Comparison of three different media for the detection of E. coli and coliforms in water

2006 ◽  
Vol 54 (3) ◽  
pp. 141-145 ◽  
Author(s):  
C. Bernasconi ◽  
G. Volponi ◽  
L. Bonadonna
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Membrane Filtration ◽  
Simultaneous Detection ◽  
Alternative Methods ◽  
Phenotypic Characteristic ◽  
Iso Standard ◽  
E Coli ◽  
Microbiological Parameters ◽  
Filtration Technique

The European Drinking Water Directive defines reference methods for the enumeration of microbiological parameters in drinking water. The method to be used for Escherichia coli and coliforms is the membrane filtration technique on Lactose TTC agar with Tergitol 7. Many technical drawbacks of the procedure, as well as its limitations regarding the recent taxonomy of coliforms, make it necessary to evaluate alternative methods. Two alternative assays, a chromogenic media (m-ColiBlu24®) and a defined substrate technology-DST test (Colilert 18/Quanty Tray™) were compared with the ISO standard with attention to the phenotypic characteristic of the isolates. Results showed that the ISO method failed to detect an important percentage of coliforms and E. coli while m-ColiBlu24® and Colilert 18 provided results in a shorter time allowing the simultaneous detection of E. coli and coliforms with no further confirmation steps.

scholarly journals Membrane filtration media for the enumeration of coliform organisms and Escherichia coli in water: comparison of Tergitol 7 and lauryl sulphate with Teepol 610

1980 ◽  
Vol 85 (2) ◽  
pp. 181-191 ◽  
Author(s):  
Keyword(s):  
Escherichia Coli ◽  
Water Samples ◽  
False Positive ◽  
Membrane Filtration ◽  
Sodium Lauryl Sulphate ◽  
Standard Medium ◽  
E Coli ◽  
Laboratory Trial ◽  
Positive Results ◽  
Filtration Technique

SUMMARYIn a multi-laboratory trial with the mombrane filtration technique, three surfactants – Teepol 610 (T610), Tergitol 7 (T7) and sodium lauryl sulphate (LS) – were compared in media for the enumeration of coliform organisms and Escherichia coli in water. A total of 170 samples of water (87 raw and 92 marginally chlorinated) were examined for colony counts of coliform organisms, and 185 water samples (94 raw and 91 marginally chlorinated) for E. coli. Slight differences in the confirmed colony counts between the three media were noted, but few of these were observed consistently in every laboratory. In most laboratories, T7 gave slightly higher counts of E. coli than LS with chlorinated waters; a higher incidence of false-positive results for E. coli at 44 °C was also noted with T7. As there were no outstanding differences in the trial, sodium lauryl sulphate, which is chemically defined, cheap and readily available, is therefore recommended for use at a concentration of 0·1% instead of Teepol 610 in the standard medium for the enumeration of coliform organisms and E. coli in water by the membrane filtration technique.

scholarly journals Assessment of microbial contamination of drinking water with total coliform bacteria and Escherichia coli in the Bitola region

2019 ◽  
Vol 65 (2) ◽  
pp. 23-32
Author(s):  
Marta Nedelkova ◽  
Angela Delova ◽  
Tanja Petreska Ivanovska ◽  
Zoran Zhivikj ◽  
Lidija Petrushevska-Tozi
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Water Supply ◽  
Rural Areas ◽  
Membrane Filtration ◽  
Total Coliform ◽  
Coliform Bacteria ◽  
Quality And Safety ◽  
E Coli ◽  
Total Coliform Bacteria

The aim of this paper is to analyze the presence of Escherichia coli (E. coli) and total coliform bacteria (CB) in the drinking water of urban and rural areas of the Bitola region, as indicators for water quality and safety. All water in urban area is chlorinated, while at the same time the water in rural areas is non-chlorinated. The samples were analyzed according to the international standard method of membrane filtration MKC EN ISO 9308-1:2015. In all examined samples of drinking water in urban area, presence of E. coli and CB was not detected as a result of the disinfection of the water. On contrary, in all tested samples of the water from the rural water supply, presence of E. coli and CB was confirmed. Significant increase in coliform bacterial counts probably weather-related was found in the period from April to September. In addition, in the third quarter including July, August, and September, in many measurements, E. coli as an indicator of faecal contamination was identified in drinking water. In accordance with these findings and in order to provide safe drinking water, it is necessary to modernize the water supply for the population in rural areas, to disinfect permanently the drinking water and to apply regular laboratory controls which are a basic pre-condition. Otherwise, inappropriate management of the water systems can cause serious decrease in the quality and safety of the drinking water associated with an increased risk of appearance of the infectious diseases in people and hydric epidemic. Key words: drinking water, Escherichia coli, coliform bacteria, membrane filtration

scholarly journals Taqman hydrolysis probe application for Escherichia coli, Salmonella enterica, and Vibrio cholerae detection in surface and drinking water

