scholarly journals Comparison of the Immunomagnetic Separation/Adenosine Triphosphate Rapid Method and the Modified mTEC Membrane-Filtration Method for Enumeration of Escherichia coli

2009 ◽  
Author(s):  
Amie M.G. Brady ◽  
Rebecca N. Bushon ◽  
Erin E. Bertke
Keyword(s):  
Escherichia Coli ◽  
Rapid Method ◽  
Adenosine Triphosphate ◽  
Membrane Filtration ◽  
Immunomagnetic Separation ◽  
Filtration Method

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.

scholarly journals Application of quantitative real-time PCR compared to filtration methods for the enumeration of Escherichia coli in surface waters within Vietnam

2016 ◽  
Vol 15 (1) ◽  
pp. 155-162 ◽  
Author(s):  
Pierangeli G. Vital ◽  
Nguyen Thi Van Ha ◽  
Le Thi Hong Tuyet ◽  
Kenneth W. Widmer
Keyword(s):  
Escherichia Coli ◽  
Real Time ◽  
Surface Waters ◽  
Real Time Pcr ◽  
Membrane Filtration ◽  
Quantitative Real Time Pcr ◽  
Wet Season ◽  
Culture Methods ◽  
Fecal Indicator ◽  
Filtration Method

Surface water samples in Vietnam were collected from the Saigon River, rural and suburban canals, and urban runoff canals in Ho Chi Minh City, Vietnam, and were processed to enumerate Escherichia coli. Quantification was done through membrane filtration and quantitative real-time polymerase chain reaction (PCR). Mean log colony-forming unit (CFU)/100 ml E. coli counts in the dry season for river/suburban canals and urban canals were log 2.8 and 3.7, respectively, using a membrane filtration method, while using Taqman quantitative real-time PCR they were log 2.4 and 2.8 for river/suburban canals and urban canals, respectively. For the wet season, data determined by the membrane filtration method in river/suburban canals and urban canals samples had mean counts of log 3.7 and 4.1, respectively. While mean log CFU/100 ml counts in the wet season using quantitative PCR were log 3 and 2, respectively. Additionally, the urban canal samples were significantly lower than those determined by conventional culture methods for the wet season. These results show that while quantitative real-time PCR can be used to determine levels of fecal indicator bacteria in surface waters, there are some limitations to its application and it may be impacted by sources of runoff based on surveyed samples.

scholarly journals Recovery and Detection of Escherichia coli O157:H7 in Surface Water, Using Ultrafiltration and Real-Time PCR

2009 ◽  
Vol 75 (11) ◽  
pp. 3593-3597 ◽  
Author(s):  
Bonnie Mull ◽  
Vincent R. Hill
Keyword(s):  
Escherichia Coli ◽  
Surface Water ◽  
Real Time ◽  
Real Time Pcr ◽  
Membrane Filtration ◽  
Analytical Techniques ◽  
Immunomagnetic Separation ◽  
Treated Wastewater ◽  
Sample Collection ◽  
Multiple Pcr

ABSTRACT Enterohemorrhagic Escherichia coli O157:H7 (EHEC O157:H7) outbreaks have revealed the need for improved analytical techniques for environmental samples. Ultrafiltration (UF) is increasingly recognized as an effective procedure for concentrating and recovering microbes from large volumes of water and treated wastewater. This study describes the application of hollow-fiber UF as the primary step for concentrating EHEC O157:H7 seeded into 40-liter samples of surface water, followed by an established culture/immunomagnetic-separation (IMS) method and a suite of real-time PCR assays. Three TaqMan assays were used to detect the stx1, stx2, and rfbE gene targets. The results from this study indicate that approximately 50 EHEC O157:H7 cells can be consistently recovered from a 40-liter surface water sample and detected by culture and real-time PCR. Centrifugation was investigated and shown to be a viable alternative to membrane filtration in the secondary culture/IMS step when water quality limits the volume of water that can be processed by a filter. Using multiple PCR assay sets to detect rfbE, stx1, and stx2 genes allowed for specific detection of EHEC O157:H7 from strains that do not possess all three genes. The reported sample collection and analysis procedure should be a sensitive and effective tool for detecting EHEC O157:H7 in response to outbreaks of disease associated with contaminated water.

