obtained using distilled water, while the lower germination rates were observed with seeds irrigated with raw greywater (58%). This is a clear indication of the beneficial effect of treated greywater by HSSF wetlands on seeds germination. In addition, residual content of fecal indicators and physicochemical characteristics of the treated greywater are compliant with WHO reuse guidelines for restricted irrigation. The results demonstrate the possibility of using constructed wetlands for greywater treatment and its reuse in gardening in Sahelian countries.

Physicochemical and bacteriological assessment of Wupa wastewater treatment plant effluent and the effluent-receiving Wupa River in Abuja, Nigeria.

The occurrence of pathogens in discharged wastewater effluent may constitute potential public health risks. This study assessed the physicochemical and bacteriological characteristics of water samples taken from the Wupa River in Abuja, Nigeria, which receives the final effluent of the Wupa Wastewater Treatment Plant. Sixty sewage/water samples were collected over 12 months from five sampling points. Coliform bacteria and Escherichia coli were simultaneously enumerated using the membrane filtration technique and Chromocult Coliform Agar. HANNA multiparameter metre was used to measure the physicochemical parameters including temperature, pH, electrical conductivity (EC), dissolved oxygen (DO) and total dissolved solids (TDS). Results of the bacteriological analysis showed that impermissible high mean counts of E. coli (≥ 1.2 × 104 CFU/100 ml) and total coliforms (≥ 5.4 × 104 CFU/100 ml) were detected in 95% and 100% of the water samples respectively. These values exceed the acceptable standard limits. The mean values of physicochemical parameters ranged from 6.3 to 8.7, 20.9 to 27.3 °C, 116 to 325.0 µS/cm, 1.3 to 11.4 mg/l and 98.0 to 180.0 mg/l for pH, temperature, EC, DO and TDS respectively, with all conforming to international and national standards. Wupa River seems to have a minor negative environmental impact, per the physicochemical data obtained in this study. However, the high counts of faecal indicator bacteria demonstrated in the effluent samples were higher than those of the river at both upstream and downstream sites, implying that the river microbial load may increase to constitute an unchecked environmental hazard. Adequate disinfection of the Wupa plant effluent before discharge into the Wupa River is imperative.

Bacteroidales as a fecal contamination indicator in fresh produce industry: A baseline measurement

Foodborne outbreaks caused by fecal contamination of fresh produce represent a serious concern to public health and the economy. As the consumption of fresh produce increases, public health officials and organizations have pushed for improvements in food safety procedures and environmental assessments to reduce the risk of contamination. Visual inspections and the establishment of "buffer zones" between animal feeding operations and producing fields are the current best practices for environmental assessments. However, a generalized distance guideline and visual inspections may not be enough to account for all environmental risk variables. Here, we report a baseline measurement surveying the background Bacteroidales concentration, as a quantitative fecal contamination indicator, in California's Salinas Valley. We collected a total of 1632 samples from two romaine lettuce commercial fields at the time of harvesting through two seasons in a year. The quantification of Bacteroidales concentration was performed using qPCR, revealing a notably low concentration (0–2.00 copies/cm2) in the commercial fields. To further enhance the applicability of our findings, we developed a user-friendly method for real-world fecal contamination risk assessment that seamlessly integrates with industry practices. Through the generation of heatmaps that visually illustrate varying risk levels across fields, this approach can identify site-specific risks and offer fresh produce stakeholders a more comprehensive understanding of their land. We anticipate this work can encourage the use of Bacteroidales in the fresh produce industry to monitor fecal contamination and prevent future foodborne outbreaks.

Multiscale spatiotemporal variability of fecal indicator bacteria and associated particle size distributions in the sandy bottom sediments of a Pennsylvania creek.

