Waterborne Pathogenic Bacteria Research Articles

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.

Decreased waterborne pathogenic bacteria in an urban aquifer related to intense shallow geothermal exploitation

The implications of intensive use of shallow geothermal energy resources in shallow urban aquifers are still not known for waterborne pathogens relevant to human health. Firstly, we hypothesized that waterborne enteric pathogens would be relatively increased in heated groundwater plumes. To prove this, microbiological sampling of 31 piezometers covering the domain of an urban groundwater body affected by microbiological contamination and energetically exploited by 70 groundwater heat pump systems was performed. Mean differences of pathogenic bacteria contents between impacted and non-impacted monitoring points were assessed with a two-tailed independent Student's t-test or Mann-Whitney U and correlation coefficients were also calculated. Surprisingly, the results obtained revealed a significant and generalized decrease in waterborne pathogen contents in thermally impacted piezometers compared to that of non-impacted piezometers. This decrease is hypothesized to be caused by a heat shock to bacteria within the heat exchangers. The statistically significant negative correlations obtained between waterborne pathogen counts and temperature could be explained by the spatial distribution of the bacteria, finding that bacteria start to recover with increasing distance from the injection point. Also, different behavior groups fitting exponential regression models were found for the bacteria species studied, justified by the different presence and influence of several aquifer parameters and major, minor and trace elements studied, as well as the coexistence with other bacteria species. The results obtained from this work reinforce the concept of shallow geothermal resources as a clean energy source, as they could also provide the basis to control the pathogenic bacteria contents in groundwater bodies.

Evaluation of Antibacterial Activity of Piper betel Leaves and Nigella sativa Seeds against Multidrug Resistant Food and Water Borne Pathogenic Bacteria: An in vitro Study Model

Evaluation of Antibacterial Activity of Piper betel Leaves and Nigella sativa Seeds against Multidrug Resistant Food and Water Borne Pathogenic Bacteria: An in vitro Study Model

Next-generation sequencing for investigating the diversity of microorganisms and pathogenic bacteria in a water source

Purpose: To employ next-generation sequencing (NGS) to investigate the diversity of microorganisms and pathogenic bacteria from a water source in Tai Lake, China, in winter. Methods: Water samples from the same source were collected over a period of 3 months (December 2013 to February 2014), and their physicochemical characteristics were determined. The DNA of the samples were extracted and amplified by polymerase chain reaction (PCR). The PCR products were sequenced by Miseq PE300 pyro sequencing platform. The results for 16S rDNA were analysed using visualization software Gephi, and the 16S rDNA gene pool of known pathogenic bacteria was established. Results: A total of 144,292 16S rDNA gene sequences were obtained and ranked by RDP classifier. The average length of the sequences was 395.66 bp. They revealed 580 operational taxonomic units (OTUs) classified into 16 phyla. A full length of 16S rDNA gene database of common pathogenic bacteria was established. After blasting, 17 species of pathogenic bacteria were found. The most abundant potential human pathogenic bacteria were affiliated to B. tribocorum . Most environmental factors had significant impact on pathogenic bacteria. Conclusion: These results indicate that NGS can be used for the simultaneous detection of most recognized water-borne pathogenic bacteria. Variations in microorganisms in water source at different periods in winter can provide insight into the diversity of microorganisms in the water. Keywords: Next-generation sequencing, Pathogenic bacteria, Diversity, 16S rDNA gene

Recent developments in detection and enumeration of waterborne bacteria: a retrospective minireview.

Waterborne diseases have emerged as global health problems and their rapid and sensitive detection in environmental water samples is of great importance. Bacterial identification and enumeration in water samples is significant as it helps to maintain safe drinking water for public consumption. Culture‐based methods are laborious, time‐consuming, and yield false‐positive results, whereas viable but nonculturable (VBNCs) microorganisms cannot be recovered. Hence, numerous methods have been developed for rapid detection and quantification of waterborne pathogenic bacteria in water. These rapid methods can be classified into nucleic acid‐based, immunology‐based, and biosensor‐based detection methods. This review summarizes the principle and current state of rapid methods for the monitoring and detection of waterborne bacterial pathogens. Rapid methods outlined are polymerase chain reaction (PCR), digital droplet PCR, real‐time PCR, multiplex PCR, DNA microarray, Next‐generation sequencing (pyrosequencing, Illumina technology and genomics), and fluorescence in situ hybridization that are categorized as nucleic acid‐based methods. Enzyme‐linked immunosorbent assay (ELISA) and immunofluorescence are classified into immunology‐based methods. Optical, electrochemical, and mass‐based biosensors are grouped into biosensor‐based methods. Overall, these methods are sensitive, specific, time‐effective, and important in prevention and diagnosis of waterborne bacterial diseases.

