scholarly journals Assessing the Efciency of Detection of Vibrio cholerae Genetic Determinants Through Waterbody Vibrioflora Monitoring System

2021 ◽  
pp. 89-97
Author(s):  
L. V. Mironova ◽  
A. S. Ponomareva ◽  
E. A. Basov ◽  
I. S. Fedotova ◽  
Zh. Yu. Khunkheeva ◽  
...  
Keyword(s):  
Surface Water ◽  
Vibrio Cholerae ◽  
Monitoring System ◽  
Water Samples ◽  
Genetic Determinants ◽  
Water Reservoirs ◽  
Pcr Assay ◽  
Pcr Screening ◽  
Peptone Water ◽  
Integrated Study

Objective of the study was to assess the effectiveness of PCR screening of Vibrio cholerae genetic determinants in samples from surface water reservoirs for optimization of the cholera microbiological monitoring system.Materials and methods. The study was carried out as a part of the vibrioflora monitoring in surface water bodies in Irkutsk city. The study design included: 1) PCR screening of V. cholerae genetic determinants in nutrient-enriched (1 % peptone water) samples from surface water reservoirs during the monitoring period (824 samples); 2) studying of the V. cholerae DNA accumulation dynamics applying PCR assay of the samples from surface water reservoirs during cultivation on the enriched media (16 samples in dynamics); 3) experimental study of the detected V. cholerae concentrations in samples from surface water reservoirs. Species-specifc (hlyA, toxR) and serogroup-specifc (wbeT, wbfR) V. cholerae determinants were indicated in PCR with hybridization-fluorescent and electrophoretic detection.Results and discussion. At the frst stage it was found that the proportion of the positive samples through PCR screening (33.9 %) exceeded the percentage of the positive samples in bacteriological examination (19.3 %) (t=6.6; p<0,01). In the assessment of DNA accumulation dynamics, a decrease in the threshold cycle (Ct) by 1.2–5.2 times was recorded, indicating an increase in the V. cholerae concentration and proving the detection of genetic determinants of viable forms during PCR screening. An extended study of PCR-positive but bacteriologically negative samples made it possible to additionally isolate 4 V. cholerae cultures. However, there were no differences in the sensitivity of PCR screening and bacteriological analysis in the experiment with water samples artifcially contaminated with V. cholerae unlike the analysis of the enriched native samples. It can be determined by the metabolism and adaptation peculiarities of the microorganism in different environmental conditions. The results of the integrated study indicate the epidemiological effectiveness of PCR screening which gives grounds to recommend its application in monitoring studies of vibrioflora from environment after preliminary enrichment on liquid nutrient media in the work of federal, territorial, and regional laboratories.

Rapid and specific detection of Salmonella in water samples using real-time PCR and High Resolution Melt (HRM) curve analysis

2011 ◽  
Vol 64 (12) ◽  
pp. 2453-2459 ◽  
Author(s):  
G. N. van Blerk ◽  
L. Leibach ◽  
A. Mabunda ◽  
A. Chapman ◽  
D. Louw
Keyword(s):  
Surface Water ◽  
High Resolution ◽  
Real Time ◽  
Water Samples ◽  
Real Time Pcr ◽  
Curve Analysis ◽  
Pcr Assay ◽  
High Resolution Melt ◽  
Gene Target ◽  
Enrichment Step

A real-time PCR assay combined with a pre-enrichment step for the specific and rapid detection of Salmonella in water samples is described. Following amplification of the invA gene target, High Resolution Melt (HRM) curve analysis was used to discriminate between products formed and to positively identify invA amplification. The real-time PCR assay was evaluated for specificity and sensitivity. The assay displayed 100% specificity for Salmonella and combined with a 16–18 h non-selective pre-enrichment step, the assay proved to be highly sensitive with a detection limit of 1.0 CFU/ml for surface water samples. The detection assay also demonstrated a high intra-run and inter-run repeatability with very little variation in invA amplicon melting temperature. When applied to water samples received routinely by the laboratory, the assay showed the presence of Salmonella in particularly surface water and treated effluent samples. Using the HRM based assay, the time required for Salmonella detection was drastically shortened to less than 24 h compared to several days when using standard culturing methods. This assay provides a useful tool for routine water quality monitoring as well as for quick screening during disease outbreaks.