Concentrations of the fecal indicator bacteria (FIB)Escherichia coliand enterococci are used to assess microbial impairment in irrigation and recreation water sources. Although the FIB concentrations' variability at large temporal scales, such as seasons, and large spatial scales encompassing different land use has been studied, the knowledge about smaller scale variability remains sparse. This work aimed to research the small-scale variability ofE. coliand enterococci in a montane creek with sandy bottom sediments. Sediment samples were collected weekly for a year in triplicate at sampling sites in aforested headwater, an agricultural area, and a mixed urban-agricultural area. The average weekly change in concentrations was from two times at the forested site to five times at the urban-agricultural site. Mean relative deviations from averages across sampling locations increased from -25% at the forested site to 45% at the urban-agricultural site. This trend was also observed separately over the cold and warm seasons. Over a week without precipitation, E. coliconcentrations decreased on average by 20% in warm period and by 45% in cold period; the enterococci concentration declined by 12% in both cold and warm periods. The sediment particle size distributions were significantly different among the three sites and between the cold and warm seasons. Rankings of sediment fine mass fractions and FIB concentrations were positively correlated at two of three sampling sites in more than 70% of observation dates. The results of this work indicate the need to evaluate the uncertainty of sediment FIB concentrations before designing sediment FIB monitoring quality.

Microbial community of municipal drinking water in Hangzhou using metagenomic sequencing

While traditional culture-dependent methods can effectively detect certain microorganisms, the comprehensive composition of the municipal drinking water (DW) microbiome, including bacteria, archaea, and viruses, remains unknown. Metagenomic sequencing has opened the door to accurately determine and analyze the entire microbial community of DW, providing a comprehensive understanding of DW species diversity, especially in the context of public health concerns during the COVID-19 era. In this study, we found that most of the culturable bacteria and some fecal indicator bacteria, such as Escherichia coli and Pseudomonas aeruginosa, were non-culturable using culture-dependent methods in all samples. However, metagenomic analysis showed that the predominant bacterial species in the DW samples belonged to the phyla Proteobacteria and Planctomycetes. Notably, the genus Methylobacterium was the most abundant in all water samples, followed by Sphingomonas, Gemmata, and Azospirilum. While low levels of virulence-associated factors, such as the Esx-5 type VII secretion system (T7SS) and DevR/S, were detected, only the erythromycin resistance gene erm(X), an rRNA methyltransferase, was identified at low abundance in one sample. Hosts corresponding to virulence and resistance genes were identified in some samples, including Mycobacterium spp. Archaeal DNA (Euryarchaeota, Crenarchaeota) was found in trace amounts in some DW samples. Viruses such as rotavirus, coxsackievirus, human enterovirus, and SARS-CoV-2 were negative in all DW samples using colloidal gold and real-time reverse transcription polymerase chain reaction (RT‒PCR) methods. However, DNA encoding a new order of reverse-transcribing viruses (Ortervirales) and Herpesvirales was found in some DW samples. The metabolic pathways of the entire microbial community involve cell‒cell communication and signal secretion, contributing to cooperation between different microbial populations in the water. This study provides insight into the microbial community and metabolic process of DW in Hangzhou, China, utilizing both culture-dependent methods and metagenomic sequencing combined with bioinformatics tools during the COVID-19 pandemic era.

Implementing an adaptive, two-tiered SARS-CoV-2 wastewater surveillance program on a university campus using passive sampling

