scholarly journals Rapid Screening of Lanthipeptide Analogs via In-Colony Removal of Leader Peptides in Escherichia coli

2018 ◽  
Vol 140 (38) ◽  
pp. 11884-11888 ◽  
Author(s):  
Tong Si ◽  
Qiqi Tian ◽  
Yuhao Min ◽  
Linzixuan Zhang ◽  
Jonathan V. Sweedler ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Rapid Screening ◽  
Leader Peptides

scholarly journals The AIDA Autotransporter System Is Associated with F18 and Stx2e in Escherichia coli Isolates from Pigs Diagnosed with Edema Disease and Postweaning Diarrhea

2001 ◽  
Vol 8 (1) ◽  
pp. 143-149 ◽  
Author(s):  
Ulla Niewerth ◽  
Andreas Frey ◽  
Thomas Voss ◽  
Chantal Le Bouguénec ◽  
Georg Baljer ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Western Blot ◽  
Virulence Factors ◽  
Rapid Screening ◽  
Edema Disease ◽  
E Coli ◽  
Large Numbers ◽  
High Prevalence ◽  
Pcr Method ◽  
Postweaning Diarrhea

ABSTRACT Pathogenic Escherichia coli strains are known to cause edema disease (ED) and postweaning diarrhea (PWD) in piglets. Although the exact mechanisms of pathogenicity that lead to ED-PWD remain to be elucidated, E. coli-borne Shiga-like toxin and adhesion-mediating virulence factors such as F18 adhesin or F4 fimbriae are believed to play a central role in ED-PWD. In light of these observations we investigated whether another E. coliadhesin, the plasmid-encoded AIDA (adhesin involved in diffuse adherence) might also be present in ED-PWD-causing E. coli isolates. For rapid screening for the AIDA system in large numbers of isolates, a multiplex PCR method along with a duplex Western blot procedure was developed. When screening 104 strains obtained from pigs with or without ED-PWD, we observed a high prevalence of the AIDA operon in porcine E. coli isolates, with over 25% of all strains being AIDA positive, and we could demonstrate a significant association of the intact AIDA gene (orfB) with ED-PWD, while defects in orfB were associated with the absence of disease. Although our data hint toward a contribution of AIDA to ED-PWD, further studies will be necessary since the presence of the AIDA genes was also associated with the presence of the Shiga-like toxin and F18 adhesin genes, two reported virulence factors for ED-PWD.

scholarly journals Multiplex Real-Time Polymerase Chain Reaction for Simultaneous Quantification ofSalmonellaspp.,Escherichia coli, andStaphylococcus aureusin Different Food Matrices: Advantages and Disadvantages

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Amanda Teixeira Sampaio Lopes ◽  
George Rêgo Albuquerque ◽  
Bianca Mendes Maciel
Keyword(s):  
Escherichia Coli ◽  
Real Time ◽  
Limit Of Detection ◽  
Microbiological Quality ◽  
Rapid Screening ◽  
Multiplex Qpcr ◽  
Advantages And Disadvantages ◽  
Simultaneous Quantification ◽  
Polymerase Chain ◽  
Food Matrices

Quantitative real-time polymerase chain reactions (qPCRs) of the most prevalent bacteria causing foodborne diseases worldwide, such asSalmonellaspp.,Escherichia coli, andStaphylococcus aureus,can be an important tool for quantitative microbial risk assessment, which requires numerical data to determine the level of contamination at a specific stage of food production. However, most of qPCR assays described in the literature for these pathogens are qualitative; their objective is pathogen detection and not pathogen quantification. Thus, the aim of our work was to develop a qPCR for the simultaneous quantification ofSalmonellaspp.,E. coli, andS. aureusand to propose its use in the analysis of foods, as a tool for microbiological quality monitoring. For this, a multiplex qPCR was standardized for the simultaneous quantification of specific fragments of target genes (ssf,phoA, andnuc) corresponding to each one of the mentioned bacteria. The limit of detection of the technique was 13, 10, and 12 gene copies forssf,phoA, andnuc, respectively; standard curves showed R2> 0.99, with efficiencies ranging from 99 to 110%, and inter- and intraexperiment reproducibility presented a low coefficient of variation in all trials. This methodology was applied in different food matrices (milk, ground beef, and oyster meat), and the results were compared with official microbiological culture methodology and with ready-to-use test. Advantages and disadvantages of each methodology used in this study are pointed out. We suggest that this multiplex qPCR can be used as a rapid screening technique for the analysis of food microbiological quality.