In-House Validation of a Rinse–Membrane Filtration Method for Processing Fresh Produce Samples for Downstream Cultural Detection of Salmonella, Escherichia coli O157:H7, and Listeria

2020 ◽  
Vol 83 (9) ◽  
pp. 1592-1597
Author(s):  
LAURA E. TIJERINA-RODRÍGUEZ ◽  
LUISA SOLÍS-SOTO ◽  
NORMA HEREDIA ◽  
JUAN S. LEÓN ◽  
LEE-ANN JAYKUS ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Membrane Filtration ◽  
Pathogen Detection ◽  
Fresh Produce ◽  
Bacterial Pathogen ◽  
Relative Sensitivity ◽  
Good Alternative ◽  
Detection Methods ◽  
Filtration Method ◽  
Relative Specificity

ABSTRACT More efficient sampling and detection methods of pathogens on fresh produce are needed. The purpose of this study was to compare a novel rinse–membrane filtration method (RMFM) to a more traditional sponge rubbing or stomaching method in processing jalapeño peppers and cantaloupe samples for detection of Escherichia coli, Salmonella enterica, and Listeria monocytogenes. For jalapeño peppers inoculated with 106, 104, and 102 CFU of each pathogen and cantaloupes inoculated at 106 and 104 CFU, all pathogens were detected in all (100%) samples by RMFM at a 10-mL filtration volume, as well as by the stomacher and sponge rubbing methods. However, for cantaloupe inoculated at 102 CFU, detection differed by pathogen: S. enterica (20% RMFM, 60% stomacher, and 20% sponge), L. monocytogenes (40% RMFM, 60% stomacher, and 20% sponge), and E. coli O157:H7 (100% RMFM, 75% stomacher, and 75% sponge). When RMFM was compared with the other methods, in accordance with guidelines in the International Organization for Standardization 16140:2003 protocol, it produced values >95% in relative accuracy, relative specificity, and relative sensitivity. Overall, the RMFM performed similar to or better than the homogenization and sponge surface rubbing methods and is a good alternative for processing large numbers of produce samples for bacterial pathogen detection.

Antibody-Direct Epifluorescent Filter Technique and Immunomagnetic Separation for 10-h Screening and 24-h Confirmation of Escherichia coli O157:H7 in Beef

1996 ◽  
Vol 59 (10) ◽  
pp. 1072-1075 ◽  
Author(s):  
LAWRENCE RESTAINO ◽  
H. JEFFREY CASTILLO ◽  
DIANA STEWART ◽  
MARY LOU TORTORELLO
Keyword(s):  
Escherichia Coli ◽  
Membrane Filtration ◽  
Immunomagnetic Separation ◽  
Rapid Screening ◽  
Epifluorescence Microscopy ◽  
Objective Lens ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Filter Technique ◽  
Direct Epifluorescent Filter Technique

Rapid screening of beef for the presence of Escherichia coli O157:H7 was shown to be feasible using a 10-h enrichment in modified buffered peptone water and the antibody-direct epifluorescent filter technique (Ab-DEFT). The Ab-DEFT involved membrane filtration, fluorescent antibody staining and epifluorescence microscopy and was accomplished in less than 1 h. The procedure allowed detection of the pathogen artificially inoculated into beef patties at 0.1 CFU/g. The 10-h nonselective enrichment broth supported rapid growth, which provided sufficient numbers of cells for a positive determination by the Ab-DEFT after fewer than 10 microscope fields were scanned using a 40× objective lens. Immunomagnetic separation using anti-E. coli O157 Dynabeads® was used to confirm presumptively positive cultures within 24 h. The ease and rapidity of the Ab-DEFT may provide a substantial time and cost savings to the beef industry for screening beef for the presence of E. coli O157:H7.

Antimicrobial Resistance and Genetic Profiling of Escherichia coli from a Commercial Beef Packing Plant†

2006 ◽  
Vol 69 (7) ◽  
pp. 1508-1513 ◽  
Author(s):  
MUEEN ASLAM ◽  
CARA SERVICE
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Membrane Filtration ◽  
Antimicrobial Agents ◽  
Random Amplified Polymorphic Dna ◽  
Ground Beef ◽  
Resistant Bacteria ◽  
Filtration Method ◽  
E Coli ◽  
Beef Processing