Building-level wastewater-based surveillance (WBS) has been increasingly applied upstream from wastewater treatment plants to conduct targeted monitoring for SARS-CoV-2. In this study, a two-tiered, trigger-based wastewater surveillance program was developed on a university campus to monitor dormitory wastewater. The objective was to determine if passive sampling with cotton gauze as a sampling medium could be used to support institution-level public health action. Two nucleocapsid gene targets (N1 and N2) of SARS-CoV-2 as well as the endogenous fecal indicator pepper mild mottle virus (PMMoV) were quantified using RT-qPCR. >500 samples were analyzed during two contrasting surveillance periods. In the Fall of 2021 community viral burden was low and a tiered sampling network was able to isolate individual clinical cases at the building-scale. In the Winter of 2022 wastewater signals were quickly elevated by the emergence of the highly transmissible SARS-CoV-2 Omicron (B.1.1.529) variant. Prevalence of SARS-CoV-2 shifted surveillance objectives from isolating cases to monitoring trends, revealing both the benefits and limitations of a tiered surveillance design under different public health situations. Normalization of SARS-CoV-2 by PMMoV was not reflective of upstream population differences, suggesting saturation of the material occurred during the exposure period. The passive sampling method detected nearly all known clinical cases and in one instance was able to identify one pre-symptomatic individual days prior to confirmation by clinical test. Comparisons between campus samplers and municipal wastewater influent suggests that the spread of COVID-19 on the campus was similar to that of the broader community. The results demonstrate that passive sampling is an effective tool that can produce semi-quantitative data capable of tracking temporal trends to guide targeted public health decision-making at an institutional level. Practitioners of WBS can utilize these results to inform surveillance program designs that prioritize efficient resource use and rapid reporting.

Microbial source tracking of fecal pollution to coral reef lagoons of Norfolk Island, Australia

Fecal pollution contributes to global degradation of water quality and requires identification of the source(s) for predicting human health risk, tracking disease, and developing management strategies. While fecal indicator bacteria are commonly used to detect fecal pollution, they cannot identify sources. Novel approaches, such as microbial source tracking (MST), can be applied to evaluate the origin of fecal pollution. This study examined fecal pollution in the coral reef lagoons of Norfolk Island, Australia where reef health decline has been related to nutrient input. The primary objective of this study was to evaluate the host sensitivity and specificity of two human wastewater-associated marker genes (Bacteroides HF183 (HF183) and cross-assembly phage (crAssphage)) and four animal feces associated marker genes targeting avian, ruminant, dog, and pig (Helicobacter-associated GFD (GFD), Bacteroides BacR (BacR), Bacteroides DogBact (DogBact), and Bacteroides Pig-2-Bac (Pig-2-Bac)) in wastewater and animal fecal samples collected from Norfolk Island. The prevalence and concentrations of these marker genes along with enterococci genetic marker (ENT 23S rRNA) of general fecal pollution and human adenovirus (HAdV), which is considered predominantly a pathogen but also a human-wastewater associated marker gene, were determined in surface, ground, and marine water resources. A secondary objective of this study was to assess the sources and pathways of fecal pollution to a sensitive marine environment under rainfall events. HF183, crAssphage, HAdV, and BacR demonstrated absolute host sensitivity values of 1.00, while GFD and Pig-2-Bac had host sensitivity values of 0.60, and 0.20, respectively. Host specificity values were > 0.94 for all marker genes. Human and animal (avian, ruminant, dog) fecal sources were present in the coral reef lagoons and surface water whereas groundwater was polluted by human wastewater markers. This study provides understanding of fecal pollution in water resources on Norfolk Island, Australia after precipitation events. The results may aid in effective water quality management, mitigating potential adverse effects on both human and environmental health.

Diurnal changes in pathogenic and indicator virus concentrations in wastewater

Wastewater-based epidemiology (WBE) has been commonly used for monitoring SARS-CoV-2 outbreaks. As sampling times and methods (i.e. grab vs composite) may vary, diurnal changes of viral concentrations in sewage should be better understood. In this study, we collected untreated wastewater samples hourly for 4 days at two wastewater treatment plants in Wales to establish diurnal patterns in virus concentrations and the physico-chemical properties of the water. Simultaneously, we also trialled three absorbent materials as passive samples as a simple and cost-efficient alternative for the collection of composite samples. Ninety-six percent of all liquid samples (n = 74) and 88% of the passive samplers (n = 59) were positive for SARS-CoV-2, whereas 87% and 97% of the liquid and passive samples were positive for the faecal indicator virus crAssphage, respectively. We found no significant daily variations in the concentration of the target viruses, ammonium and orthophosphate, and the pH and electrical conductivity levels were also stable. Weak positive correlations were found between some physico-chemical properties and viral concentrations. More variation was observed in samples taken from the influent stream as opposed to those taken from the influent tank. Of the absorbent materials trialled as passive samples, we found that tampons provided higher viral recoveries than electronegative filter paper and cotton gauze swabs. For all materials tested, viral recovery was dependent on the virus type. Our results indicate that grab samples may provide representative alternatives to 24-h composite samples if taken from the influent tank, hence reducing the costs of sampling for WBE programmes. Tampons are also viable alternatives for cost-efficient sampling; however, viral recovery should be optimised prior to use.