A Rapid Test to Detect ST-producing Escherichia coli in Food

1992 ◽  
Vol 55 (10) ◽  
pp. 792-795
Author(s):  
KARSTEN FEHLHABER ◽  
RÜDIGER-THOMAS HESELER
Keyword(s):  
Escherichia Coli ◽  
Test Procedure ◽  
Brain Heart Infusion ◽  
Rapid Test ◽  
Food Samples ◽  
Food Sample ◽  
Rapid Screening ◽  
Infant Mouse ◽  
E Coli ◽  
Rapid Screening Test

Pasteurized milk, liquid egg, minced meat, and various salads were artificially contaminated with varying numbers of cells from six Escherichia coli (E. coli) strains able to produce heat-stable enterotoxins (ST). The ST-producing E. coli were detected by the following procedure within 24 h without isolation by cultivation. After enrichment of the food sample in GN broth (4 h at 37°C), the material was transferred to brain heart infusion broth, incubated (16–18 h at 37°C), centrifuged (20 min, 7000 g) and heated to 80°C for 10 min, the supernatant was tested with the infant mouse test. The sensitivity (= ratio of detectable E. coli per total microbial numbers in the food sample) of the test procedure was high even in many food samples with a considerable competitive microbial flora. The procedure was used to test 419 routine food samples. Enterotoxigenic bacteria were found in 7 samples of liquid egg and 4 samples of salad. The test is recommended as a rapid screening test in food control.

scholarly journals Same-Day Detection of Escherichia coli O157:H7 from Spinach by Using Electrochemiluminescent and Cytometric Bead Array Biosensors

2010 ◽  
Vol 76 (24) ◽  
pp. 8044-8052 ◽  
Author(s):  
Kelly M. Leach ◽  
Joyce M. Stroot ◽  
Daniel V. Lim
Keyword(s):  
Escherichia Coli ◽  
Pathogen Detection ◽  
Disease Outbreaks ◽  
Cytometric Bead Array ◽  
Rapid Screening ◽  
Testing Procedures ◽  
E Coli ◽  
Food Borne Illness ◽  
Time To Detection ◽  
Immunological Assays

ABSTRACT Contamination of fresh produce with Escherichia coli O157:H7 and other pathogens commonly causes food-borne illness and disease outbreaks. Thus, screening for pathogens is warranted, but improved testing procedures are needed to allow reproducible same-day detection of low initial contamination levels on perishable foods, and methods for detecting numerous pathogens in a single test are desired. Experimental procedures were developed to enable rapid screening of spinach for E. coli O157:H7 by using multiplex-capable immunological assays that are analyzed using biosensors. Detection was achieved using an automated electrochemiluminescent (ECL) assay system and a fluorescence-based cytometric bead array. Using the ECL system, less than 0.1 CFU of E. coli O157:H7 per gram of spinach was detected after 5 h of enrichment, corresponding to 6.5 h of total assay time. Using the cytometric bead array, less than 0.1 CFU/g was detected after 7 h of enrichment, with a total time to detection of less than 10 h. These results illustrate that both biosensor assays are useful for rapid detection of E. coli O157:H7 on produce in time frames that are comparable to or better than those of other testing formats. Both methods may be useful for multiplexed pathogen detection in the food industry and other testing situations.

scholarly journals Development of 11-Plex MOL-PCR Assay for the Rapid Screening of Samples for Shiga Toxin-Producing Escherichia coli

2016 ◽  
Vol 6 ◽  
Author(s):  
Travis A. Woods ◽  
Heather M. Mendez ◽  
Sandy Ortega ◽  
Xiaorong Shi ◽  
David Marx ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Rapid Screening ◽  
Pcr Assay