충남지역 지하수에서 분리한 총대장균군 양성시료 중 수인성 병원균의 분석

Chungcheongnam-do Institute of Health and Environment Research *Department of Environmental Engineering, Chungnam National University ABSTRACTObjectives: To ensure the microbiological safety of groundwater, it was confirmed whether waterbornepathogenic bacteria in groundwater samples tested positive for total coliforms in the Chungcheongnam-doProvince region. Methods: Total colony counts, total coliforms and fecal coliforms were tested according to the process mandatedby the drinking water quality testing standards of Korea. DNA was extracted from the samples, tested positivefor total coliforms, and then subjected to real-time PCR to detect waterborne pathogenic bacteria.Results: A total of 115 samples were inadequate for drinking water. Thirty-one cases (27%) showed positive forfecal coliforms and nine cases (7.8%) showed total colony counts exceeding drinking water standards. Twenty-seven cases (23.5%) showed three items (total colony counts, total coliforms and fecal coliforms). Using the real-time PCR method, waterborne pathogens were detected in 57 cases (49.6%) in 115 samples. Seventy-eight casesof waterborne pathogenic bacteria were detected (including duplications): 27 cases of pathogenic E. coli (EPEC(19), ETEC (5), EHEC (1), EAEC (1) and EIEC (1)); 45 of Bacillus cereus; two of Yersinia spp.; two ofSalmonella spp.; one of Staphylococcus aureus; one of Clostridium perfringens.Conclusion: The real-time PCR method can offer rapid and accurate detection of waterborne pathogenicbacteria. Therefore, this assay could be an alternative to conventional culture methods and can further ensure themicrobiological safety of groundwater.Keywords: Groundwater, real-time PCR, total coliforms, waterborne pathogenic bacteria

A comparative analysis of in vitro growth inhibition of waterborne bacteria with bioactive plant Lippia nodiflora L. and camphor

In the current scenario, due to global deterioration of the environment and climate change, among them water pollution possesses serious threat to most of the populace. Waterborne pathogenic bacteria like Escherichia coli, Vibrio cholerae, Salmonella typhimurium, Klebsiella pneumoniae, etc. are responsible for several diseases such as diarrhoea, cholera, salmonellosis, etc. In order to overcome these waterborne bacterial diseases and for purification of water, plants have been of great use for their potential role from very ancient times. The present study deals with the Clinical & Laboratory Standards Institute (CLSI)-recommended broth microdilution antibacterial susceptibility assay of waterborne bacterial pathogens against Lippia nodiflora L. petroleum ether (LNPE) and ethanolic extracts (LNEE) prepared from the leaves and flowers together of Lippia nodiflora (Verbenaceae), in comparison to camphor. Growth inhibition of tested bacterial pathogens was recorded in from of IC50 and MIC values were found to be 0.171, 0.327 (mg/ml) against E. coli and V. cholerae, respectively, for LNPE extract. Thus, LNPE justifies its potential in inhibiting the growth of tested waterborne bacterial pathogens and creates an interest in further testing its active fraction for in vivo trials and organoleptic analysis; making it a good herbal replacement for the conventional water treatment.

In-Silico Designing of Molecular Beacon Probes for Sensitive and Rapid Detection of Water Borne Pathogenic Bacteria

A handy and economic tool is needed for detection of water borne bacteria, the most prevalent pathogenic contaminant. For this purpose molecular beacon (MB) based biosensor, being highly specific, sensitive and functional without target labeling, can serve as an excellent detection tool for water quality analysis. A computational approach using MUMmer, Oligo, RNA structure as tools has been employed to identify suitable probes for designing MB for ten major water contaminating bacteria prevalent in Allahabad (Uttar Pradesh, India) region. In the present work conserved DNA regions and genes which are common in these bacterial species were taken as target regions for designing molecular beacons which were further screened on the basis of their folding stability and melting temperature range. Suggested probes can be synthesized and directly used as highly specific biological elements in biosensor designing. Such rationale designing of Biosensors can reduce detection cost and speed up more sensitive diagnostic strategies.

Foodborne and waterborne pathogenic bacteria in selected Organisation for Economic Cooperation and Development (OECD) countries.