Short-term impacts of a large cultural event on the microbial pollution status of a pre-alpine river.

Rivers are impacted by microbial faecal pollution from various sources. We report on a short-term faecal pollution event at the pre-alpine Austrian river Traisen caused by the large cultural event FM4 Frequency music festival, with around 200,000 visitors over 4 days. We observed a massive increase of the faecal indicator bacteria (FIB) intestinal enterococci during the event, while Escherichia coli concentrations were only slightly elevated. This increase poses a significant potential health threat to visitors and people recreating downstream of the festival area. A plausible explanation for the uncoupling of the two FIBs may have been a differential persistence caused by a combination of factors including water temperature, solar radiation, and the excessive presence of personal care products (PCPs) in the river water. However, a potential impact of PCPs on FIB assay performance cannot be ruled out. Our observations are relevant for other intensively used bathing sites; detailed investigations on persistence and assay performance of the FIB in response to different ingredients of PCPs are highly recommended. We conclude that for future festivals at this river or other festivals taking place under similar settings, a more effective management is necessary to reduce deterioration in water quality and minimise health risks.

Integrating molecular microbial methods to improve faecal pollution management in rivers with designated bathing waters

Rivers are at risk from a variety of pollution sources. Faecal pollution is of particular concern since it disperses pathogenic microorganisms in the aquatic environment. Currently, faecal pollution levels in rivers is monitored using faecal indicator bacteria (FIB) that do not offer information about pollution sources and associated risks. This study used a combined molecular approach, along with measurements of water quality, to gain information on pollution sources, and risk levels, in a newly designated recreational bathing site in the River Wharfe (UK). Physico-chemical parameters were monitored in situ, with water quality multiparameter monitoring sondes installed during the 2021 bathing season. The molecular approach was based on quantitative PCR (qPCR)-aided Microbial Source Tracking (MST) and 16S rRNA gene metabarcoding to obtain a fingerprint of bacterial communities and identify potential bioindicators.The analysis from the water quality sondes showed that ammonium was the main parameter determining the distribution of FIB values. Lower faecal pollution levels were detected in the main river when compared to tributaries, except for samples in the river located downstream of a wastewater treatment plant. The faecal pollution type (anthropogenic vs. zoogenic) changed the diversity and the structure of bacterial communities, giving a distinctive fingerprint that can be used to inform source. DNA-based methods showed that the presence of human-derived bacteria was associated with Escherichia coli spikes, coinciding with higher bacterial diversity and the presence of potential pathogenic bacteria mainly of the genus Mycobacterium, Aeromonas and Clostridium. Samples collected after a heavy rainfall event were associated with an increase in Bacteroidales, which are markers of faecal pollution, including Bacteroides graminisolvens, a ruminant marker associated with surface run-off from agricultural sources. The combined use of qPCR and 16S rRNA sequencing was able to identify pollution sources, and novel bacterial indicators, thereby aiding decision-making and management strategies in recreational bathing rivers.

