Waterborne Pathogenic Bacteria Research Articles

HPB-Chip: An accurate high-throughput qPCR-based tool for rapidly profiling waterborne human pathogenic bacteria in the environment

Waterborne pathogens are threatening public health globally, but profiling multiple human pathogenic bacteria (HPBs) in various polluted environments is still a challenge due to the absence of rapid, high-throughput and accurate quantification tools. This work developed a novel chip, termed the HPB-Chip, based on high-throughput quantitative polymerase chain reactions (HT-qPCR). The HPB-Chip with 33-nL reaction volume could simultaneously complete 10,752 amplification reactions, quantifying 27 HPBs in up to 192 samples with two technical replicates (including those for generating standard curves). Specific positive bands of target genes across different species and single peak melting curves demonstrated high specificity of the HPB-Chip. The mixed plasmid serial dilution test validated its high sensitivity with the limit of quantification (LoD) of averaged 82 copies per reaction for 25 target genes. PCR amplification efficiencies and R2 coefficients of standard curves of the HPB-Chip averaged 101 % and 0.996, respectively. Moreover, a strong positive correlation (Pearson’ r: 0.961–0.994, P < 0.001) of HPB concentrations (log10 copies/L) between HPB-Chip and conventional qPCR demonstrated high accuracy of the HPB-Chip. Subsequently, the HPB-Chip has been successfully applied to absolutely quantify 27 HPBs in municipal and hospital wastewater treatment plants (WWTPs) after PMA treatment. A total of 17 HPBs were detected in the 6 full-scale WWTPs, with an additional 19 in the hospital WWTP. Remarkably, Acinetobacter baumannii, Legionella pneumophila, and Arcobacter butzler were present in the final effluent of each municipal WWTP. Overall, the HPB-Chip is an efficient and accurate high-throughput quantification tool to comprehensively and rapidly quantify 27 HPBs in the environment.

Effect of dissolved organic matter on the inactivation of bacteriophage MS2 by graphitic carbon nitride - based photocatalysis

Waterborne pathogenic bacteria and viruses are of great concern to environmental and public health. This study focused on the impact of dissolved organic matter (DOM) on photocatalytic inactivation of bacteriophage MS2 by utilizing a visible-light-responded photocatalyst composed of rGO-supported g-C3N4 (7.5%GCN). The results showed that the inactivation rate of MS2 by 7.5%GCN photocatalysis was 3.20 log at λ > 400 nm and 3.27 log at λ > 305 nm within 120 min. The presence of humic acid (HA) in the water matrix led to a decline in the inactivation rate of 2.19 log at λ > 400 nm and 2.08 log at λ > 305 nm, representing a reduction of 31.56% and 36.4%. During an 8 h inactivation process in ultrapure water using 7.5%GCN photocatalysis under λ > 400 nm, steady-state concentrations of 1O2, •OH, •O2- and H2O2 were measured to be 5.67 × 10-13, 8.56 × 10-7, 1.21 × 10-5 and 7.08 × 10-5 mol/L, respectively; When in presence of HA, the concentrations of ROSs were inhibited except for 1O2. The order of ROS steady-state concentration was found to be H2O2 > •O2-> •OH> 1O2 during 7.5%GCN photocatalysis, both within and without HA. Transmission electron microscopy (TEM) analysis revealed that the distortion in the morphology of MS2, potentially leading to the disclosure of RNA. Furthermore, protein analysis indicated that the protein structure was damaged, resulting in a decrease of approximately 90% in its concentration. This study may shed light on the impact of DOM during solar light-driven photocatalysis, offering a green, environment-friendly, and sustainable water treatment process.