The World Ranking Food Safety Performance reports by Charlebois in 2008 and 2010 importantly stimulated international discussion and encouraged efforts to establish realistic international benchmarks for food safety performance among Organisation for Economic Cooperation and Development (OECD) countries. This paper presents the international incidence of 5 common foodborne pathogens and describes the challenges of comparing international data. Data were compiled from surveillance authorities in the countries, such as the Natl. Notifiable Diseases Surveillance System of Australia; the Canadian Notifiable Diseases Surveillance System; the European Food Safety Authority, EFSA; the Ministry of Health, Labour and Welfare of Japan; New Zealand Food Safety Authority; and the U.S. Center for Disease Control and Prevention. The highest average rates in cases per 100000 people over the 12-y period from 2000 to 2011 for Campylobacter spp. (237.47), Salmonella spp. (67.08), Yersinia spp. (12.09), Verotoxigenic/Shiga toxin producing Escherichia coli (3.38), and Listeria monocytogenes (1.06) corresponded, in order, to New Zealand, Belgium, Finland, Canada, and Denmark. Comparatively, annual average rates for these 5 pathogens showed an increase over the 12-y period in 28%, 17%, 14%, 50%, and 6% of the countries for which data were available. Salmonella spp. showed a decrease in 56% of the countries, while incidence of L. monocytogenes was constant in most countries (94%). Variable protocols for monitoring incidence of pathogens among OECD countries remain. Nevertheless, there is evidence of sufficient standardization of monitoring protocols such as the European Surveillance System, which has contributed to reduce this gap.

Sea urchin Diadema africanum mass mortality in the subtropical eastern Atlantic: role of waterborne bacteria in a warming ocean

A widespread mass mortality event of the sea urchin Diadema africanum was detected in the subtropical eastern Atlantic, extending from Madeira to the Canary Islands, covering a straight- line distance of >400 km. This is the first disease- related die-off of a diadematid documented in the eastern Atlantic Ocean. Diseased individuals showed deterioration of the epidermis and water-vascular system, resulting in epidermal necrosis and release of spines. Despite some spatial heterogeneity in disease incidence at the study sites, there was a 65% overall reduction in urchin abundance after the mortality event compared to numbers pre-mortality. However, the reduction in urchin numbers did not compromise the species' reproductive success; the settlement peak following the mortality event was of a similar magnitude to that in prior years. Bacterial isolation and cul ture techniques, and subsequent laboratory in fection experiments, strongly suggested that Vibrio alginolyticus was involved in the disease. We hypo thesize that the mass mortality event devel- oped due to anomalously high seawater tempera- tures recorded in the 2 studied archipelagos and that warmer temperatures enabled infection of D. africa - num by waterborne pathogenic bacteria. Fluctua- tions in urchin populations are key in de termining the structure and functioning of benthic ecosystems: under the current seawater warming scenario, dis- ease may result in more frequent phase shifts, aiding the persistence of macroalgae.

Light-Activated Covalent Coating of Cotton with Bactericidal Hydrophobic Polycations

A methodology is developed and validated whereby a cotton fabric is impregnated with a photosensitive hydrophobic N-alkyl-polyethylenimine, followed by its covalent immobilization triggered by ultraviolet light. The resultant fabric efficiently kills on contact waterborne pathogenic bacteria E. coli and S. aureus.

Application of real-time polymerase chain reaction (PCR) coupled with ethidium monoazide treatment for selective quantification of viable bacteria in aquatic environment

Ethidium monoazide (EMA) was used to quantify DNA selectively from viable cells with healthy membrane/cell wall system, but not from dead cells, of a target bacterium in the aquatic environment using real-time PCR. Spiking experiments to determine the EMA treatment conditions showed that EMA treatment with EMA at 10-25 microg/ml and subsequent halogen light exposure for 2 min was suitable for selective quantification of DNA from viable cells in an aquatic sample using real-time PCR coupled with EMA treatment (real-time EMA-PCR). Optimized real-time EMA-PCR was applied in combination with culture-based method and conventional real-time PCR without EMA treatment to elucidate the behavior of an Escherichia coli strain inoculated into a pond water microcosm. Quantification results obtained using real-time EMA-PCR were lower than those by conventional real-time PCR without EMA treatment and higher than those by culture-based method. The results suggest that quantification by real-time EMA-PCR seemed to represent the viable population, which would partly include viable but non-culturable state bacteria. Real-time EMA-PCR optimized here can be a useful tool for selective monitoring of the viable population of a target bacterium in the aquatic environment, and thereby contribute to assessment of potential microbial risks generated from waterborne pathogenic bacteria.