scholarly journals Detection of Giardia intestinalis in water samples collected from natural water reservoirs and wells in northern and north-eastern Poland using LAMP, real-time PCR and nested PCR

2017 ◽  
Vol 15 (5) ◽  
pp. 775-787 ◽  
Author(s):  
Anna Lass ◽  
Beata Szostakowska ◽  
Krzysztof Korzeniewski ◽  
Panagiotis Karanis
Keyword(s):  
Surface Water ◽  
Real Time ◽  
Water Samples ◽  
Real Time Pcr ◽  
Nested Pcr ◽  
Lamp Assay ◽  
Giardia Intestinalis ◽  
Detection Methods ◽  
Rrna Gene ◽  
Water Reservoirs

Giardia intestinalis is a protozoan parasite, transmitted to humans and animals by the faecal–oral route, mainly through contaminated water and food. Knowledge about the distribution of this parasite in surface water in Poland is fragmentary and incomplete. Accordingly, 36 environmental water samples taken from surface water reservoirs and wells were collected in Pomerania and Warmia-Masuria provinces, Poland. The 50 L samples were filtered and subsequently analysed with three molecular detection methods: loop-mediated isothermal amplification (LAMP), real-time polymerase chain reaction (real-time PCR) and nested PCR. Of the samples examined, Giardia DNA was found in 15 (42%) samples with the use of LAMP; in 12 (33%) of these samples, Giardia DNA from this parasite was also detected using real-time PCR; and in 9 (25%) using nested PCR. Sequencing of selected positive samples confirmed that the PCR products were fragments of the Giardia intestinalis small subunit rRNA gene. Genotyping using multiplex real-time PCR indicated the presence of assemblages A and B, with the latter predominating. The results indicate that surface water in Poland, as well as water taken from surface wells, may be a source of Giardia strains which are potentially pathogenic for humans. It was also demonstrated that LAMP assay is more sensitive than the other two molecular assays.

scholarly journals Molecular-Beacon Multiplex Real-Time PCR Assay for Detection of Vibrio cholerae

2006 ◽  
Vol 72 (9) ◽  
pp. 6424-6428 ◽  
Author(s):  
Aneta J. Gubala ◽  
David F. Proll
Keyword(s):  
Vibrio Cholerae ◽  
Real Time ◽  
Water Samples ◽  
Real Time Pcr ◽  
Molecular Beacon ◽  
Environmental Water ◽  
Molecular Beacons ◽  
Pcr Assay ◽  
Specificity And Sensitivity ◽  
Pcr Assays

ABSTRACT A multiplex real-time PCR assay was developed using molecular beacons for the detection of Vibrio cholerae by targeting four important virulence and regulatory genes. The specificity and sensitivity of this assay, when tested with pure culture and spiked environmental water samples, were high, surpassing those of currently published PCR assays for the detection of this organism.

scholarly journals Molecular genetic basis of biofilm formation as a component of Vibrio Cholerae persistence in water reservoirs of Russian Federation

2018 ◽  
Vol 16 (4) ◽  
pp. 23-32 ◽  
Author(s):  
Svetlana V. Titova ◽  
Elena V. Monakhova ◽  
Ludmila P. Alekseeva ◽  
Ruslan V. Pisanov
Keyword(s):  
Vibrio Cholerae ◽  
Biofilm Formation ◽  
Tap Water ◽  
Gene Clusters ◽  
Structural Features ◽  
Negative Regulator ◽  
World Health ◽  
Genetic Determinants ◽  
Water Reservoirs ◽  
Potential Threat