Mitigation of T3SS-mediated virulence in waterborne pathogenic bacteria by multi-electrode cylindrical-DBD plasma-generated nitric oxide water

S. enterica, S. flexneri, and V. parahaemolyticus bacteria are globally recognized to cause severe diarrheal diseases, consisting of Type III Secretion System (T3SS) effectors that help in bacterial infection and virulence in host cells. This study investigates the properties of multi-electrode cylindrical DBD plasma-generated nitric oxide water (MCDBD-PG-NOW) treatment on the survival and virulence of S. enterica, S. flexneri, and V. parahaemolyticus bacteria. The Colony Forming Unit (CFU) assay, live/dead cell staining, lipid peroxidation assay, and bacteria morphological analysis showed substantial growth inhibition of bacteria. Moreover, to confirm the interaction of reactive nitrogen species (RNS) with bacterial membrane biotin switch assay, DAF-FM, and FTIR analysis were carried out, which established the formation of S-nitrosothiols in the cell membrane, intracellular accumulation of RNS, and changes in the cell composition post-PG-NOW treatment. Furthermore, the conventional culture-based method and a quantitative PCR using propidium monoazide showed minimal VBNC induction under similar condition. The efficiency of bacteria to adhere to mammalian colon cells was significantly reduced. In addition, the infection rate was also controlled by disrupting the virulent genes, leading to the collapse of the infection mechanism. This study provides insights into whether RNS generated from PG-NOW might be beneficial for preventing diarrheal infections.

Computational study of antiviral, anti-bacterial, and anticancer activity of green-extracted Sidr (Ziziphus spina-Christi) fruit phenolics

Background: Hepatitis may result in inflammation, swelling, cirrhosis, cancer, and failure. Food-born bacteria like Escherichia coli, Staphylococcus aureus, Vibrio cholera, and Helicobacter pylori have widely developed antibiotic resistance in recent years. The latter is a common hazardous pathogen that may lead to stomach vacuoles and gastric cancer. Despite the toxicity, medication resistance, and/ or financial burdens of conventional cancer medicines, most breast cancer patients globally develop recurrence or relapse distant metastases in many other organs after receiving initial common treatment. Such cases need to find solutions that differ from conventional medicines. Plants are an essential source of efficient bioactive compounds that could be utilized in fighting bacterial and viral infections and/or cancer safely. Due to their capability to control many molecular pathways with less harmful effects, the phytochemicals used in complementary medicine have recently attracted more attention. Most of these phytochemicals are members of one of the alkaloids, phenolics, carotenoids, flavonoids, and/ or terpenoids groups. Sidr (Ziziphus spina-Christi (L.) Willd) is a well-known, traditionally used fruit for curing many diseases in the Middle East. Network medicine and AI technologies can rapidly hasten the discovery of new drug alternatives. Objective: This study aimed to extract phenolic compounds from Sidr via two green chemistry approaches, then to predict the anticancer and the antimicrobial effect of the characterized phytochemicals towards certain microorganisms. Methods: Sidr fruit powder was extracted via supercritical CO2 and ethanol asco-solvent and the defatted residues were extracted via the hydro-ethanolic ultrasound assisted extraction to obtain a higher yield of phenolic compounds. The phenolic compounds were characterized and computationally studied for their biological activity against different protein targets of hepatitis virus, food- and water-borne pathogenic bacteria, and breast cancer via Molecular docking and Molecular Dynamics. Additionally, ADMET study was performed for the compounds with high Vina score and good dynamics results. Results: Chemical analysis revealed the presence of seven different phenolic compounds (Gallic acid, caffeic acid, Pyrocatechol, Coumaric acid, Ferulic acid, Quercetin, and Cinnamic acid). By the results obtained from molecular docking phytochemical Quercetin showed good binding scores and interactions with S. aureus tyrosyl-tRNA synthetase (1JIJ), V. cholera UDP-N-acetylenolpyruvoylglucosamine reductase (3I99), Human topoisomerase Ⅱ beta (3QX3) and H. pylori shikimate kinase (3N2E) with Vina scores equal -9.9, -9.4, -9.3 and -8.5 respectively. ADMET analysis showed that Quercetin obeyed Lipinski's rule and had high GI absorbance, no BBB, and low toxicity within limits. Molecular dynamics studies revealed that V. cholera (3I99), Human topoisomerase Ⅱ beta (3QX3), and H. pylori shikimate kinase (3N2E) proteins don't show effective stabilities, and more fluctuations were observed. Quercetin with S. aureus tyrosyl-tRNA synthetase (1JIJ) showed good stability and formed a stable complex with good RMSD and RMSF. Conclusion: Based on the results obtained, the compound Quercetin can be a potent molecule to treat bacterial infections related to the antibiotic-resistant Staphylococcus aureus. Sidr (Ziziphus spina-Christi (L.) Willd) is a widely consumed fruit worldwide and it has been used in traditional medicine since ancient times, so using this plant’s extracts may be a potent anti-bacterial treatment. These results need further in vitro and in vivo studies in the future to prove their accuracy.

