Escherichia coli as a Tool for Disease Risk Assessment of Drinking Water Sources

Identifying predictors of E. coli in rural household water in sub-Saharan Africa using elimination regression

Exposure to fecally contaminated drinking water contributes to the global disease burden, especially in sub-Saharan Africa (SSA). We used cross-sectional data and elimination regression analysis to examine factors influencing E. coli contamination in household drinking water samples from 4,499 rural households in nine countries in SSA (Malawi, Mozambique, and Zambia in Southern Africa; Ghana, Mali, and Niger in Western Africa; and Kenya, Rwanda, and Tanzania in Eastern Africa). The proportion of household water samples containing E. coli was 71%, ranging from 45% (Malawi) to 89% (Tanzania). Pooled and multi-country predictive logistic regression models showed that using an unimproved-type water source, the absence of a community water committee, and domestic animal ownership were significantly associated with household drinking water contamination. Household water treatment and storage practices, sanitation and hygiene practices, and payment for drinking water were not significantly associated with E. coli contamination in any model. The season was a significant predictor of E. coli in the pooled model; samples collected in the rainy season were 2.3 [2.0, 2.7] times as likely to be contaminated with E. coli. Practitioners and policymakers should prioritize implementing piped on-plot water services, establishing effective local water source management structures, and incorporating animal husbandry practices into water, sanitation, and hygiene interventions.

Water disinfection using hydrogen peroxide with fixed bed hematite catalyst - kinetic and activity studies

A lab-scale reactor with a fixed-bed hematite catalyst for the effective decomposition of H2O2 and bacteria inactivation was designed. The bactericidal effect is the largest at a low initial bacterial count of 2·103 CFU/L, which is typical for natural surface waters. When using a 5 mM H2O2 solution and a residence time of 104 min, the reduction in the number of E. coli bacteria is about 3.5-log. At a higher initial bacterial count of 1-2·104 CFU/L, a 5 mM H2O2 solution reduces the bacteria number by about 4-log. The H2O2 decomposition follows the log-linear kinetics of a first-order reaction while the bacterial inactivation does not. The kinetics of bacterial inactivation was described using the Weibull model in the modified form: log10(N0/N) = b · tn. The values of the non-linearity parameter n were found to be lower than 1, indicating that bacterial inactivation slows down over time. With increasing initial H2O2 concentration, the rate parameter b increases while the non-linearity parameter n decreases. With increasing temperature, both parameters increase. The stability of the catalyst has been proved by XRD, FTIR, SEM, and ICP-OES. The concentration of iron leaching into water during disinfection is much lower than the limit declared by WHO for iron in drinking water. The results show that technical-grade hematite is a promising Fenton-like catalyst for water disinfection. The fixed-bed reactor can be the basis of the mobile installations for water purification in emergencies.

Systematic review and meta-analyses of the role of drinking water sources in the environmental dissemination of antibiotic-resistant Escherichia coli in Africa

Escherichia coli are pathogenic and antibiotic-resistant organisms that can spread to humans through water. However, there is sparse synthesised information on the dissemination of antibiotic-resistant E. coli through drinking water in Africa. This review provides an overview of the environmental spread of antimicrobial-resistant E. coli through drinking water in Africa. We performed a systematic review based on PRISMA guidelines, and 40 eligible studies from 12 countries were identified until June 2023. Four electronic databases (PubMed, Elsevier, AJOL, and DOAJ) were searched. Studies that employed phenotypic tests (n = 24/40) in identifying the bacterium outstripped those that utilised genome-based methods (n = 13). Of the 40 studies, nine and five, respectively, assessed the bacterium for antimicrobial resistance (AMR) phenotype and genotype. Multiple antibiotic resistance indices of 0.04-0.1 revealed a low level of antibiotic resistance. The detection of multidrug-resistant E. coli carrying resistance genes in certain water sources suggests that AMR-surveillance expansion should include drinking water.

Material Breakthroughs in Smart Food Monitoring: Intelligent Packaging and On-Site Testing Technologies for Spoilage and Contamination Detection

Despite extensive commercial and regulatory interventions, food spoilage and contamination continue to impose massive ramifications on human health and the global economy. Recognizing that such issues will be significantly eliminated by the accurate and timely monitoring of food quality markers, smart food sensors have garnered significant interest as platforms for both real-time, in-package food monitoring and on-site commercial testing. In both cases, the sensitivity, stability, and efficiency of the developed sensors are largely informed by underlying material design, driving focus toward the creation of advanced materials optimized for such applications. Herein, a comprehensive review of emerging intelligent materials and sensors developed in this space is provided, through the lens of three key food quality markers - biogenic amines, pH, and pathogenic microbes. Each sensing platform is presented with targeted consideration toward the contributions of the underlying metallic or polymeric substrate to the sensing mechanism and detection performance. Further, the real-world applicability of presented works is considered with respect to their capabilities, regulatory adherence, and commercial potential. Finally, a situational assessment of the current state of intelligent food monitoring technologies is provided, discussing material-centric strategies to address their existing limitations, regulatory concerns, and commercial considerations.

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.

