Fecal Contamination Research Articles

Parasites Observed in Urine Sediments: A Rare but Convincing Truth

Aim: To reveal the urgency to understand and augment the recognizance of the possibility existence of parasitic materials on cytological evaluation of urine.
 Discussion: Urine is always contemplated as an ideal diagnostic specimen due to its direct and easiness to collect that surely non-invasive. Three common parasites that can be found in urine are Trichomonas vaginalis, Schistosoma hematobium and microfilaria of Wuchereria bancrofti. Other parasites and parasitic ova may also be seen in urinary sediments as a result of fecal or vaginal contamination. Urine Parasitological analysis embraces a wide expansive areas of tests, which comprise an assortment of physico-macroscopic analysis, microscopic analysis on cells and Parasite-bacterial appearance, parasite and microbe cultures, chemical tests, and even can be extended up to molecular identification. Importantly, from urine samples, a confirmed Parasitological diagnosis (and also Microbiology and other kind of disease) can be made through definite tests.
 Conclusion: In the context of allegation of parasite as an etiological agent, thorough morphological detection via careful sediment microscopic analysis helps in making early and correct diagnosis in most cases.

Occurrence and temporal distribution of extended-spectrum β-lactamase-producing Escherichia coli in clams from the Central Adriatic, Italy.

The spread of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli is a major public health issue. Bivalves are filter-feeder animals capable of bioaccumulating the microorganisms present in water. This physiological characteristic makes them both good indicators of environmental contamination and possible carriers of pathogenic bacteria, including those resistant to antimicrobials. The aim of this study was to investigate the occurrence of ESBL-producing E. coli in clams (n = 308) collected from harvesting areas of the Central Adriatic Sea between 2018 and 2019. ESBL- /class C β-lactamase (AmpC)- producing E. coli and Escherichia spp. were isolated by streaking over the surface of MacConkey agar plates supplemented with cefotaxime enriched broths of the initial shellfish suspension. E. coli and Escherichia spp. resistant to cefotaxime were screened for ESBL production by using the double disk synergy test. Susceptibility to different antimicrobials and confirmation of ESBL-production were determined by the minimum inhibitory concentration (MIC) test. Isolates were further characterized by whole genome sequencing (WGS) and bioinformatic analysis of genomes with different tools. Overall, ESBL-producing E. coli were isolated from 3% of the samples. Of 13 ESBL- and ESBL-/AmpC-producing Escherichia spp. (n = 11 E. coli, n = 1 E. marmotae, n = 1 E. ruysiae) isolates, 13 were resistant to ampicillin and cefotaxime, 9 to sulfamethoxazole, 6 to tetracycline and nalidixic acid, 4 to trimethoprim, and 3 to ceftazidime, cefoxitin, ciprofloxacin, and chloramphenicol. Moreover, the majority (8/11) of the ESBL-producing E. coli isolates were multidrug-resistant. WGS showed that the isolates predominantly carried the blaCTX-M-15 gene (3/11) and blaCTX-M-14 and blaCTX-M-1 (2/11 each). The AmpC β-lactamase CMY-2 was found in two isolates. Phylogroup A was the most prevalent (5/11), followed by phylogroups D (4/11), F (1/11), and B2 (1/11). Ten different sequence types (STs) were identified. Occurrence at sampling sites ranged between 0 and 27%. To identify associations between the occurrence of ESBL-producing E. coli and E. coli levels, samples were divided into two groups, with E. coli at >230 MPN/100 g and E. coli at ≤230 MPN/100 g. ESBL-producing E. coli isolates were significantly more commonly recovered in samples with higher E. coli levels (14%) than in those with lower levels of E. coli (2%). Moreover, the majority (3/4) of the potentially pathogenic strains were isolated in samples with higher E. coli levels. These findings provided evidence for the bacterial indicator of fecal contamination, E. coli, as an index organism for ESBL-producing E. coli isolates in bivalves.

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.