Comparison of Two Bacterial Characterization Techniques for the Genomic Analysis of River Microbiomes

This study compares the feasibility of matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry with whole genome sequencing (WGS) for identifying bacteria in river surface water samples. We collected samples from four rivers in the Dominican Republic and used both techniques to characterize bacterial profiles. MALDI-TOF demonstrated high precision, with 86.2% similarity to WGS results, except for a few discordant cases due to database limitations. MALDI-TOF provided cost-effective and rapid identification, making it a promising alternative to WGS in resource-constrained regions. In particular, good effectiveness of MALDI-TOF in identifying bacteria with a high probability of being resistant to antibiotics was observed, which allows this technology to be used in the monitoring processes of this type of microorganism for their rapid, accurate, and low-cost identification. We found this technology to be advantageous for environmental bacterial profiling, with potential applications in understanding waterborne pathogenic bacteria. Our findings underline the relevance of MALDI-TOF in microbiology and its potential to expand its capabilities in bacterial identification and protein profiling.

The risk of bacterial virulence in the face of concentrated river pollution

Abstract The decrease in low-water flows and the increase in water temperature and other parameters as observed in the rivers over the last 50 years suggest that a concentration of compounds and pollutants is taking place, in connection with climate change and/or anthropisation (without discerning their respective contributions). These effects occur in a context where the rivers are already impacted by the presence of many pollutant cocktails (pesticides, drugs, and others). The authors now show that these pollutant cocktails – at the environmental concentrations currently found – constitute a threat to human health through their possible effects on the virulence of pathogenic bacteria. While certain genes of Salmonella Typhimurium may not experience an increased risk, the exposure to more concentrated cocktails (at a five-fold concentration) could potentially amplify certain virulent factors such as the motility of Pseudomonas aeruginosa H103. The findings indicate that pollution mixtures have an effect on the virulence potential of certain waterborne pathogenic bacteria, even at concentrations currently observed in rivers.

The control of waterborne pathogenic bacteria in fresh water using a biologically active filter

The aim of this study was to investigate the control of three species of bacteria commonly associated with biologically contaminated water, using biofiltration. In this study, a laboratory-scale biofilter system was used to investigate the control of Escherichia coli, Enterococcus faecalis, and Pseudomonas aeruginosa in fresh water. Simulated fresh water was inoculated with the test pathogens at a starting inocula of ~1000 CFU 100 mL−1 to challenge the biofilters. Biofilter systems operating within a recirculation configuration demonstrated significant reduction of E. coli (99%), E. faecalis (99%), and P. aeruginosa (92%) after 24 h. Conversely, all sterile control systems did not show any significant reduction in pathogens. Subsequent analysis of the biofilter media after circulation showed that 0% of E. coli was recovered from the biofilter, whereas 0.06% and 1.26% of E. faecalis and P. aeruginosa were recovered respectively. Further investigation demonstrated the reduction of E. coli and enterococci from an environmentally-derived surface water of 99.8% and 99.4% respectively. In conclusion, this work demonstrates that biofilter systems can be used to significantly reduce waterborne pathogenic bacteria within fresh water. The potential application of low-cost, energy efficient biofilter systems for the management of waterborne bacterial pathogens in water supplies is discussed.