Influence of adhesion to activated carbon particles on the viability of waterborne pathogenic bacteria under flow

In rural areas around the world, people often rely on water filtration plants using activated carbon particles for safe water supply. Depending on the carbon surface, adhering microorganisms die or grow to form a biofilm. Assays to assess the efficacy of activated carbons in bacterial removal do not allow direct observation of bacterial adhesion and the determination of viability. Here we propose to use a parallel plate flow chamber with carbon particles attached to the bottom plate to study bacterial adhesion to individual carbon particles and determine the viability of adhering bacteria. Observation and enumeration is done after live/dead staining in a confocal laser scanning microscope. Escherichiae coli adhered in higher numbers than Raoultella terrigena, except to a coconut-based carbon, which showed low bacterial adhesion compared to other wood-based carbon types. After adhesion, 83-96% of the bacteria adhering to an acidic carbon were dead, while on a basic carbon 54-56% were dead. A positively charged, basic carbon yielded 76-78% bacteria dead, while on a negatively charged coconut-based carbon only 32-37% were killed upon adhesion. The possibility to determine both adhesion as well as the viability of adhering bacteria upon adhesion to carbon particles is most relevant, because if bacteria adhere but remain viable, this still puts the water treatment system at risk, as live bacteria can grow and form a biofilm that can then be shedded to cause contamination.

Screening of Coliform group of bacteria and waterborne pathogenic bacteria from ground- water samples from Vasai, Thane district

The present study was carried out to study the microbiological characteristics of ground water samples collected from wells and bore wells near Mumbai. Samples were screened for coliform bacteria and waterborne pathogenic bacteria. The results indicated that all the water samples are highly polluted and not potable.

Isolation, purification, characterization, and physiological behavior of drinking water-borne pathogenic bacteria.

The present work was devoted for isolation, characterization, and studying physiological behavior of drinking water borne pathogenic bacteria isolated from tap and cooling water. Total of 171 bacterial isolates were isolated from twenty nine different localities on eight common and specific agar media (Nutrient, Salmonella & Shigella, Desoxycholate citrate, Eosin–methylene blue, Thioglycollate, Mannitol salt, MacConkey and Clostridium) agar media. All bacterial isolates were purified and characterized on the basis of morphological, physiological, and biochemical tests. These lead to the following suggested names: Bacillus cereus (8); B. badius (1); B. macerans (1); B. brevis (6); B. circulans (4); B. coagulans (3); B. firmus (4); B. globisporus (2); B. megaterium (10); B. mycoides (3); B. pantotheniticus (9); B .pasteurii (1); B. pumilus (1); Staphylococcus gallinarum (1); Staph. epidermidis (6); Staph. haemolyticus (1); Staph. sciuri (2); Enterobacter aerogenes (1); Micrococcus halobius (2); M. sedentarius (1); M. varians (1); Pseudomonas aeruginosa (6); Klebsiella oxytoca (2); K. pneumonia (3); Enterobacter agglomerans (3); Edwardsiella ictalluri (4); Citrobacter freundii (1); Salmonella typhi (3); S. pullorum (1); Shigella dysenteriae (2); Sh. flexneri (2); Proteus mirabilis (13); Providencia stuartii (1); Pro. Rettgeri (2); Proteus rettgeri (1) and Escherichia coli (2).Thirty six characterized bacterial strains were selected and studying some physiological characteristics and evaluating of their five extracellular enzymes potencies including α-amylase, cellulase, lipase, pectinase, and protease with percentage of 41.66, 41.66, 33.33, 11.11, & 94.44 % respectively among all selected bacterial strains. The selected water borne pathogenic bacterial strains were growing at different pH values covering a relatively wide range of pH (4-12). Minimum, maximum, and optimum pH values for their growth were determined as 4, 12, and 7 respectively. Selected isolates showed abundant growth within the temperature range of 10-55ºC. Bacterial strains succeeded to grow in sodium chloride free medium and also containing sodium chloride up to 12.5 % (w/v). Recorded data emphasized that tested drinking water samples were polluted with different waterborne pathogenic bacteria and by investigating its physiological behavior, the virulence of the 36 bacterial strains was controllable. New Egyptian Journal of Microbiology Vol. 17 (2) 2007: pp. 105-120

Thermal inactivation of water-borne pathogenic and indicator bacteria at sub-boiling temperatures