The efficacy of hydrogen sulfide (H2S) tests for detecting microbial contamination in rooftop-harvested rainwater

As climate change strains the world’s freshwater resources, access to safe and clean water becomes limited. The use of alternative water sources, such as rooftop-harvested rainwater, has become one mechanism to address freshwater scarcity in the American Southwest, particularly when it comes to home gardening. The University of Arizona’s Project Harvest, in partnership with the Sonora Environmental Research Institute, Inc., is a multi-year, co-created citizen science project aimed at increasing current understanding of harvested rainwater quality. Citizens in four Arizona, USA, communities (Hayden/Winkelman, Globe/Miami, Dewey-Humboldt, and Tucson) submitted harvested rainwater samples over 3 years. The harvested rainwater samples were then analyzed using IDEXX Colilert® for total coliforms and E. coli and using Hach PathoScreen™ test for sulfate-reducing bacteria (SRB). This study design allows for the validation of a low-cost, at-home alternative methodology for testing rainwater for bacteria that may indicate fecal contamination. In total, 226 samples were tested using both methodologies, revealing a positive correlation (r=0.245; p<0.002) between total coliform MPN and SRB MPN, but no discernable correlation between E. coli MPN and SRB MPN. This work indicates a potential value of SRB testing for harvested rainwater if cost, laboratory access, and fecal contamination are of concern.

Seasonal effect on the prevalence of virulence genes of non-O157 Verotoxic E.coli serogroups in faeces of cattle calves

Calves faecal samples (n=216) were investigated to observe the effect of seasons on the prevalence of serogroups and virulence genes of non-O157 VTEC. A total of 177 (81.94%) E. coli were isolated and 32 (14.81%) were identified as VTEC and serotyping resulted in 13 different non-O157 ‘O’ serogroups. The prevalence of serogroups and their virulence genes was found to be influenced by seasons and highest number were shed in summer (22.22%) followed by rainy (13.88%) and winter season (8.33%), respectively. A higher prevalence of O9 and O11 serogroups (25% each) was observed in summers. Molecular detection of virulence genes revealed the overall prevalence of vt1 to be 37.5%, vt2 43.8%, (vt1+vt2) 18.8%, eaeA 21.9% and hlyA 34.4% genes. Dominance of hlyA 50% was observed in summers, whereas vt1 and vt2 were more prevalent during rain (50% each). The study revealed the link between the occurrence of hlyA gene and O9, O11 serogroups in summers as both the serogroups were hlyA gene bearer. This association might be responsible for more VTEC outbreaks in summers. So, faecal contamination of raw milk seems to pose greater threat of non-O157 VTEC outbreak during hotter and humid months.

Model-based prediction of bathing water quality in a lake polluted by fecal coliform bacteria from combined sewer overflows

In the European Union, recreational water quality is regulated by the bathing water directive, which requires authorities to regularly take water samples to identify fecal bacterial pollution, which can compromise the bathing water quality at designated recreational bathing water areas. Using a case study from Lake Knudsøin Denmark, this paper shows that the bathing water quality occasionally is compromised by overflows from combined sewer systems. Due to the randomness in the frequency of overflow occurrences, the entailing decrease in bathing water quality is not normally detected by the regulatory sampling campaigns. By dedicated sampling campaigns conducted in this project in the proximity of outlets and recreational bathing areas and by hydrodynamical transport modeling, it is shown that the transport patterns of pollutants are crucially and rapidly dependent on dynamic conditions. The occasional short-term pollution by fecal bacteria and consequent decrease in bathing water quality are, therefore, challenging to capture (both spatially and temporally) by regular water sampling. Rather than increasing the frequency of water sampling, an online model-based warning system for fecal bacteria contamination in bathing areas is proposed. This warning system framework includes: (1) dynamical modeling of combined sewer overflow based on rainfall over a catchment area, (2) a hydrodynamical model that simulates current fields in multiple vertical layers based on wind forcing and water fluxes, and (3) a particle dispersion model which provides an estimate of pollutant concentrations. The output from the model has shown potential to issue bathing prohibition if there is a risk of fecal bacteria concentrations below the criteria for good bathing water quality.