Intensified inactivation of model and environmental bacteria by an atmospheric-pressure air-liquid discharge plasma compared with chlorination

Water-borne pathogenic bacteria are always the top priority to be removed through disinfection process in water treatment due to their threat to human health. It was necessary to develop novel disinfection methods since the conventional chlorine disinfection was inefficient in inactivating chlorine-resistant bacteria, inducing the viable but non-culturable (VBNC) bacteria and forming disinfection by-products (DBPs). In this study, the inactivation of four model strains including Gram-negative (G−), Gram-positive (G+) and environmental samples by atmospheric-pressure air-liquid discharge plasma (ALDP) was assessed systematically. The results showed that ALDP was superior in inactivating all of the samples compared with chlorination. During 10 min ALDP treatment, the G− bacteria were completely inactivated, and the G+ one was inactivated by more than 4.61 logs. The inactivation of bacteria from a campus lake and a wastewater treatment plant effluent exceeded 99.82% and 97.78%, respectively. For G− bacteria, ALDP resulted in a much lower (102∼103 times) levels of VBNC cells than chlorination. ALDP could effectively remove the chlorine-resistant bacteria. More than 96.41% of the intracellular DNA and 99.99% of the extracellular DNA were removed, whereas it was only 56.35% and 12.82% for chlorination. ALDP had a stronger ability to destroy cell structure than chlorination, presumably due to the existence of ROS (·OH, 1O2 and O2−). GC-MS analysis showed that ALDP produced less DBPs than chlorination. These findings provided new insights for the application of discharge plasma in water disinfection, which could be complemental or alternative to the conventional disinfection methods.

Application of Hydrogen Peroxide to Improve the Microbiological Stability of Food Ice Produced in Industrial Facilities

This work was aimed to produce an “active” food ice to preserve its microbiological safety over time. With this in mind, ice cubes were processed with the addition of H2O2 to water before freezing. Four food ice productions were performed at the industrial level: one control trial without the addition of H2O2 (0OX) and three experimental trials obtained by adding 4, 8, and 12 mg/L of H2O2 (4OX, 8OX, and 12OX), respectively. After production, all food ice trials were artificially contaminated with 102 CFU/100 mL of water-borne pathogenic bacteria (Escherichia coli ATCC 25922, Enteroccus faecalis ATCC 29212, and Pseudomonas aeruginosa ATCC 27853) inoculated individually. Thawed ice samples were then subjected to microbiological analyses performed by the membrane filtration method and the results indicated that only trial 12OX was able to inactivate all bacteria strains. In conclusion, the addition of 12 mg/L H2O2 represents an optimal cost-effective strategy to preserve the microbiological stability of food ice even when it is improperly handled after production.

Electrochemical Bacteria Decontamination of Water Samples Using Fluid Permeable Electrochemical Cells

Waterborne pathogenic bacteria pose a health risk to human's health and is related to thousands of hospitalizations each year into the US. To decontaminate water from bacteria, chlorination, ozonation or UV treatment is typically performed. In this presentation we will describe a hand-held, inexpensive device that can inactivate high concentrations of bacteria in water (up to 104 CFU/mL), and biological broth (up to 108 CFU/mL) in seconds. This device consist of three flow-through electrochemical cells connected in series. A drop of hydrogen peroxide is added into the water volume to be decontaminated and then the aqueous volume is simply passed through the fluid permeable electrochemical cells and the bacteria are killed. This device can be used to decontaminate environmental waters to become safe to drink, or decontaminate biological wastes produced in research facilities.

Towards Clean and Safe Water: A Review on the Emerging Role of Imprinted Polymer-Based Electrochemical Sensors.

This review critically summarizes the knowledge of imprinted polymer-based electrochemical sensors for the detection of pesticides, metal ions and waterborne pathogenic bacteria, focusing on the last five years. MIP-based electrochemical sensors exhibit low limits of detection (LOD), high selectivity, high sensitivity and low cost. We put the emphasis on the design of imprinted polymers and their composites and coatings by radical polymerization, oxidative polymerization of conjugated monomers or sol-gel chemistry. Whilst most imprinted polymers are used in conjunction with differential pulse or square wave voltammetry for sensing organics and metal ions, electrochemical impedance spectroscopy (EIS) appears as the chief technique for detecting bacteria or their corresponding proteins. Interestingly, bacteria could also be probed via their quorum sensing signaling molecules or flagella proteins. If much has been developed in the past decade with glassy carbon or gold electrodes, it is clear that carbon paste electrodes of imprinted polymers are more and more investigated due to their versatility. Shortlisted case studies were critically reviewed and discussed; clearly, a plethora of tricky strategies of designing selective electrochemical sensors are offered to “Imprinters”. We anticipate that this review will be of interest to experts and newcomers in the field who are paying time and effort combining electrochemical sensors with MIP technology.