2019 ◽  
Vol 9 (3) ◽  
pp. 492-499
Author(s):  
Ahmed K. A. El-Sayed ◽  
Mohamed I. Abou-Dobara ◽  
Camelia A. Abdel-Malak ◽  
Amira A. E. El-Badaly
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Vibrio Cholerae ◽  
Salmonella Enterica ◽  
Membrane Filtration ◽  
Quantitative Polymerase Chain Reaction ◽  
Bacterial Count ◽  
Distribution Networks ◽  
E Coli ◽  
Taqman Qpcr

Abstract This study explored the applicability of using TaqMan qPCR (quantitative polymerase chain reaction) for Escherichia coli, Salmonella enterica and non-virulent Vibrio cholerae detection in surface and drinking water. One hundred and twenty water samples were collected monthly (January 2017–December 2017) from the surface water (input) and drinking water (output and distribution networks) of two drinking water treatment plants (DWTPs) in Damietta County, Egypt. The distribution of the studied bacteria based on their detection by TaqMan qPCR compared with membrane filtration (MF) technique showed that the higher positive samples were detected by TaqMan qPCR. The bacterial count was totally absent in all output samples. TaqMan qPCR assay (based on sequence detection of uidA, invA, and ompW) revealed 97.96%, 99.14%, and 98.3% specificity for E. coli, S. enterica, and non-virulent V. cholerae, respectively, compared with 100% specificity for all strains when MF cultures were applied. TaqMan qPCR exhibited 100% sensitivity for all strains, while it was 91.67%, 80%, and 50% using MF cultures for E. coli, S. enterica, and non-virulent V. cholerae, respectively. In conclusion, TaqMan qPCR sensitivity makes it a useful tool for urgent fast monitoring of water contamination, especially in network samples that contain low bacterial count.

scholarly journals A Syringe-Based Biosensor to Rapidly Detect Low Levels of Escherichia Coli (ECOR13) in Drinking Water Using Engineered Bacteriophages

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1953 ◽  
Author(s):  
Troy C. Hinkley ◽  
Spencer Garing ◽  
Paras Jain ◽  
John Williford ◽  
Anne-Laure M. Le Ny ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Membrane Filtration ◽  
Genetically Engineered ◽  
World Health ◽  
Selective Enrichment ◽  
E Coli ◽  
Detection Assay ◽  
Colony Forming Units ◽  
Health Organization

A sanitized drinking water supply is an unconditional requirement for public health and the overall prosperity of humanity. Potential microbial and chemical contaminants of drinking water have been identified by a joint effort between the World Health Organization (WHO) and the United Nations Children’s Fund (UNICEF), who together establish guidelines that define, in part, that the presence of Escherichia coli (E. coli) in drinking water is an indication of inadequate sanitation and a significant health risk. As E. coli is a nearly ubiquitous resident of mammalian gastrointestinal tracts, no detectable counts in 100 mL of drinking water is the standard used worldwide as an indicator of sanitation. The currently accepted EPA method relies on filtration, followed by growth on selective media, and requires 24–48 h from sample to results. In response, we developed a rapid bacteriophage-based detection assay with detection limit capabilities comparable to traditional methods in less than a quarter of the time. We coupled membrane filtration with selective enrichment using genetically engineered bacteriophages to identify less than 20 colony forming units (CFU) E. coli in 100 mL drinking water within 5 h. The combination of membrane filtration with phage infection produced a novel assay that demonstrated a rapid, selective, and sensitive detection of an indicator organism in large volumes of drinking water as recommended by the leading world regulatory authorities.

scholarly journals Isolation of Multi Drug Resistant Escherichia coli from drinking water of Lahore City, Pakistan

2021 ◽  
Vol 15 (5) ◽  
pp. 1080-1083
Author(s):  
Nazia Mir ◽  
Sidrah Saleem ◽  
Muhammad Imran ◽  
Ayesha Ghazal ◽  
Muhammad Usman
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Membrane Filtration ◽  
Diffusion Method ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Antibiotic Resistant ◽  
Acinetobacter Species ◽  
E Coli ◽  
Lahore City