The objective of this study was to investigate the extent of antimicrobial resistance and to genetically characterize resistant Escherichia coli recovered from a commercial beef packing plant. E. coli isolates were recovered by a hydrophobic grid membrane filtration method by direct plating on SD-39 medium. A total of 284 isolates comprising 71, 36, 55, 52, and 70 isolates from animal hides, washed carcasses, conveyers, beef trimmings, and ground beef, respectively, were analyzed. The susceptibility of E. coli isolates to 15 antimicrobial agents was evaluated with an automated broth microdilution system, and the genetic characterization of these isolates was performed by the random amplified polymorphic DNA (RAPD) method. Of the 284 E. coli isolates, 56% were sensitive to all 15 antimicrobial agents. Resistance to tetracycline, ampicillin, and streptomycin was observed in 38, 9, and 6% of the isolates, respectively. Resistance to one or more antimicrobial agents was observed in 51% of the E. coli isolates recovered from the hides but in only 25% of the E. coli from the washed carcasses. Resistance to one or more antimicrobial agents was observed in 49, 50, and 37% of the isolates recovered from conveyers, beef trimmings, and ground beef, respectively. The RAPD pattern data showed that the majority of resistant E. coli isolates were genetically diverse. Only a few RAPD types of resistant strains were shared among various sample sources. The results of this study suggest that antimicrobial-resistant E. coli isolates were prevalent during all stages of commercial beef processing and that considerably higher numbers of resistant E. coli were present on conveyers, beef trimmings, and ground beef than on dressed carcasses. This stresses the need for improving hygienic conditions during all stages of commercial beef processing and meatpacking to avoid the risks of transfer of antimicrobial-resistant bacteria to humans.

Removal of Escherichia coli and Enterococcus faecalis after Hand Washing with Antimicrobial and Nonantimicrobial Soap and Persistence of These Bacteria in Rinsates

2017 ◽  
Vol 80 (10) ◽  
pp. 1670-1675 ◽  
Author(s):  
J. Pérez-Garza ◽  
S. García ◽  
N. Heredia
Keyword(s):  
Escherichia Coli ◽  
Enterococcus Faecalis ◽  
Membrane Filtration ◽  
Chlorhexidine Gluconate ◽  
Hand Washing ◽  
Distilled Water ◽  
Antimicrobial Compounds ◽  
Filtration Method ◽  
E Coli ◽  
Reducing Bacteria

ABSTRACT Foodhandlers are important sources of contamination in the agricultural environment. This study was conducted (i) to evaluate the activity of antimicrobial soaps against Escherichia coli and Enterococcus faecalis using a hand washing model with soiled hands and (ii) to determine the survival and persistence of these bacteria in rinsates. Sterilized agricultural soil from tomato and pepper farms was inoculated with E. coli or E. faecalis at 103 or 106 CFU/g. Decontaminated hands were placed in contact with contaminated soil for 2 min and were then washed with soaps with or without antimicrobial compounds (citric extracts, chloroxylenol, triclosan, or chlorhexidine gluconate). As the control, hands were washed with sterile distilled water. The levels of bacteria remaining on the hands and recovered from the rinsates were determined using a membrane filtration method and selective media. Antimicrobial soaps removed levels of E. coli similar to those removed by distilled water and nonantimicrobial soap on hands contaminated with E. coli at 103 CFU/g. However, when hands were contaminated with E. coli at 106 CFU/g, more E. coli was removed with the chlorhexidine gluconate soap. When hands were contaminated with E. faecalis at 103 CFU/g, bacteria were removed more effectively with soaps containing chloroxylenol or chlorhexidine gluconate. When hands were contaminated with E. faecalis at 106 CFU/g, all of the antimicrobial soaps were more effective for removing the bacteria than were distilled water and nonantimicrobial soap. E. coli grew in all of the hand washing rinsates except that containing triclosan, whereas E. faecalis from the 106 CFU/g treatments grew in rinsates containing chlorhexidine gluconate and in the distilled water rinsates. Washing with antimicrobial soap was more effective for reducing bacteria on soiled hands than was washing with water or nonantimicrobial soap. However, persistence or growth of bacteria in these rinsates poses health risks.

Is TBX agar a suitable medium for monitoring Escherichia coli in bathing water using the membrane filtration method?

2019 ◽  
Vol 191 (9) ◽  
Author(s):  
Slaven Jozić ◽  
Darija Vukić Lušić ◽  
Ante Aljinović ◽  
Wendy Vlakančić ◽  
Arijana Cenov ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Membrane Filtration ◽  
Filtration Method ◽  
Suitable Medium ◽  
Bathing Water
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