Antiviral Nanomaterials for Designing Mixed Matrix Membranes.

Membranes are helpful tools to prevent airborne and waterborne pathogenic microorganisms, including viruses and bacteria. A membrane filter can physically separate pathogens from air or water. Moreover, incorporating antiviral and antibacterial nanoparticles into the matrix of membrane filters can render composite structures capable of killing pathogenic viruses and bacteria. Such membranes incorporated with antiviral and antibacterial nanoparticles have a great potential for being applied in various application scenarios. Therefore, in this perspective article, we attempt to explore the fundamental mechanisms and recent progress of designing antiviral membrane filters, challenges to be addressed, and outlook.

The detection efficiency of digital PCR for the virulence genes of waterborne pathogenic bacteria

Abstract Waterborne pathogens are the primary concern for the safe reuse of wastewater. Although digital PCR (dPCR) is considered promising for absolutely quantitating genes, the detection efficiency of dPCR is affected by many factors. This study tested eight virulence genes of pathogenic bacteria on a control plasmid and reclaimed water samples with reported primer–probe sets and designed ones on quantitative PCR (qPCR) and dPCR. Probe efficiency, data analysis, and PCR inhibition were found to affect the detection efficiency of dPCR. Firstly, poor probe quality, which is determined by probe quenching and activation efficiencies, was the main cause of PCR failure. Secondly, even if the PCR was successful, the probe quality and signal intensity could still affect the quantitative process. Manual analysis of dPCR data on the weak signal intensity would significantly reduce errors. And lastly, the sensitivity of PCR inhibition was lower in dPCR than qPCR, but inhibition still existed. The dPCR produced various detection efficiencies for different targets in one sample indicating inconstant inhibitory effects. Dilution was still the proper approach to overcome inhibition, but decreased the detection limit. More studies are required to ensure accurate waterborne pathogen quantitation by dPCR.

A real-time LAMP-based dual-sample microfluidic chip for rapid and simultaneous detection of multiple waterborne pathogenic bacteria from coastal waters.

Waterborne pathogens are becoming a serious worldwide health hazard; thus, the regular monitoring of epidemic pathogens is urgently required for public safety. In the present study, we developed a microfluidic chip integrated loop-mediated isothermal amplification technique (on-chip LAMP) to simultaneously detect 10 waterborne pathogenic bacteria, Campylobacter jejuni, Listeria monocytogenes, Salmonella enterica, Shigella flexneri, Staphylococcus aureus, Vibrio alginolyticus, V. cholerae, V. parahemolyticus, V. vulnificus, and Yersinia enterocolitica. This method was capable of simultaneously completing 22 genetic analyses of two specimens and achieved limits of detection ranging from 7.92 × 10-3 to 9.54 × 10-1 pg of genomic DNA of pure bacteria per reaction. The processes from sample loading to microfluidic operation were in a highly automated format, and the LAMP reaction ran to completion within 35 minutes, with a minimal volume of 22 μl per each half of a single chip. The coefficient of variation for the time-to-positive value was less than 0.1, indicating an excellent reproducibility of the dual-sample on-chip LAMP assay. The clinical sensitivity and specificity in analyses of coastal water samples were 93.1% and 98.0%, respectively, in comparison with traditional microbiological methods. Our established dual-sample on-chip LAMP assay provides an effective multiple-pathogen analysis of waterborne bacterial pathogens. This indicates that the method is applicable for on-site detection and routine monitoring of waterborne bacteria in aquatic environments.