Background: The major faecal coliform is Escherichia coli which contaminates the drinking water from human and animal faecal waste. In developing regions drinking water is a vital source of microbiological pathogens. Multi-drug resistant (MDR) is defined as resistance to one or more antibiotic groups. An E. coli count greater than 4/dl in municipal drinking water is indicative of unacceptable fecal contamination. Aim: To find out the frequency of MDR E. coli in water system of Lahore, Pakistan. Methodology: Drinking water was collected from different towns of Lahore. The samples were processed using Membrane Filtration Technique. In the present study, Multidrug Resistant E.coli was isolated and antibiotic resistant pattern was seen against 16 most commonly antimicrobials, using Kirby Bauer disc diffusion method. Results: Total 100 water samples were collected, frequency of Escherichia coliisolated was 27% and frequency of MDR E.coli was 19%. The highest resistance showed by the organism towards Ampicillin (AMP) 21(81.48%), Augmentin (AMC), and Ceftazidime (CAZ) 14(51.85%) respectively. In this study also frequency of Extended Spectrum β-Lactamases were seen. Most common organisms isolated were E. coli 7% and Klebsiella 5%. Frequency of other coliforms isolated from drinking water other than E. coli was Klebsiella species 26%, Pseudomonas species 27%, Enterobacter 7%, Citrobacter species 8% and Acinetobacter species 5%. Conclusion: This study revealed that drinking water of Lahore city is heavilycontaminated with pathogenic microorganisms. A high proportion of antibiotic resistant is due to overuse of antibiotics, in patients with mild infections and secretion of these resistant bacteria from patients to environment. One of the reasons could be the mixing of sewage lines with drinking water supply. So, there is solely requirement for further studies for the identification of the sources for these contaminants. Keywords: Isolates, E. coli, Klebsiella, Multi-drug resistant (MDR)

Isolation of Multi Drug Resistant Escherichia coli from drinking water of Lahore City, Pakistan

2021 ◽  
Vol 15 (6) ◽  
pp. 1188-1191
Author(s):  
N. Mir ◽  
S. Saleem ◽  
M. Imran ◽  
A. Ghazal ◽  
M. Usman
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Membrane Filtration ◽  
Diffusion Method ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Antibiotic Resistant ◽  
Acinetobacter Species ◽  
E Coli ◽  
Lahore City

Background: The major faecal coliform is Escherichia coli which contaminates the drinking water from human and animal faecal waste. In developing regions drinking water is a vital source of microbiological pathogens. Multi-drug resistant (MDR) is defined as resistance to one or more antibiotic groups. An E. coli count greater than 4/dl in municipal drinking water is indicative of unacceptable fecal contamination. Aim: To find out the frequency of MDR E. coli in water system of Lahore, Pakistan. Methodology: Drinking water was collected from different towns of Lahore. The samples were processed using Membrane Filtration Technique. In the present study, Multidrug Resistant E.coli was isolated and antibiotic resistant pattern was seen against 16 most commonly antimicrobials, using Kirby Bauer disc diffusion method. Results: Total 100 water samples were collected, frequency of Escherichia coliisolated was 27% and frequency of MDR E.coli was 19%. The highest resistance showed by the organism towards Ampicillin (AMP) 21(81.48%), Augmentin (AMC), and Ceftazidime (CAZ) 14(51.85%) respectively. In this study also frequency of Extended Spectrum β-Lactamases were seen. Most common organisms isolated were E. coli 7% and Klebsiella 5%. Frequency of other coliforms isolated from drinking water other than E. coli was Klebsiella species 26%, Pseudomonas species 27%, Enterobacter 7%, Citrobacter species 8% and Acinetobacter species 5%. Conclusion: This study revealed that drinking water of Lahore city is heavilycontaminated with pathogenic microorganisms. A high proportion of antibiotic resistant is due to overuse of antibiotics, in patients with mild infections and secretion of these resistant bacteria from patients to environment. One of the reasons could be the mixing of sewage lines with drinking water supply. So, there is solely requirement for further studies for the identification of the sources for these contaminants. Keywords: Isolates, E. coli, Klebsiella, Multi-drug resistant (MDR)

An Improved Membrane Filtration Method for Enumeration of Faecal Coliforms and E. Coli by a Fluorogenic β-Glucuronidase Assay

1993 ◽  
Vol 27 (3-4) ◽  
pp. 267-270 ◽  
Author(s):  
M. T. Augoustinos ◽  
N. A. Grabow ◽  
B. Genthe ◽  
R. Kfir
Keyword(s):  
Escherichia Coli ◽  
Water Samples ◽  
Membrane Filtration ◽  
Faecal Coliforms ◽  
Environmental Waters ◽  
Filtration Method ◽  
E Coli ◽  
Wide Range ◽  
Pure Cultures ◽  
Glucuronidase Assay

A fluorogenic β-glucuronidase assay comprising membrane filtration followed by selective enumeration on m-FC agar at 44.5°C and further confirmation using tlie 4-metliylumbelliferyl-β-D-glucuronide (MUG) containing medium was evaluated for the detection of Escherichia coli in water. A total of 200 typical blue and non-typical blue colonies were isolated from sea and fresh water samples using initial selective enumeration on m-FC agar. Pure cultures of the selected colonies were further tested using the MUG assay and identified using the API 20E method. Of the colonies tested which were shown to be positive using the MUG assay 99.4% were Escherichia coli. The results of this study indicate the combination of the m-FC method followed by the MUG assay to be highly efficient for the selection and confirmation of E. coli from a wide range of environmental waters.