Comparison of adsorption-extraction (AE) workflows for improved measurements of viral and bacterial nucleic acid in untreated wastewater

The lack of standardized methods and large differences in virus concentration and extraction workflows have hampered Severe Acute Respiratory Syndrome (SARS-CoV-2) wastewater surveillance and data reporting practices. Numerous studies have shown that adsorption-extraction (AE) method holds promise, yet several uncertainties remain regarding the optimal AE workflow. Several procedural components may influence the recovered concentrations of target nucleic acid, including membrane types, homogenization instruments, speed and duration, and lysis buffer. In this study, 42 different AE workflows that varied these components were compared to determine the optimal workflow by quantifying endogenous SARS-CoV-2, human adenovirus 40/41 (HAdV 40/41), and a bacterial marker gene of fecal contamination (Bacteroides HF183). Our findings suggest that the workflow chosen had a significant impact on SARS-CoV-2 concentrations, whereas it had minimal impact on HF183 and no effect on HAdV 40/41 concentrations. When comparing individual components in a workflow, such as membrane type (MF-Millipore™ 0.45 μm MCE vs. Isopore™ 0.40 μm), we found that they had no impact on SARS-CoV-2, HAdV 40/41, and HF183 concentrations. This suggests that at least some consumables and equipment are interchangeable. Buffer PM1 + TRIzol-based workflows yielded higher concentrations of SARS-CoV-2 than other workflows. HF183 concentrations were higher in workflows without chloroform. Similarly, higher homogenization speeds (5000–10,000 rpm) led to increased concentrations of SARS-CoV-2 and HF183 but had no effect on HAdV 40/41. Our findings indicate that minor enhancements to the AE workflow can improve the recovery of viruses and bacteria from the wastewater, leading to improved outcomes from wastewater surveillance efforts.

Causes of Post-Mortem Carcass and Organ Condemnations and Economic Loss Assessment in a Cattle Slaughterhouse.

The study was undertaken to investigate the main causes of carcass and organ condemnations, as well as to estimate the financial losses suffered by a cattle slaughterhouse. In this regard, an active abattoir survey, based on standard post-mortem inspection procedures for meat, was conducted on 151,741 cattle, from January 2021 to December 2022. Overall, 13.27% (n = 20,125) of the carcasses expressed lesions or pathological conditions and, out of them, 1.15% (n = 1738) were totally confiscated, while another 12.12% (n = 18,387) were partially admitted for human consumption. In the case of organs, the general inspection data reveal that 12.28% (n = 18,630), 7.56% (n = 11,477), 1.89% (n = 2862), and 0.27% (n = 412) of the examined liver, lung, heart, and kidney specimens presented one or more types of abnormalities. In addition, regarding the types of specific pathological findings, dystrophies/anomalies (69.8%), circulatory disorders (40.6%), fecal contamination (60.9%), and suspected bacterial/viral infections showed a dominant occurrence in the liver, lung, heart, and kidneys, respectively. Consequently, the total direct financial losses resulting from edible part condemnation over the two years was estimated at EUR 4,021,717.3, which represents 1.17% of the total achievable net revenue without carcass and organ condemnation. Of this, EUR 3,661,400.4 (1.07%) and EUR 360,316.9 (8.73%) was related to carcass and organ condemnation, respectively. The study results demonstrate that the post-mortem inspection of meat at the slaughterhouse level plays a crucial role in identifying pathological lesions, in addition to some other issues, such as fecal contamination or non-compliant laboratory results, relevant to both public health and economic factors.

Escherichia coli as Microbiological Quality Water Indicator:A High Importance for Human and Animal Health

The purpose of this review is to demonstrate the importance of monitoring microbiological quality in water for animals and humans, which relies primarily on coliforms, mostly Escherichia coli. Fecal coliforms, such as E. coli, are more specific indicators of fecal pollution. A fecal contamination detection can be performed not just in drinking water, but also in the environment. As a result of improved detection methods for E. coli, drinking water is becoming more reliable as a result of the use of E. coli as an indicator of fecal pollution. Drinking water contamination by feces is currently best detected by E. coli. Accordingly, temperate environments are more likely to have fecal coliforms than tropical environments, human and animal feces have high levels of E. coli in comparison to other fecal coliforms, and E. coli detection methods are more affordable, fast, sensitive, specific, and easy to use than other fecal coliforms.

Tracking the sources of Leptospira and nutrient flows in two urban watersheds of Puerto Rico.