Quantitative microbial risk assessment for waterborne pathogens in a wastewater treatment plant and its receiving surface water body

BackgroundAccess to safe water for drinking and domestic activities remains a challenge in emerging economies like South Africa, forcing resource-limited communities to use microbiologically polluted river water for personal and household purposes, posing a public health risk. This study quantified bacterial contamination and the potential health hazards that wastewater treatment plant (WWTP) workers and communities may face after exposure to waterborne pathogenic bacteria in a WWTP and its associated surface water, respectively.ResultsEscherichia coli (Colilert®-18/ Quanti-Tray® 2000) and enterococci (Enterolert®/ Quanti-Tray® 2000) were quantified and definitively identified by real-time polymerase chain reaction targeting the uidA and tuf genes, respectively. An approximate beta-Poisson dose-response model was used to estimate the probability of infection (Pi) with pathogenic E. coli. Mean E. coli concentration ranged from 2.60E+ 02/100 mL to 4.84E+ 06/100 mL; enterococci ranged from 2.60E+ 02/100 mL to 3.19E+ 06/100 mL across all sampled sites. Of the 580 E. coli isolates obtained from this study, 89.1% were intestinal, and 7.6% were extraintestinal pathogenic E. coli. The 579 enterococci obtained were 50.4% E. faecalis (50.4%), 31.4% E. faecium, 3.5%, E. casseliflavus and 0.7% E. gallinarum. The community health risk stemming from the use of the water for recreational and domestic purposes revealed a greater health risk (Pi) from the ingestion of 1 mL of river water from upstream (range, 55.1–92.9%) than downstream (range, 26.8–65.3%) sites. The occupational risk of infection with pathogenic E. coli for workers resulting from a once-off unintentional consumption of 1 mL of water was 0% (effluent) and 23.8% (raw influent). Multiple weekly exposures of 1 mL over a year could result in a Pi of 1.2 and 100% for the effluent and influent, respectively.ConclusionOur findings reveal that there is a potentially high risk of infection for WWTP workers and communities that use river water upstream and downstream of the investigated WWTP.

SYNTHESIS AND ANTIBACTERIAL ACTIVITY OF COBALT-THIOUREA NANOPARTICLES ON SELECTED WATERBORNE BACTERIAL PATHOGENS

Traditional water treatment technologies have been used to treat wastewater to ensure continuous supply of pure drinking water. However, these have proved costly and ineffective. The use of nanoparticles, mainly to remove microbial contaminants is becoming a major area of research. The aim of this study was to synthesize, characterize and investigate antimicrobial activity of Cobalt-thiorea nanoparticles against selected waterborne pathogenic bacteria. Cobalt-thiourea nanoparticles with different ratios were synthesized via wet chemistry method and characterized through UV-Visible spectroscopy (UV-Vis), photoluminescence spectroscopy (PL), fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). FTIR spectral studies confirmed that the binding of thiourea with cobalt occurs through sulphur. The TGA curves indicated a two-step decomposition for Co-thiourea nanoparticles ratios. Morphology for ratios (1:1, 1:2, 1:3) were around 10-30 nanometers (nm) and dispersed. Ratio 2:1 particles were around 50 nm and agglomerated with irregular shapes. The X-Ray diffraction confirmed amorphous identity for metallic nanoparticles material. Co/thiourea nanoparticles showed strong antimicrobial activity by causing inhibition of growth for a wide range of Gram negative bacteria with low Minimum Inhibitory Concentration (MIC) values. Further research on metallic nanomaterials in water purification systems is needed to overcome the spread of waterborne bacterial infections and antimicrobial resistance.

Hydrobionts and Plants as Alternative Hosts for Sapronosis Pathogens

Relevance . Specific epidemiology of sapronotic (soilborne, waterborn) bacteria is characterized from the ecological point of view. The characteristic feature of soil-borne, water-born pathogens is an ability to exist autonomously in the environment. Aims . This analytical review is focused on hydrobionts and crops as alternative hosts for several soilborne and waterborne pathogenic bacteria (Vibrio, Legionella, Yersinia, Listeria monocytogenes). Conclusions . Published experimental results evidence capabilities of human and animal pathogens to colonize protozoan and plant tissues. Novel approaches are discussed to minimize risks of infection spreading.