Background. The problem of cholera remains acute for world health service and risks of importation of Vibrio cholerae strains from endemic countries to Russia do exist. Toxigenic strains (carrying cholera toxin genes ctxAB) can cause epidemic outbreaks of cholera and non-toxigenic (ctxAB-) – single or multiple cases of cholera-like diarrhea. Investigation of their ability to survive in water reservoirs in climatic conditions of middle latitudes by means of forming biofilms is essential for potential threat evaluation. Materials and methods. Biofilm formation by 15 V. cholerae strains on abiotic surfaces was studied in microcosms with tap water and cover glasses. Identification of responsible genetic determinants in whole genome sequences and bioinformatics analysis were performed using BioEdit 7.2.5, BLASTN 2.2.29, Blastp and Vector NTI Advance 11 software. Results. The strains investigated differed in terms of biofilm formation which correlated with structural features of genes for MSHA pili (msh), matrix polysaccharides (vps) and proteins (rbm) as well as for certain regulatory factors. Strains with none or few genetic deviations from prototypes formed mature biofilms in 5-7 days while those containing truncated genes mshL, mshN, rbmC – only in 13 days. One strain with truncated gene for positive regulator vpsR formed an immature biofilm. Acceleration of the process in some strains up to 2-3 days correlated with either truncated gene hapR (negative regulator) or altered structure of both msh and vps-rbm gene clusters. Conclusion. Analysis of genetic determinants responsible for biofilm formation may be used for prediction of V. cholerae ability to survive in environmental objects of Russia and thus the potential danger of the latters as sources of infection.

Model of Vibrio cholerae biofilm as a mechanism of its survival in surface water reservoirs

2014 ◽  
Vol 7 (1) ◽  
pp. 12-18
Author(s):  
E. S. Kulikalova ◽  
S. G. Sappo ◽  
L. Ya. Urbanovich ◽  
E. Yu. Markov ◽  
L. V. Mironova ◽  
...  
Keyword(s):  
Surface Water ◽  
Vibrio Cholerae ◽  
Water Reservoirs

Occurrence of 1,4-dioxane and MTBE in drinking water sources in Japan

2006 ◽  
Vol 6 (2) ◽  
pp. 47-53 ◽  
Author(s):  
D. Simazaki ◽  
M. Asami ◽  
T. Nishimura ◽  
S. Kunikane ◽  
T. Aizawa ◽  
...  
Keyword(s):  
Drinking Water ◽  
Surface Water ◽  
Water Samples ◽  
Quality Standards ◽  
Raw Water ◽  
Water Quality Standards ◽  
Butyl Ether ◽  
Water Treatment Plants ◽  
Standard Value ◽  
Surface Water Samples

Nationwide surveys of 1,4-dioxane and methyl-t-butyl ether (MTBE) levels in raw water used for the drinking water supply were conducted at 91 water treatment plants in Japan in 2001 and 2002, prior to the revision of the drinking water quality standards. 1,4-dioxane was widely and continuously detected in raw water samples and its occurrence was more frequent and its concentrations higher in groundwater than in surface water. However, its maximum concentration in raw water was much lower than its new standard value (50 μg/L), which was determined as a level of 10−5 excessive cancer risk to humans. Trace levels of MTBE were also detected in several surface water samples.

Enumeration of Cryptosporidium oocysts from surface water concentrates by laser-scanning cytometry

2000 ◽  
Vol 41 (7) ◽  
pp. 197-202 ◽  
Author(s):  
F. Zanelli ◽  
B. Compagnon ◽  
J. C. Joret ◽  
M. R. de Roubin
Keyword(s):  
Surface Water ◽  
Water Samples ◽  
Laser Scanning ◽  
Immunomagnetic Separation ◽  
Entire Surface ◽  
Cryptosporidium Oocysts ◽  
Different Types ◽  
Laser Scanning Cytometry ◽  
Direct Microscopic Observation

The utilization of the ChemScan® RDI was tested for different types of water concentrates. Concentrates were prepared by cartridge filtration or flocculation, and analysed either without purification, or after Immunomagnetic separation (IMS) or flotation on percoll-sucrose gradients. Theenumeration of the oocysts was subsequently performed using the ChemScan® RDI Cryptosporidium application. Enumeration by direct microscopic observation of the entire surface of the membrane was carried out as a control, and recoveries were calculated as a ratio between the ChemScan® RDI result and the result obtained with direct microscopic enumeration. The Chemscan enumeration technique proved reliable, with recoveries yielding close to 100% in most cases (average 125%, range from 86 to 467%) for all the concentration/purification techniques tested. The quality of the antibodies was shown to be critical, with antibodies from some suppliers yielding recoveries a low as 10% in some cases. This difficulty could, however, be overcome by the utilization of the antibody provided by Chemunex. These data conclusively prove that laser scanning cytometry, which greatly facilitates the microscopic enumeration of Cryptosporidium oocysts from water samples and decreases the time of observation by four to six times, can be successfully applied to water concentrates prepared from a variety of concentration/purification techniques.