Microbial food safety of lettuce produced under irrigated wastewater from Onyasia River in Ghana

Fresh produce continues to be the main source of foodborne illness outbreaks, particularly in developing countries where water stress results in the use of surface wastewater all year round for irrigation of vegetables. The objective of the current study was to evaluate the microbial quality of lettuce irrigated with wastewater from Onyasia river. Lettuce and soil were sampled from selected vegetable farms on the Eastern gate of the Ghana Atomic Energy Commission land alongside surface wastewater from the Onyasia river, which is used as the main source for irrigation. Samples were analyzed for aerobic mesophilic plate counts, total coliforms count, fecal coliforms count, Salmonella counts and intestinal parasites using standard methods. Surface wastewater was found to be contaminated with mean fecal coliform counts of log 3.50 cfu/100 mL. Enterobacter cloacae, Acinetobacter baumannii, and Klebsiella pneumonia were also isolated from the wastewater samples. No intestinal parasite egg was detected in wastewater samples. While fecal coliforms and Salmonella spp were not detected, mean aerobic mesophilic plate counts (log 4.82 cfu/g) and total coliforms count (log 3.50 cfu/g) were recorded in the lettuce samples. Enterobacter asburiae, Acinetobacter baumannii, Klebsiella variicola and Citrobacter freundii were isolated from lettuce. Infective larvae of helminths were observed on lettuce samples at a density of 36/g-648/g with a mean of 342/g. Soil samples recorded a mean aerobic mesophilic plate counts of log 6.14 cfu/g, total coliforms count of log 4.90 cfu/g while fecal coliforms and Salmonella spp were not detected (<1 cfu/g) Soil samples yielded a mean infective larval count of 1941.5 larvae/g and a Strongyle count of 12 eggs/g. Even though less than 1 cfu/g of Salmonella spp were found, the study found lettuce to be contaminated with other foodborne bacteria pathogens, opportunistic bacteria pathogens, eggs and infective larvae of intestinal parasites of health importance. As a consequence, the microbial food safety risk associated with wastewater irrigated vegetables was observed to be high with possible public health implications. It is recommended that wastewater from the Onyasia River should be treated before use for irrigation of lettuce.

Microwave disinfection strengthened by a biochar-based microwave absorbing material for sewage resource utilization

Proper disinfection treatment is the basic guarantee for safe utilisation of sewage. However, the commonly used disinfection methods are not suitable for nutrients containing reclaimed water. In this work, the microwave disinfection method assisted by a microwave-absorbing material in recycled water samples was investigated. Magnetic corn stalk biochar (MCSB), the microwave absorbing material, was prepared by high temperature carbonisation of corn stalk particles impregnated with ferrous sulfate. Escherichia coli and fecal coliforms were selected as target microorganisms to investigate the disinfection efficiency of MCSB assisted microwave radiation (MW/MCSB). The addition of microwave absorbing materials significantly improves the disinfection effect of water samples. Compared with the microwave radiation (MW) without MCSB, the bactericidal rate by using 107 CFU/L E. coli suspension increased from 63.5% to 100% at 480 W for 30 s after adding 4 g/L MCSB. Besides, the effects of MCSB dosage, microwave power, microwave radiation time, and initial bacterial concentration on disinfection efficiency were explored. Moreover, the bactericidal efficiency for actual sewage samples was also demonstrated by treating the effluent from septic tank sewage. The residual fecal coliforms in treated water samples met China's farmland irrigation water standard (GB 5084-2021). The result indicates that the proposed method of microwave disinfection strengthened by MCSB has a promising application prospect for reclaimed water disinfection.

Sources, pollution, and ecological risk assessment of polycyclic aromatic hydrocarbons (PAHs) in Porto-Novo Lagoon, Benin Republic

The Porto-Novo Lagoon is influenced by agricultural discharges and human activities. In order to evaluate the impact of wastes and human activities on Porto-Novo Lagoon, the sources and ecological risks of sixteen polycyclic aromatic hydrocarbons (PAHs) were assessed. The physicochemical and biological parameters of the water were also determined. The result showed that between the sampling sites, the mean concentration of dissolved oxygen ranged from 4.8 ± 0.5 to 5.1 ± 0.2 mg/L; biochemical oxygen demand varied from 12.6 ± 2.0 to 77.9 ± 81.9 mg/L; biological oxygen demand ranged from 2.8 ± 2.6 to 5.6 ± 0.9 mg/L; total phosphorus varied between 4.7 ± 2.7 and 15.3 ± 9.5 mg/L; total dissolved solids ranged from 183.0 ± 115.8 to 337.5 ± 413.3 mg/L, and Escherichia coli varied from 495.0 ± 542.9 to 1920.0 ± 2676.5 UFC/100 mL. Water parameter values obtained were not within World Health Organization (WHO)-recommended limits except pH and TDS. Total PAHs (∑PAHs) concentration varied from 38.8 to 123.9 mg/L. The mean ∑PAH concentration was 83.2 ± 20.3 mg/L. Benzo[b]fluoranthene, benzo[g,h,i]perylene, and benzo[k]fluoranthene were the most dominant PAHs and contributed to 55.9%, 15.3%, and 4.5% of the ∑PAHs concentration, respectively. Douane-Tokpa and Djassin recorded the lowest and highest concentrations. PAHs of four to six rings were the most abundant across the sampling sites. Naphthalene showed the lowest risk in the lagoon. Acenaphthene showed low risk at Djassin, while Indeno(1,2,3 cd)pyrene showed low risk at Benin Industry Body Fat. Except for those that were not detected, all the PAHs at individual or complex mixture levels showed high risk at all the sites. The highest total concentration was recorded in Djassin followed by Beaurivage. The high level of PAHs pollution was attributed to both human and goods traffic, runoff, and the complex hotels close to the lagoon. Molecular diagnostic ratios and principal component analysis suggest that the target hydrocarbons were from both petrogenic and pyrogenic sources with predomination of vehicular emission and coal/woods combustion. ∑LWM/HWM confirmed also the predominance of pyrolytic sources of PAHs in Porto-Novo Lagoon. The predominance of the vehicular emission may be due to the position of the complex Porto-Novo Lagoon-Nokoué Lake which is between the two big cities of the country.