This study investigated the relationship between nutrient levels, source of fecal contamination, and pathogenic Leptospira in Puerto Rico's northern coast and San Juan Bay Estuary (SJBE) aquatic ecosystems. Microbial source tracking (MST) was also used to investigate the connections between sources of feces contamination and the presence of Leptospira. Eighty-seven water samples were collected during the June (n=44) and August (n=43) in 2020. To quantify phosphorus and nitrogen concentrations, standard USEPA protocols were utilized, specifically Methods 365.4 for total and dissolved phosphorus, 351.2 for total Kjeldahl nitrogen and ammonium, and 353.2 for nitrate. Lipl32 gene-specific quantitative polymerase chain reaction (qPCR) was used to detect the presence of Leptospira. Human (HF183), canine (BacCan-UCD), and equine (HoF597) MST assays were utilized to trace the origins of fecal contamination. Forty one percent of the locations exceeded Puerto Rico's authorized total phosphorus limit of 160 g L-1, while 34% exceeded the total nitrogen limit of 1700 g L-1. Nearly half of the streams examined are affected by eutrophication. The MST analysis identified human and canine feces as the most prevalent contaminants, affecting approximately 50% of the sites. In addition, Leptospira was detected in 32% of the June samples. There was a significant correlation (r = 0.79) between the incidence of pathogenic Leptospira and the human bacterial marker (HF183). This study illuminates the central role of anthropogenic inputs in nutrient enrichment and pathogen proliferation in Puerto Rico's aquatic ecosystems.

Prevalence and quantitative assessment of foodborne viruses on the imported mussels in Polish market

The aim of this study was an assessment of the prevalence of human enteric viruses such as norovirus (NoV) and hepatitis A and E virus (HAV, HEV) in mussels sold on the Polish market. In addition, the presence of human (hAdV) and swine (pAdV) adenoviruses as indicators of faecal contamination of shellfish was also studied. In total, 246 shellfish samples representing 41 batches of blue and Mediterranean mussels were purchased from Polish seafood wholesalers. Shellfish were processed according to the method in ISO 15216-2:2019 followed by isolation of viral nucleic acids using NucliSens®Magnetic Extraction Reagents (bioMérieux). For virus detection several duplex real-time PCR protocols with incorporated internal amplification controls (IAC) were used. The presence of human enteric viruses was shown in 42 shellfish samples (17.1%). The most frequently detected were NoV (41 samples; 16.7%) followed by HEV (1 sample; 0.4%). None of the samples was positive for HAV, hAdV or pAdV. 15 shellfish batches (36.6%) were virus positive. By the use of Bayesian inference, a true seasonal and country related virus prevalence in shellfish was estimated. NoV GI was more frequently detected in Dutch mussels (18.9%; 95% CI: 6.7%–34.0%), while NoV GII was more frequent in Danish mussels (17.1%; 95% CI: 5.8%–32.5%). However significant differences in virus prevalence in individual and shellfish batches between producing countries were not shown. A seasonal virus distribution pattern in shellfish samples was observed. Lower level of NoV contamination was found in mussels harvested during spring-summer (0.0%–1.3%, 95% CI: 0.1%–4.8%) compared to the fall-winter season (13.0%–20.7%, 95% CI: 6.1%–31.2%). For shellfish batches, a similar seasonal correlation was only observed for NoV GII. The monitoring of marketed shellfish would be an essential tool allowing a reduction of the number of viral food-borne outbreaks.

Public Health Risks and External Food Safety in the Canadian Marketplace

The expansion of the food industry has increased the demand for diverse food products, which poses new challenges to food safety. The production, transportation, and handling of food products from various sources and countries can increase the likelihood of foodborne illness outbreaks and product contamination. Regulatory developments, such as the Hazard Analysis and Critical Control Points (HACCP) systems, have helped mitigate trade barriers and ensure a safe food supply chain. However, different food safety regulations and standards in importing countries can make it challenging to determine if imported goods are as safe as domestically produced ones. Total coliform testing is a commonly used indicator of potential fecal contamination in food products. Thus, this study aims to provide a comparative analysis between a domestic and an international pasteurized dairy product falling under category 3 to provide literature and the means to mitigate safety risks.