Composition and Antibacterial Effects of Laurel (Laurus nobilis L.) Leaves Essential Oil

In the present study, the chemical composition of laurel (Laurus nobilis L.) leaves essential oil (EO) and its antibacterial effect on common food and water-borne pathogenic bacteria were investigated. The results showed that 1.8-cineol (41.1 %), sabinene (6.96 %), α-pinene (5.94 %), humulene epoxide II (5.73 %), and α-terpinenyl acetate (5.72 %) were the main compounds in the Laurus nobilis leaves EO. The EO showed the highest (P < 0.05) antibacterial effect on Enterococcus faecalis (28.0 mm, zone diameter), followed by Escherichia coli O:157 H:7 (27.1 mm) and Salmonella pullorum (25.2 mm). Regarding MIC/MBC ratios, Laurus nobilis EO had a bacteriocidal effect on all tested food and waterborne pathogens except of Listeria monocytogenes.

Computerized High-tech Detection Technology of Immunofluorescence Labelled Waterborne Pathogenic Bacteria

The waterborne pathogenic bacteria, especially the enteric bacteria of human fecal origin, have become currently a global public health issue. The detection and quantification of drinking water microorganisms have been an essential part of any quality control or water safety management plan interconnected to enteric bacterial pathogens such as Salmonella spp., Shigella spp., Vibrio cholerae or to non-faecal bacterial pathogens such as Pseudomonas aeruginosa. The standard methods of detecting waterborne pathogenic bacteria are time-consuming due to the bacterial growing step in a specific culture media, followed by isolation, microbiological and/or serological identi�cation and in some cases followed by subspeci�c characterization. This study aimed to develop a faster, powerful, more sensitive and reproducible diagnostic tool to monitor a specific pathogen contamination in drinking water (Pseudomonas aeruginosa) by specific antibody-antigen interactions followed by a computerized technology to identify bacteria as a digital image from water samples. Digital Image processing was carried out using National Instruments Vision Assistant Software. Pseudomonas aeruginosa was specifically detected by immunofluorescence technique with fluorophore tagged antibodies, and then the image formation in fluorescence microscopy was processed by computer vision software functions organized in pipeline-like data analysis processing. Overall, these techniques proved to be a reliable one, time-effective and sensitive for diagnosis and prevention of drinking water quality and waterborne bacterial disease.

Doped ZnO nanoparticles impregnated on Kaolinite (Clay): A reusable nanocomposite for photocatalytic disinfection of multidrug resistant Enterobacter sp. under visible light

Water contamination by multidrug resistant (MDR) enteric bacteria can be considered as the foremost cause of gastrointestinal infections and poses a threat to global public health. Therefore, there is an urgent need to pursue unorthodox techniques with potential of community scale applications for purging of water borne pathogenic bacteria. We communicate visible-light assisted photocatalytic disinfection (PCD) of an enteric MDR bacterium; Enterobacter sp. using Fe-doped ZnO nanoparticles impregnated on Kaolinite (Clay) (ZnO/K). ZnO/K was synthesized by co-precipitation technique and was found to be more effective than Fe-doped ZnO (ZnO) and Kaolinite for PCD process. Analysis from fluorescence microscopy and electron microscopy (FESEM) proposed complete bacterial cell death via PCD due to damage of bacterial cell membrane. Experimental evidences indicated that O2− could be acting as the most significant component in disinfection of MDR Enterobacter sp. in visible-light assisted PCD process in presence of ZnO/K. Considering the experimental data of Resazurin assay, it is proposed that reactive oxygen species (ROS) generated during PCD might have impeded the oxido-reductase enzyme system of the bacteria and hence trammeling its metabolic activity. Crystal structure and particle size of ZnO/K was found to be unaltered during the photocatalytic process indicating its potential for reusability. When ZnO/K was exposed to HCT-116 Human Colorectal Carcinoma cell lines, about 79% cell survivability was noticed. The synthesized material was successful in completely disinfecting the target microorganism in Zebra Fish model, without producing any adverse effects on the Fish itself, further reinforcing its biocompatibility factor. High effectiveness of PCD process using ZnO/K under visible light in disinfecting enteric MDR bacteria, might have promising outcome as an alternative water disinfection technology to prevent the spread of infectious and resistant bacteria without producing any adverse effect on non-specific flora and fauna.