The use of harvested rainwater in domestic hot water systems can result in optimised environmental and economic benefits to urban water cycle management, however, the water quality and health risks of such a scenario have not been adequately investigated. Thermal inactivation analyses were carried out on eight species of non-spore-forming bacteria in a water medium at temperatures relevant to domestic hot water systems (55–65 °C), and susceptibilities to heat stress were compared using D-values. The D-value was defined as the time required to reduce a bacterial population by 90% or 1 log reduction. The results found that both tested strains of Enterococcus faecalis were the most heat resistant of the bacteria studied, followed by the pathogens Shigella sonnei biotype A and Escherichia coli O157:H7, and the non-pathogenic E. coli O3:H6. Pseudomonas aeruginosa was found to be less resistant to heat, while Salmonella typhimurium, Serratia marcescens, Klebsiella pneumoniae and Aeromonas hydrophila displayed minimal heat resistance capacities. At 65 °C, little thermal resistance was demonstrated by any species, with log reductions in concentration occurring within seconds. The results of this study suggested that the temperature range from 55 to 65 °C was critical for effective elimination of enteric/pathogenic bacterial components and supported the thesis that hot water systems should operate at a minimum of 60 °C.

リアルタイムPCR法による食中毒菌の迅速スクリーニングの検討

A duplex real-time SYBR Green LightCycler PCR (LC-PCR) assay with DNA extraction using QIAamp DNA Stool Minikit was evaluated for detection of 8 of 19 species of food-borne pathogens, including Plesiomonas shigelloides, Providencia alcalifaciens, in five stool specimens. The time frame was within 2h or less. The protocol used the same LC-PCR with 22 pairs of specific primers. The rapid amplification and reliable detection of specific genes were determined by this LC-PCR assay from 10 cases of food-borne outbreaks in Shimane Prefecture from 2002 to 2005. These cases included Campylobacter jejuni (4), Clostridium perfringens (2), enteropathogenic Escherichia coli and astA positive E. coli (1), and astA positive E. coli, enterohemorrhagic E. coli 026, and Bacillus cereus (1 each). Rapid amplification and reliable detection of specific genes of food-or water-borne pathogenic bacteria in fecal samples should facilitate the diagnosis and management of food-borne outbreaks.

The Inactivation of Microbes by Sunlight: Solar Disinfection as a Water Treatment Process

Publisher Summary This chapter reviews the solar water treatment. Sunlight is an important factor responsible for the inactivation of fecal bacteria in many natural environments, including fresh water and sea water, bathing waters, and waste waters. The chapter discusses the mechanisms of solar disinfection. This includes optical inactivation, thermal inactivation, and interaction between optical and thermal effects. At its simplest, batch-process solar disinfection, the method involves filling a transparent glass or plastic vessel with contaminated water and then keeping the vessel in full-strength sunlight for several hours to inactivate pathogenic microbes. Solar radiation can inactivate a wide range of micro-organisms—including fecal indicator bacteria such as Escherichia coli , water-borne pathogenic bacteria such as Salmonella typhi and Shigella flexneri , along with various yeasts and molds. Furthermore, solar disinfection is not universally applicable; it may be appropriate under circumstances in which there is no realistic alternative treatment process and where there is an unfulfilled need for safer water.

Duplex real-time SYBR green PCR assays for detection of 17 species of food- or waterborne pathogens in stools.

A duplex real-time SYBR Green LightCycler PCR (LC-PCR) assay with DNA extraction using the QIAamp DNA Stool Mini kit was evaluated with regard to detection of 8 of 17 species of food- or waterborne pathogens in five stool specimens in 2 h or less. The protocol used the same LC-PCR with 20 pairs of specific primers. The products formed were identified based on a melting point temperature (T(m)) curve analysis. The 17 species of food- or waterborne pathogens examined were enteroinvasive Escherichia coli, enteropathogenic E. coli, enterohemorrhagic E. coli, enterotoxigenic E. coli, enteroaggregative E. coli, Salmonella spp., Shigella spp., Yersinia enterocolitica, Yersinia pseudotuberculosis, Campylobacter jejuni, Vibrio cholerae, Vibrio parahaemolyticus, Vibrio vulnificus, Aeromonas spp., Staphylococcus aureus, Clostridium perfringens, and Bacillus cereus. No interference with the LC-PCR assay was observed when stool specimens were artificially inoculated with each bacterial species. The detection levels were approximately 10(5) food- or waterborne pathogenic bacteria per g of stool. The protocol for processing stool specimens for less than 10(4) food- or waterborne pathogenic bacteria per g of stool requires an overnight enrichment step to achieve adequate sensitivity. However, the rapid amplification and reliable detection of specific genes of greater than 10(5) food- or waterborne pathogenic bacteria per g in samples should facilitate the diagnosis and management of food- or waterborne outbreaks.