Fresh produce as a reservoir of antimicrobial resistance genes: A case study of Switzerland

Antimicrobial resistance (AMR) can be transferred to humans through food and fresh produce can be an ideal vector as it is often consumed raw or minimally processed. The production environment of fresh produce and the agricultural practices and regulations can vary substantially worldwide, and consequently, the contamination sources of AMR. In this study, 75 imported and 75 non-imported fresh produce samples purchased from Swiss retailers were tested for the presence of antimicrobial resistant bacteria (ARB) and antimicrobial resistance genes (ARGs). Moreover, the plasmidome of 4 selected samples was sequenced to have an insight on the diversity of mobile resistome. In total, 91 ARB were isolated from fresh produce, mainly cephalosporin-resistant Enterobacterales (n = 64) and carbapenem-resistant P. aeruginosa (n = 13). All P. aeruginosa, as well as 16 Enterobacterales' isolates were multidrug-resistant. No differences between imported and Swiss fresh produce were found regarding the number of ARB. In 95 % of samples at least one ARG was detected, being the most frequent sul1, blaTEM, and ermB. Abundance of sul1 and intI1 correlated strongly with the total amount of ARGs, suggesting they could be good indicators for AMR in fresh produce. Furthermore, sul1 correlated with the fecal marker yccT, indicating that fecal contamination could be one of the sources of AMR. The gene sulI was significantly higher in most imported samples, suggesting higher anthropogenic contamination in the food production chain of imported produce. The analyses of the plasmidome of coriander and carrot samples revealed the presence of several ARGs as well as genes conferring resistance to antiseptics and disinfectants in mobile genetic elements. Overall, this study demonstrated that fresh produce contributes to the dissemination of ARGs and ARB.

The host specificity of pilus gene traA in Escherichia coli and its use in tracking human fecal pollution

A reliable and accurate fecal source tracking (FST) approach is important in water quality management and preventing foodborne and waterborne diseases. In this study, a genetic marker of Escherichia coli (E. coli) was identified and utilized to differentiate between human and animal sources of fecal contamination. Nucleotide polymorphisms of 14 genes coding for cellular surface proteins, mainly fimbriae, were analyzed using the 22 draft genomes of E. coli strains from human and three domestic animal sources in Japan. A signature sequence, traAh, within the pilin gene traA, was found to be highly associated with E. coli of human origin. Subsequently, an end-point polymerase chain reaction (PCR) assay, namely PCR-Htra, was developed, specifically targeting traAh. The high association between traAh and E. coli of human origin was validated through the PCR-Htra amplification. This encompassed 1045 E. coli strains isolated from surface water, human feces or sewages, and feces from 12 animal species, including domestic and wild animals in the states of Missouri and Virginia in the United States of America (USA). The data suggested that the sensitivity and specificity of PCR-Htra assay were 49.0 % and 99.5 % respectively in distinguishing human-origin E. coli from nonhuman-source ones. Furthermore, the result of our in silico analysis of GenBank® data suggests that traAh may have a global distribution as the sequence was found in human-origin E. coli isolated from at least 14 countries around the world. Thus, the PCR-Htra may provide a new FST tool for rapid and accurate detection of human-origin E. coli, serving as a means to identify human fecal contamination in water.

Fecal bacteria contamination in the Adriatic Sea: Investigating environmental factors and modeling to manage recreational coastal waters

This study is based on assessing fecal indicator bacteria contamination along meteorological, hydrological and physical-chemical variables after high rainy events during the summer period. The study focused on four different coastal sites in the western and eastern Adriatic coast characterized by various geomorphological and hydrological features, levels of urbanization and anthropogenic pressures, with the aim of finding appropriate and effective solutions to ensure the safety and sustainability of tourism and public health. Detailed in-situ survey revealed a wide range of fecal indicator bacterial (FIB) across the different river mouths with concentrations of E. coli ranging from 165 to 6700 CFU 100 mL−1. It was found that nitrogen compounds track microbial load and acted as tracers for fecal contaminants. Further, a modelling tool was also used to analyze the spatial and temporal distribution of fecal pollution at these coastal sites. The integrated monitoring through high frequent survey in river waters and modeling framework allowed for the estimation of fecal indicator bacterial load at the river mouth and examination of fecal pollutant dispersion in recreational waters, considering different scenarios of fecal dispersion along the coast. This study formed the basis of a robust decision support system aimed at improving the management of recreational areas and ensuring the protection of water bodies through efficient management of bathing areas.