Impact of heat-treatment on wastewater analytical parameters

Abstract Raw wastewater analysis is an important step in treatment assessment; however, it is associated with risks of personnel exposure to pathogens. Such risks are enhanced during virus outbreaks, such as the COVID pandemic, and heat-treatment is a commonly used mitigation measure. We examined whether heat-treatment compromises wastewater analytical parameters results. We found that heat-treatment of blackwater at 60 °C for 90 min in capped containers yielded no statistically different values (p > 0.05) for pH, chemical oxygen demand (COD), ammonia (NH3), total nitrogen (TN), total suspended solids (TSS), and turbidity for specimens from three different sources. This heat-treatment inactivated coliform bacteria (>4 log10 reduction) thus compromising the measurement of commonly used fecal contamination indicators. The observation of intact helminth eggs in heat-treated specimens suggests that the helminth egg enumeration assay is not compromised. These findings indicate that heat-treatment for the safe handling of wastewater, as may be needed in future virus outbreaks, does not affect the measurements of many common wastewater physico-chemical properties.

Total alditols from Cistanche deserticola attenuate functional constipation by regulating bile acid metabolism

Headings ethnopharmacological relevanceFunctional constipation (FC), characterized by chronic constipation, significantly impacts physiological function and induces psychological stress in patients. However, current clinical treatment options for FC are currently limited. Cistanche deserticola, a traditional Chinese medicine that promotes intestinal moisture and bowel relaxation, contains cistanche total alditol extract (CTAE) as its primary active extract. However, the production of CTAE, its overall efficacy, and potential mechanisms for treating FC have yet to been investigated. Aim of the studyThis study aimed to reveal the overall efficacy and potential mechanism of action of CTAE in rats with FC using a combination of stable preparation, pharmacodynamics, non-targeted metabolomics, bile acid metabolomics, and western blotting. Materials and methodsFourteen batches of CTAE underwent quality testing. A rat model of FC was developed using diphenoxylate tablets. The comprehensive pharmacodynamic effects of CTAE on FC were evaluated using fecal characteristics (wet weight, dry weight, and water content), intestinal transmission (colonic EMG amplitude, colonic EMG frequency, propulsion length, and propulsion rate), serum and colon biochemical indicators, distribution of interstitial cells of Cajal (ICC), and pathological examination. Non-targeted metabolomics was performed to assess the changes in endogenous metabolite profiles induced by CTAE. Bile acid metabolomics and western blotting analyses were employed to validate the potential mechanisms of action of CTAE. ResultsCTAE, with a total content of betaine, mannitol, D-fructose, glucose, and sucrose of (75.67 ± 3.73) %, significantly enhanced intestinal transit, regulated neurotransmitters, increased the expression of c-kit in ICC, and alleviated intestinal inflammation in rats with FC. Non-targeted metabolomics revealed that CTAE significantly alleviated FC-induced metabolic disorders, mainly the biosynthesis of primary bile acids. Targeted metabolomic analysis confirmed that CTAE regulated FC-induced bile acid disorders. Western-blotting results confirmed that CTAE increased the expression of CYP8B1, FGF15, TGR5, and FXR, thereby modulating bile acid synthesis and enterohepatic circulation. ConclusionCTAE demonstrates significant therapeutic effects on FC, primarily through the regulation of bile acid synthesis and enterohepatic circulation. These findings provide a promising foundation for the development and clinical application of novel CATE-based drugs.