scholarly journals Bacterial diversity and predicted enzymatic function in a multipurpose surface water system – from wastewater effluent discharges to drinking water production

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Ananda Tiwari ◽  
Anna-Maria Hokajärvi ◽  
Jorge Santo Domingo ◽  
Michael Elk ◽  
Balamuralikrishna Jayaprakash ◽  
...  
Keyword(s):  
Drinking Water ◽  
Surface Water ◽  
Bacterial Community ◽  
Human Health ◽  
Bacterial Diversity ◽  
Water Samples ◽  
Bacterial Communities ◽  
Treatment Process ◽  
Pollution Sources ◽  
Production Well

Abstract Background Rivers and lakes are used for multiple purposes such as for drinking water (DW) production, recreation, and as recipients of wastewater from various sources. The deterioration of surface water quality with wastewater is well-known, but less is known about the bacterial community dynamics in the affected surface waters. Understanding the bacterial community characteristics —from the source of contamination, through the watershed to the DW production process—may help safeguard human health and the environment. Results The spatial and seasonal dynamics of bacterial communities, their predicted functions, and potential health-related bacterial (PHRB) reads within the Kokemäenjoki River watershed in southwest Finland were analyzed with the 16S rRNA-gene amplicon sequencing method. Water samples were collected from various sampling points of the watershed, from its major pollution sources (sewage influent and effluent, industrial effluent, mine runoff) and different stages of the DW treatment process (pre-treatment, groundwater observation well, DW production well) by using the river water as raw water with an artificial groundwater recharge (AGR). The beta-diversity analysis revealed that bacterial communities were highly varied among sample groups (R = 0.92, p <  0.001, ANOSIM). The species richness and evenness indices were highest in surface water (Chao1; 920 ± 10) among sample groups and gradually decreased during the DW treatment process (DW production well; Chao1: 320 ± 20). Although the phylum Proteobacteria was omnipresent, its relative abundance was higher in sewage and industrial effluents (66–80%) than in surface water (55%). Phyla Firmicutes and Fusobacteria were only detected in sewage samples. Actinobacteria was more abundant in the surface water (≥13%) than in other groups (≤3%). Acidobacteria was more abundant in the DW treatment process (≥13%) than in others (≤2%). In total, the share of PHRB reads was higher in sewage and surface water than in the DW treatment samples. The seasonal effect in bacterial communities was observed only on surface water samples, with the lowest diversity during summer. Conclusions The low bacterial diversity and absence of PHRB read in the DW samples indicate AGR can produce biologically stable and microbiologically safe drinking water. Furthermore, the significantly different bacterial communities at the pollution sources compared to surface water and DW samples highlight the importance of effective wastewater treatment for protecting the environment and human health.

scholarly journals Hydrogeochemistry and surface water quality assessment of IB valley coalfield area, India

2021 ◽  
Vol 11 (9) ◽  
Author(s):  
Bishnu Prasad Sahoo ◽  
Himanshu Bhushan Sahu ◽  
Dhruti Sundar Pradhan
Keyword(s):  
Water Quality ◽  
Heavy Metal ◽  
Seasonal Variation ◽  
Surface Water ◽  
Water Samples ◽  
Nickel Aluminum ◽  
Acid Mine ◽  
Significant Seasonal Variation ◽  
Cadmium Selenium ◽  
High Degree