Selection of a diagnostic tool for microbial water quality monitoring and management of faecal contamination of water sources in rural communities

The aim of the current study was to evaluate, validate and select microbial water quality monitoring tools to establish their suitability and feasibility for use in rural communities. The monitoring of water quality was performed at three different levels: i) basic level focusing on sanitary inspection and hydrogen sulphide (H2S) test; ii) intermediate level via enumeration of faecal indicator bacteria (faecal coliforms, Escherichia coli, Enterococcus spp. and Clostridium perfringens); and iii) advanced level based on qPCR detecting host-associated genetic markers (BacHum, BacCow, Cytb, Pig-2-Bac, and BacCan) and pathogens (Vibrio cholerae, Escherichia coli O157:H7, and Shiga toxin-producing Escherichia coli). A positive correlation was recorded between sanitary risk and faecal coliforms (r = 0.613 and p < 0.002), E. coli (r = 0.589 and p < 0.003), and Enterococcus spp. (r = 0.625 and p < 0.003). The H2S test showed positive correlations with sanitary risk score (r = 0.623; p < 0.003), faecal coliforms (r = 0.809; p < 0.001), E. coli (r = 0.779; p < 0.001) and Enterococcus spp. (r = 0.799; p < 0.001). Similar correlation patterns were also found with advanced techniques used for detecting host-associated genetic markers, excepted between Clostridium perfringens, and Pig-2-Bac (pig), BacCan (dog), and V. cholerae. The H2S test and sanitary inspections are therefore suitable and cost-effective tools to capacitate rural areas at household level for the monitoring of faecal contamination and management of water sources.

Water Quality Assessment on Physicochemical and Biological Parameters of Selected Lentic Ecosystem in Aboh Mbaise Local Government Area, Imo State, Nigeria

The aim of this study is to determine the suitability of the ponds in Aboh Mbaise Local Government Area, Imo State, Nigeria for domestic use. A cross-sectional study was carried out for the study. Composite sampling method was used, where three water samples were collected randomly from each station to ensure that the samples were representative of the entire station. Samples were collected during the rainy season, given that the ponds always dry up during the dry season. Physicochemical and microbial analyses were carried out on water samples of selected lentic aquatic ecosystems in randomly identified ponds in five communities of Aboh Mbaise. These ponds are used by the residents of these villages for various domestic and anthropogenic activities. Statistical analyses include: descriptive statistics, Analysis of Variance, Parallel coordinate plot, Pearson correlation, Agglomerative Hierarchical Clustering (AHC) and Water Quality Index (WQI) were carried out. Results indicate that pond water within the study area did not fall within the bracket of good water quality, as per the WQI range of 0 to 50, thereby affirming the poor quality of water. The WQI for the five ponds ranges from 1338.71 - 3322.81. There is a direct correlation between the presence of Total Bacterial Counts from Shigella and Salmonella counts and the presence of fecal contamination from both human and animal wastes. Given the poor quality of the pond water, it is unhealthy for the inhabitants in the study area to use pond water for food preparation and other household tasks, except if it is treated.

A simple and rapid method for detecting fecal pollution in urban rivers by measuring the intrinsic β-D-glucuronidase activity of Escherichia coli

As urban rivers are domestic, industrial, and agricultural water resources, fecal pollution poses human health and environmental risks. In this study, we developed a simple and rapid method to detect fecal pollution in urban rivers. Water samples were mixed with liquid medium, including a fluorescent substrate and fluorescence intensity (F.I.) was measured using a microplate reader to determine Escherichia coli (E. coli) β-D-glucuronidase (GUS) activity instead of E. coli concentration. GUS activities measurements in pure E. coli cultures revealed that E. coli incubated with a GUS substrate accumulated GUS enzymes in their cells, whereas those incubated without a GUS substrate did not. The increase in GUS activity corresponded to the proliferation of E. coli and the GUS activity increased linearly even during the lag growth phase of E. coli, indicating the presence of intrinsic GUS (iGUS) in E. coli cells before incubation. iGUS activity persisted at 81 % in the chlorinated samples, even though the E. coli concentration was reduced by a factor of 106. The iGUS activity persisted for approximately three days. Therefore, we assumed that E. coli present in fecal contaminants, in which GUS substrates are present, could be distinguished from those surviving in the natural environment for three days or longer by measuring iGUS activity. River water samples were collected upstream and downstream of the discharge outlets of municipal wastewater treatment plants and a combined sewer outlet. The iGUS activities were <0.24 mMFU/mL for the upstream samples and >0.21 mMFU/mL for the downstream samples. Interestingly, E. coli concentrations were not necessarily associated with fecal pollution. This indicates that by setting a threshold for iGUS activity, our method can be used as a simple and rapid method for detecting fecal pollution in urban rivers. Because the limit of detection for our method is 20 CFU/mL, our method is applicable to detecting high fecal pollution in a small river.