Modelling faecal microbe dynamics within stormwater constructed wetlands

Modelling faecal microbe levels is performed widely in natural and wastewater wetlands, yet these predictions can be challening due to highly stochastic storm events. In our study, a coupled hydrodynamic and microorganism model was developed and tested to predict the long-term faecal microbial removal in stormwater constructed wetlands. The microorganism model simulates the fate and transport of the faecal indicator organism Escherichia coli (E. coli), resolving advection-dispersion, sedimentation, resuspension and die-off based on temperature and UV exposure. The model was tested using a two-year monitoring dataset collected from Troups Creek wetland, a multiple-inflow stormwater wetland in Melbourne, Australia. The model parameter values applied in the coupled model were based on a mixture of site-specific data and values obtained from literature. The only adjusted parameter in our microorganism model was the die-off rate in dark conditions in the stormwater wetlands. An urban stormwater microorganism model, MOPUS, was used to generate continuous catchment E. coli loading rates as input to the wetland. The hydrodynamic model was evaluated using flow rate monitored at the outlet weir, achieving Nash- Sutcliffe Efficiency (E) values of 0.86 over the two-year monitoring period. The E. coli model was tested using outflow E. coli concentration data and achieved an overall E of 0.37. The performance of the microbial model was variable across the 22 monitored events, with E ranging from <0 to 0.8. Sensitivity tests were performed to evaluate the model outputs and the results indicated that (a) the importance of collecting high-quality data for stormwater inputs into wetlands and (b) the importance of accurate estimation of the die-off rate in wetland microbial removal models. Our research showed that this model can be used to help design and rectify stormwater constructed wetlands for better faecal microbial removal, vegetation maintenance and support future real-time decision-making.

Assessment of spatio-temporal variation in microbial quality of groundwater for irrigation and drinking water: A case study in Santa Lucia canton, Ecuador

The community of Paipayales is placed in the Santa Lucía Canton of Guayas Province, Ecuador. The residents rely mainly on well water for irrigation of their agricultural products, as well as for consumption. This study aimed to evaluate the temporal and spatial variation in microbial quality among different wells in Paipayales. Additionally, the research aimed to identify potential sources of contamination by assessing the association between groundwater microbial sources and land use patterns. The microbiological and physicochemical quality of 26 water wells were studied across 16 months. Samples were taken at the end of dry season in November 2018 (ED), beginning of dry season June 2019 (BD), and rainy season February 2020 (RS). Overall, the mean values of all studied microorganisms were found to be lowest in ED, followed by BD and RS. Fecal indicators microorganisms displayed less variability compared to heterotrophic aerobic bacteria, and Pseudomonas, all of which showed significant differences between years (p < 0.01). No significant difference was found between microorganisms and well characteristics. Out of the analyzed E. coli strains, seven (16.66%) exhibited resistance to at least one antibiotic, and two strains were found to be multiresistant. These findings indicate the influence of activities such as rice cultivation and animal husbandry near the wells, as well as the absence of proper sanitation facilities in their vicinity. Turbidity increased from 2018 to 2020, while pH, temperature, and salinity showed minimal variation across all years, with only a few samples displaying correlation. Most wells met the Ecuadorian guidelines for drinking water after disinfection, with only one sample failing to meet the irrigation standards. The results suggest that microbial communities in groundwater aquifers are primarily influenced by external factors, notably anthropogenic activities related to agriculture and urbanization in the area.

Faecal contamination and its relationship with some environmental variables of four urban rivers in inner Hanoi city, Vietnam

Coliform bacteria are essential variables for assessing riverine water quality. In this study, the faecal indicator bacteria (FIB) in relationship with some physico-chemical variables were investigated during the period 2020-2022 for four urban rivers (To Lich, Lu, Set, and Kim Nguu) in the inner Hanoi city to provide the updated water quality of these rivers. The results demonstrated severe faecal coliforms contamination in riverine waters compared to the permissible values of the Vietnam technical regulation for surface water quality, QCVN08-MT:2015/BTNMT column B1. Nutrients (ammonium and phosphate) concentrations and dissolved oxygen (DO) values exceeded the permissible values, whereas pH was within the standard. The Pearson analysis demonstrated the significant positive correlation between total coliforms (TC) and Escherichia coli (EC) densities and ammonium concentration in the riverine water. Besides, these variables were higher in the dry season than the rainy one for all sites observed. All these reflect the critical role of the point sources, notably domestic wastewater inputs in the four river basins. Considering these rivers' deteriorating condition, developing an effective wastewater treatment system is necessary for the rivers in Hanoi.