The purification from Escherichia coli of a protein relaxing superhelical DNA

1976 ◽  
Vol 54 (4) ◽  
pp. 301-306 ◽  
Author(s):  
M. G. Burrington ◽  
A. R. Morgan
Keyword(s):  
Escherichia Coli ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Rapid Screening ◽  
Intact Protein ◽  
Winding Number ◽  
Circular Dna ◽  
E Coli ◽  
The Individual ◽  
Negative Supercoils

The Escherichia coli omega protein was first described by Wang (Wang, J.C.: J. Mol. Biol. 55, 523–533 (1971)) as having the ability to relax supercoiled covalently-closed circular DNA by changing the topological winding number, α. We have developed a rapid assay for omega activity which has allowed us to purify the protein to homogeneity. It appears to be an αβ-ype subunit protein with a molecular weight of the intact protein of about 80 000 (determined by gel filtration) and of the individual subunits of 56 000 and 31 000 (sodium dodecyl sulfate polyacrylamide gels). We have confirmed Wang's observation that it only partly relaxes negative supercoils, and is not active on positive supercoils. Its characteristics with respect to pH, salts, temperature and chromatography are described. A method for rapid screening of E. coli for omega mutants is described.

scholarly journals Use of a Recombinant Strain of Mycobacterium avium Expressing β-Galactosidase To Evaluate the Activities of Antimycobacterial Agents inside Macrophages

2001 ◽  
Vol 45 (1) ◽  
pp. 356-358 ◽  
Author(s):  
Giuseppantonio Maisetta ◽  
Giovanna Batoni ◽  
Manuela Pardini ◽  
Antonella Boschi ◽  
Daria Bottai ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Mycobacterium Avium ◽  
Recombinant Strain ◽  
Antimicrobial Agents ◽  
Low Cost ◽  
Rapid Screening ◽  
Murine Macrophages ◽  
Antimycobacterial Agents

ABSTRACT A reliable and low-cost method that enables rapid screening of the activity exerted by new antimicrobial agents on intracellularly growingMycobacterium avium has been developed. To this aim, a recombinant (lacZ) strain of M. aviumexpressing the Escherichia coli β-galactosidase gene was used to evaluate, in murine macrophages, the susceptibility of M. avium to common antimycobacterial agents. β-Galactosidase levels, measured in the presence of each of the antibiotics tested, were closely correlated with the number of CFU recovered from theM. avium lacZ strain-infected macrophages.

Development of a rapid screening method for the detection of pathogenic Escherichia coli using a combination of Colilert® Quanti-Trays/2000 and PCR

2010 ◽  
Vol 10 (1) ◽  
pp. 7-13 ◽  
Author(s):  
K. B. Omar ◽  
N. Potgieter ◽  
T. G. Barnard
Keyword(s):  
Escherichia Coli ◽  
Internal Control ◽  
Screening Method ◽  
Rapid Screening ◽  
E Coli ◽  
Toilet Seat ◽  
Pathogenic Escherichia Coli ◽  
Wide Range ◽  
Polymerase Chain ◽  
Pcr Targeting

The use of culture based methods for the detection of Escherichia coli (E. coli) only gives information on the occurrence of E. coli and not pathogenicity of the organisms detected. To detect the both indicator and diarrhoeagenic E. coli (DEC) a method was developed using the Colilert® Quanti-Tray/2000 system and polymerase chain reaction (PCR). A total of 619 samples were collected from springs (33), boreholes (24), taps (5), rivers (36), streams (8), domestic storage containers (253), raw sewage (1), final effluents (5), stool (149), soil (5) and toilet seat swab (100) samples from various provinces in South Africa. E. coli was enumerated using the Colilert® Quanti-Tray's/2000 and DNA extracted from E. coli positive wells and used as template for a multiplex-PCR targeting genes specific to entero-pathogenic- (EPEC), entero-haemorrhagic- (EHEC), entero-invasive- (EIEC), entero-toxigenic (ETEC) and entero-aggregative E. coli (EAEC). The internal control was detected in 99% of positive E. coli samples. EAEC was detected in 17%, EIEC in 4%, ETEC in 11%, EHEC in 9% and EPEC in 21% of the E. coli positive samples. It is shown that this method can be used for the detection of DEC from a wide range of samples enriched with Colilert® Quanti-Tray's/2000.

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.

Sign in / Sign up

Export Citation Format

Share Document