Evaluation of karst spring water quality in northeast Tennessee using water quality indices

AbstractEnsuring access to safe drinking water to protect public health in communities underserved or unserved by centralized water systems requires regular water quality testing and reporting. However, households depending on unregulated water systems like wells and springs, which are less routinely tested, may be unaware of their water quality. Access to easy‐to‐comprehend water quality information may be challenging. Therefore, this study utilized multiple water quality parameters to determine karst spring water quality using two water quality index (WQI) methods. This approach aggregates and summarizes water quality data into a single value or index characterizing the general health status of water at a given location in an easy‐to‐understand way. In situ measurements of physicochemical parameters (pH, dissolved oxygen, temperature, turbidity, conductivity, specific conductance, total dissolved solids, and oxidation–reduction potential) were taken at 50 karst springs in east Tennessee during summer 2021. Water samples were analyzed for microbial (fecal coliform and Escherichia coli), nutrients (nitrate and nitrite), and radiological (radon) constituents using standard analytical methods. WQI method 1 (Brown et al. Water Quality Index) rated 12% of springs as “very poor” water quality and 88% as “unfit for drinking.” WQI method 2 (National Sanitation Foundation Water Quality Index) rated 4% of the sampled springs as “good,” 92% as “moderate,” and 4% as “bad.” Given the prevalence of fecal contamination in the sampled springs, even springs rated good should be properly treated before consumption. Overall, these findings demonstrate the importance of selecting appropriate WQI for the end water use, and for water quality information that is easily understandable by water users.

Perioperative Adverse Outcome and Its Predictors After Emergency Laparotomy Among Sigmoid Volvulus Patients: Retrospective Follow-Up Study.

Acute sigmoid volvulus is a surgical emergency with closed-loop obstruction of the colon that often requires emergency laparotomy, which is associated with a multitude of post-operative complications. Although sigmoid volvulus is the main cause of intestinal obstruction in Ethiopia, local studies of its management outcomes are limited. To assess the magnitude and predictors of adverse perioperative outcomes of emergency laparotomy for acute sigmoid volvulus in the Debre Markos Comprehensive Specialized Hospital (DMCSH), Amhara region, Ethiopia in 2023. This was a retrospective follow-up study. Descriptive statistics were used to measure perioperative outcomes and other study variables. Bivariable and multivariable logistic regression models were used to identify the predictors of adverse surgical outcomes. Associations were considered significant at p < 0.05 (95% confidence interval). In total, 170 study participants were enrolled, with a response rate of 91.4%. Forty-nine patients (28.8%) developed perioperative adverse outcomes. Pneumonia (29 patients, 28.1%), surgical site infection (19 patients, 18.4%), and wound dehiscence (10 patients, 9.7%) were the most common complications. Pre-operative shock [AOR: 3.87 (95% CI: (1.22, 12.28))], pus or fecal matter contamination of the peritoneum [AOR: 4.43 (95% CI: (1.35, 14.47)], and a higher American Society of Anesthesiologists (ASA) score [AOR: 2.37 (95% CI: (1.05, 5.34))] were identified as predictors of perioperative adverse events. The perioperative adverse outcomes in this study were higher than those reported in Ethiopian national and global reports following emergency laparotomies. Hypotension at presentation, pus and/or fecal matter contamination of the peritoneum, and higher ASA scores are strong predictors of increased perioperative adverse outcomes. Therefore, healthcare providers and institutions involved in the delivery of emergency surgical care should emphasize the importance of early surgical intervention, adequate resuscitation, and patient monitoring to improve perioperative outcomes.