Tracking an Escherichia coli O157:H7–Contaminated Batch of Leafy Greens through a Pilot-Scale Fresh-Cut Processing Line

2014 ◽  
Vol 77 (9) ◽  
pp. 1487-1494 ◽  
Author(s):  
ANNEMARIE L. BUCHHOLZ ◽  
GORDON R. DAVIDSON ◽  
BRADLEY P. MARKS ◽  
EWEN C. D. TODD ◽  
ELLIOT T. RYSER
Keyword(s):  
Escherichia Coli ◽  
Membrane Filtration ◽  
Fluorescent Protein ◽  
Pilot Scale ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Leafy Greens ◽  
Iceberg Lettuce ◽  
Processing Line ◽  
Fresh Cut

Cross-contamination of fresh-cut leafy greens with residual Escherichia coli O157:H7–contaminated product during commercial processing was likely a contributing factor in several recent multistate outbreaks. Consequently, radicchio was used as a visual marker to track the spread of the contaminated product to iceberg lettuce in a pilot-scale processing line that included a commercial shredder, step conveyor, flume tank, shaker table, and centrifugal dryer. Uninoculated iceberg lettuce (45 kg) was processed, followed by 9.1 kg of radicchio (dip inoculated to contain a four-strain, green fluorescent protein–labeled nontoxigenic E. coli O157:H7 cocktail at 106 CFU/g) and 907 kg (2,000 lb) of uninoculated iceberg lettuce. After collecting the lettuce and radicchio in about 40 bags (~22.7 kg per bag) along with water and equipment surface samples, all visible shreds of radicchio were retrieved from the bags of shredded product, the equipment, and the floor. E. coli O157:H7 populations were quantified in the lettuce, water, and equipment samples by direct plating with or without prior membrane filtration on Trypticase soy agar containing 0.6% yeast extract and 100 ppm of ampicillin. Based on triplicate experiments, the weight of radicchio in the shredded lettuce averaged 614.9 g (93.6%), 6.9 g (1.3%), 5.0 g (0.8%), and 2.8 g (0.5%) for bags 1 to 10, 11 to 20, 21 to 30, and 31 to 40, respectively, with mean E. coli O157:H7 populations of 1.7, 1.2, 1.1, and 1.1 log CFU/g in radicchio-free lettuce. After processing, more radicchio remained on the conveyor (9.8 g; P < 0.05), compared with the shredder (8.3 g), flume tank (3.5 g), and shaker table (0.1 g), with similar E. coli O157:H7 populations (P > 0.05) recovered from all equipment surfaces after processing. These findings clearly demonstrate both the potential for the continuous spread of contaminated lettuce to multiple batches of product during processing and the need for improved equipment designs that minimize the buildup of residual product during processing.

scholarly journals Drinking water and diarrhoeal disease due to Escherichia coli

2003 ◽  
Vol 1 (2) ◽  
pp. 65-72 ◽  
Author(s):  
Paul R. Hunter
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Clinical Presentation ◽  
Diarrhoeal Disease ◽  
Central Place ◽  
E Coli ◽  
Related Disease ◽  
Direct Damage ◽  
Water Microbiology

Escherichia coli has had a central place in water microbiology for decades as an indicator of faecal pollution. It is only relatively recently that the role of E. coli as pathogen, rather than indicator, in drinking water has begun to be stressed. Interest in the role of E. coli as a cause of diarrhoeal disease has increased because of the emergence of E. coli O157:H7 and other enterohaemorrhagic E. coli, due to the severity of the related disease. There are enterotoxigenic, enteropathogenic, enterohaemorrhagic, enteroinvasive, enteroaggregative and diffusely adherent strains of E. coli. Each type of E. coli causes diarrhoeal disease through different mechanisms and each causes a different clinical presentation. Several of the types cause diarrhoea by the elaboration of one or more toxins, others by some other form of direct damage to epithelial cells. This paper discusses each of these types in turn and also describes their epidemiology, with particular reference to whether they are waterborne or not.

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