AbstractCoal mining and ancillary activities have the potential to cause water pollution characterized by acid mine drainage, acid mine leachates, extreme pH conditions and heavy metal contaminations. In the present work, 33 water samples in premonsoon and 34 water samples in monsoon were collected from the surface water bodies of Ib Valley coalfield, India for hydrogeochemical analysis. In premonsoon, pH, TSS, Turbidity, DO, BOD, COD, Magnesium, Cadmium, Selenium, Nickel, Aluminum and in monsoon, pH, TSS, Turbidity, DO, BOD, COD, Iron, Cadmium, Selenium, Nickel and Aluminum were nonconforming to the permissible limit set by the Bureau of Indian Standards, World Health Organisation and Ministry of Environment, Forest and Climate Change, Government of India. The average BOD/COD ratio of less than 0.6 in both seasons indicated Ib valley coalfield water was not fairly biodegradable. The analysis of variance (ANOVA) revealed that significant seasonal variation (p < 0.05) was observed in the hydro-chemical parameters viz. TSS, turbidity, redox potential, acidity, total hardness, bicarbonate alkalinity, chloride, sulfate, nitrate, sodium, calcium, magnesium, iron, cadmium, chromium and magnesium during the entire sampling period. Whereas, no significant seasonal variation (p > 0.05) was observed in pH, EC, TDS, DO, BOD, residual chlorine, COD, oil and grease, fluoride, potassium, zinc, copper, selenium, nickel, aluminum, boron, silica, temperature, salinity, cyanide and phenol. Water Quality Index revealed that 39.39% and 35.29% samples belong to poor water quality category in premonsoon and monsoon, respectively. As per Heavy Metal Pollution Index, Degree of Contamination (Cd) and Heavy metal evaluation index, medium degree of pollution were exhibited by 51.52%, 30.30% and 45.45% samples in premonsoon and 20.59%, 35.29% and 26.47% samples in monsoon. Whereas, 5.88%, 2.94% and 5.88% samples were having high degree of pollution in monsoon and 15.15% samples caused high degree of pollution with respect to Cd in premonsoon. However, EC, Na%, PI, SAR and RSC values suggested that the water can be used for irrigation. Water type of the region had been found to be Ca–Mg–Cl–SO4 by Piper diagram.

scholarly journals Development of Surface Molecularly Imprinted Polymers as Dispersive Solid Phase Extraction Coupled with HPLC Method for the Removal and Detection of Griseofulvin in Surface Water

2019 ◽  
Vol 17 (1) ◽  
pp. 134 ◽  
Author(s):  
Kamran Bashir ◽  
Zhimin Luo ◽  
Guoning Chen ◽  
Hua Shu ◽  
Xia Cui ◽  
...  
Keyword(s):  
Surface Water ◽  
Solid Phase Extraction ◽  
Molecularly Imprinted Polymers ◽  
Water Samples ◽  
Solid Phase ◽  
Phase Extraction ◽  
Dispersive Solid Phase Extraction ◽  
Molecularly Imprinted ◽  
Imprinted Polymers ◽  
Surface Water Samples

Griseofulvin (GSF) is clinically employed to treat fungal infections in humans and animals. GSF was detected in surface waters as a pharmaceutical pollutant. GSF detection as an anthropogenic pollutant is considered as a possible source of drug resistance and risk factor in ecosystem. To address this concern, a new extraction and enrichment method was developed. GSF-surface molecularly imprinted polymers (GSF-SMIPs) were prepared and applied as solid phase extraction (SPE) sorbent. A dispersive solid phase extraction (DSPE) method was designed and combined with HPLC for the analysis of GSF in surface water samples. The performance of GSF-SMIPs was assessed for its potential to remove GSF from water samples. The factors affecting the removal efficiency such as sample pH and ionic strength were investigated and optimized. The DSPE conditions such as the amount of GSF-SMIPs, the extraction time, the type and volume of desorption solvents were also optimized. The established method is linear over the range of 0.1–100 µg/mL. The limits of detection and quantification were 0.01 and 0.03 µg/mL respectively. Good recoveries (91.6–98.8%) were achieved after DSPE. The intra-day and inter-day relative standard deviations were 0.8 and 4.3% respectively. The SMIPs demonstrated good removal efficiency (91.6%) as compared to powder activated carbon (67.7%). Moreover, the SMIPs can be reused 10 times for water samples. This is an additional advantage over single-use activated carbon and other commercial sorbents. This study provides a specific and sensitive method for the selective extraction and detection of GSF in surface water samples.

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