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

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.

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.

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.

scholarly journals Comparison of Membrane Filtration and Multiple-Tube Fermentation by the Colilert and Enterolert Methods for Detection of Waterborne Coliform Bacteria, Escherichia coli, and Enterococci Used in Drinking and Bathing Water Quality Monitoring in Southern Sweden

1998 ◽  
Vol 64 (8) ◽  
pp. 3079-3083 ◽  
Author(s):  
Karl F. Eckner
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Water Samples ◽  
Membrane Filtration ◽  
Water Quality Monitoring ◽  
Coliform Bacteria ◽  
Southern Sweden ◽  
Standard Methods ◽  
Bathing Water ◽  
Drinking Water Samples

ABSTRACT A total of 338 water samples, 261 drinking water samples and 77 bathing water samples, obtained for routine testing were analyzed in duplicate by Swedish standard methods using multiple-tube fermentation or membrane filtration and by the Colilert and/or Enterolert methods. Water samples came from a wide variety of sources in southern Sweden (Skåne). The Colilert method was found to be more sensitive than Swedish standard methods for detecting coliform bacteria and of equal sensitivity for detecting Escherichia coli when all drinking water samples were grouped together. Based on these results, Swedac, the Swedish laboratory accreditation body, approved for the first time in Sweden use of the Colilert method at this laboratory for the analysis of all water sources not falling under public water regulations (A-krav). The coliform detection study of bathing water yielded anomalous results due to confirmation difficulties. E. coli detection in bathing water was similar by both the Colilert and Swedish standard methods as was fecal streptococcus and enterococcus detection by both the Enterolert and Swedish standard methods.

Repeatability of the Petrifilm™ HEC Test and Agreement with a Hydrophobic Grid Membrane Filtration Method for the Enumeration of Escherichia coli O157:H7 on Beef Carcasses

1998 ◽  
Vol 61 (4) ◽  
pp. 402-408 ◽  
Author(s):  
CHRISTINE A. POWER ◽  
SCOTT A. MCEWEN ◽  
ROGER P. JOHNSON ◽  
MOHAMED M. SHOUKRI ◽  
KRIS RAHN ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Membrane Filtration ◽  
Ease Of Use ◽  
Escherichia Coli O157 ◽  
Filtration Method ◽  
E Coli ◽  
Beef Carcasses ◽  
Compact Size ◽  
Pure Cultures ◽  
Smac Method

The Petrifilm™ HEC test (3M Canada Inc., London, Ontario), a quantitative microbiological test for Escherichia coli O157:H7, was evaluated for its performance as a beef-carcass monitoring test. Test repeatability and agreement with an E. coli O157:H7 detection method using a hydrophobic grid membrane filter (HGMF) overlaid onto cefixime–tellurite–sorbitol MacConkey agar (CT-SMAC) followed by a latex agglutination test for the O157 antigen were determined by using pure cultures of E. coli O157:H7, beef samples experimentally contaminated with bovine feces containing E. coli O157:H7, and naturally contaminated beef carcasses of unknown E. coli O157:H7 status from a local abattoir. The Petrifilm™ HEC test showed excellent repeatability and excellent agreement with the HGMF–CT-SMAC method when test samples were obtained from pure cultures and experimentally contaminated meat. All 125 naturally contaminated beef carcasses surveyed were negative for E. coli O157:H7 with both microbial methods. The Petrifilm™ HEC test, however, demonstrated a significantly lower proportion of cross-reactive organisms (false-positive reactions) than the HGMF–CT-SMAC method. Given the performance of this test coupled with its ease of use and compact size, it shows considerable promise for carcass testing where abattoir laboratory facilities are limited and as a substitute for more complex laboratory testing methods used in established laboratories.

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