Antibiotic-Resistant Bacteria and Resistance Genes in Isolates from Ghanaian Drinking Water Sources

The control of infectious diseases is seriously threatened by the increase in the number of microorganisms resistant to antimicrobial agents. Antibiotic-resistant bacteria have also been identified in the water environment. A field study was performed sampling drinking water sources in seven districts of southern Ghana targeting boreholes, dams, hand-dug wells, and streams during baseflow conditions. Bacteria were isolated (N = 110) from a total of 67 water samples to investigate their antimicrobial susceptibility and to determine their carriage of select antibiotic resistance genes. Bacterial identification was performed using conventional selective media methods and the analytical profile index (API) method. Antibiotic susceptibility tests were carried out using the Kirby–Bauer method. Results indicated that all water sources tested were of poor quality based on the presence of fecal indicator organisms. The most commonly occurring bacterium isolated from water was Klebsiella spp. (N = 24, 21.8%), followed by E. coli (N = 23, 20.9%). Gram-negative bacteria isolates were most commonly resistant to cefuroxime (24.5%), while the Gram-positives were most commonly resistant to meropenem (21.3%). The highest rates of bacterial resistances to more than one antibiotic were observed in Klebsiella spp. (30.0%) followed by E. coli (27.8%). PCR was used to detect the presence of a select antibiotic resistance genes in the Gram-negative isolates. The presence of bla_NDM-1, sull, tet(O), and tet(W) were observed in isolates from all water sources. In contrast, ermF was not detected in any of the Gram-negative isolates from any water source. Most (28.7%) of the resistance genes were observed in E. coli isolates. Reducing microbial contamination of the various water sources is needed to protect public health and to ensure the sustainability of this resource. This further calls for education of the citizenry.

Draft Genome Sequences of Multidrug-Resistant Escherichia coli Strains Isolated from River Water in Malaysia

Antimicrobial resistance has become a primary concern in clinical and public health. Escherichia coli is one of the bacteria that carries and disseminates antimicrobial resistance genes to the community. Here, we report the draft genome sequence of three multidrug-resistant E. coli strains that were isolated from river water in Malaysia.

Universal Enzyme-Based Field Workflow for Rapid and Sensitive Quantification of Water Pathogens

A universal filtration and enzyme-based workflow has been established to allow for the rapid and sensitive quantification of leading pathogens Cryptosporidium parvum, Giardia gamblia, Campylobacter jejuni, and Escherichia coli from tap water samples with volumes up to 100 mL, and the potential to scale up to larger volumes. qPCR limits of quantification as low as four oocysts for Cryptosporidium, twelve cysts for Giardia, two cells for C. jejuni, and nineteen cells for E. coli per reaction were achieved. A polycarbonate filter-based sampling method coupled with the prepGEM enzyme-based DNA extraction system created a single-step transfer workflow that required as little as 20 min of incubation time and a 100 µL reaction mix. The quantification via qPCR was performed directly on the prepGEM extract, bypassing time-consuming, labour-intensive conventional culture-based methods. The tap water samples were shown to contain insoluble particles that inhibited detection by reducing the quantification efficiency of a representative pathogen (C. jejuni) to 30-60%. This sample inhibition was effectively removed by an on-filter treatment of 20% (v/v) phosphoric acid wash. Overall, the established workflow was able to achieve quantification efficiencies of 92% and higher for all four leading water pathogens, forming the basis of a rapid, portable, and low-cost solution to water monitoring.

Design and assembly of a domestic water temperature, pH and turbidity monitoring system

Objective

The aim of this study was to design a domestic water temperature, pH and turbidity monitoring system that could constantly log temperature, pH and turbidity of water and give alerts in case the parameters are outside the acceptable limits for potable water.

Results

The system was designed, assembled and performed as expected. The study indicates that the proposed and designed system outperforms the existing manual monitoring system as it can constantly track and store changes in water quality. This could be used to prepare better treatment processes as well as identify problems in the water distribution system early enough.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-021-05578-9.