Fingerprints of resistant Escherichia coli O157:H7 from vegetables and environmental samples

2017 ◽  
Vol 98 (1) ◽  
pp. 80-86
Author(s):  
Grace Onyukwo Abakpa ◽  
Veronica J Umoh ◽  
Sijam Kamaruzaman ◽  
Mark Ibekwe
Keyword(s):  
Escherichia Coli ◽  
Environmental Samples ◽  
Escherichia Coli O157

Potential pitfalls in the quantitative molecular detection ofEscherichia coliO157:H7 in environmental matrices

2006 ◽  
Vol 52 (5) ◽  
pp. 482-488 ◽  
Author(s):  
Rebekka R.E Artz ◽  
Lisa M Avery ◽  
Davey L Jones ◽  
Ken Killham
Keyword(s):  
Escherichia Coli ◽  
Real Time ◽  
Real Time Pcr ◽  
Environmental Samples ◽  
Detection Sensitivity ◽  
Escherichia Coli O157 ◽  
Soil System ◽  
E Coli ◽  
Animal Wastes ◽  
Pcr Assays

The detection sensitivity and potential interference factors of a commonly used assay based on real-time polymerase chain reaction (PCR) for Escherichia coli O157:H7 using eae gene-specific primers were assessed. Animal wastes and soil samples were spiked with known replicate quantities of a nontoxigenic strain of E. coli O157:H7 in a viable or dead state and as unprotected DNA. The detection sensitivity and accuracy of real-time PCR for E. coli O157:H7 in animal wastes and soil is low compared to enrichment culturing. Nonviable cells and unprotected DNA were shown to produce positive results in several of the environmental samples tested, leading to potential overestimates of cell numbers due to prolonged detection of nonviable cells. This demonstrates the necessity for the specific calibration of real-time PCR assays in environmental samples. The accuracy of the eae gene–based detection method was further evaluated over time in a soil system against an activity measurement, using the bioluminescent properties of an E. coli O157:H7 Tn5luxCDABE construct. The detection of significant numbers of viable but nonculturable (VBNC) as well as nonviable and possibly physically protected cells as shown over a period of 90 days further complicates the use of real-time PCR assays for quick diagnostics in environmental samples and infers that enrichment culturing is still required for the final verification of samples found positive by real-time PCR methods.Key words: Escherichia coli O157:H7, real-time PCR, animal waste, soil, VBNC.

Methods Used for Detection and Recovery of Escherichia coli O157:H7 Associated with a Food-Borne Disease Outbreak†

1995 ◽  
Vol 58 (6) ◽  
pp. 597-603 ◽  
Author(s):  
J. L.JOHNSON ◽  
B. E. ROSE ◽  
A. K. SHARAR ◽  
G. M. RANSOM ◽  
C. P. LATTUADA ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Environmental Samples ◽  
Disease Outbreak ◽  
Screening Methods ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Food Borne ◽  
Quantitative Analyses ◽  
Inspection Service ◽  
Positive Results

The current Food Safety and Inspection Service method for detection and recovery of Escherichia coli O157:H7, (including modified EC broth with novobiocin (mEC+n) and a direct blot ELISA). was used to analyze beef and environmental samples during an investigation of a food-borne disease outbreak attributed to consumption of undercooked hamburger patties. Double-modified trypticase soy broth (dmTSB) and a commercially available dipstick immunoassay were also used to improve detection/recovery of E. coli O157:H7. A total of 1,115 beef and environmental samples was screened with the direct blot ELISA and the dipstick immunoassay; 178 presumptive-positive samples (by either or both of the screening methods) were subjected to recovery/isolation procedures. Toxigenic E. coli O157:H7 was recovered from 45 samples: 40 hamburger-patty samples produced on the epidemiologically identified date, 3 hamburger-patty samples produced on another date, and 2 beef briskets. The organism was not recovered from environmental samples. Limited quantitative analyses indicated that contaminated hamburger patties contained fewer than 4.3 CFU of E. coli O157:H7 per g. Atypical, toxigenic ornithine decarboxylase–negative E. coli O157:H7 and nontoxigenic sorbitol-positive E. coli O157:H29 were also recovered. Both enrichment broths gave strong positive reactions with the two immunoassay screening methods, but E. coli O157:H7 was recovered more often from mEC+n broth than from dmTSB. Both screening methods gave positive results for 44 of the 45 beef samples found to contain E. coli O157:H7. False-positive results were frequently observed with both screening methods.

scholarly journals Investigating the Whole-Genome Sequence of a New Locus of Enterocyte Effacement-Positive Shiga Toxin-Producing Escherichia coli O157:H7 Strain Isolated from River Water

2020 ◽  
Vol 9 (12) ◽  
Author(s):  
Yujie Zhang ◽  
Yen-Te Liao ◽  
Alexandra Salvador ◽  
Xiaohong Sun ◽  
Vivian C. H. Wu
Keyword(s):  
Escherichia Coli ◽  
Genome Sequence ◽  
Mississippi River ◽  
Shiga Toxin ◽  
Environmental Samples ◽  
Whole Genome Sequence ◽  
Whole Genome ◽  
Escherichia Coli O157 ◽  
Content Type ◽  
Enterocyte Effacement

Diverse Shiga toxin-producing Escherichia coli (STEC) strains have been isolated from several environmental samples. Rivers are associated with the distribution of STEC pathogens in the environment. Thus, we report the complete genome sequence of a locus of enterocyte effacement (LEE)-positive STEC O157:H7 strain isolated from the Mississippi River.

scholarly journals Differences in Colonization and Shedding Patterns after Oral Challenge of Cattle with Three Escherichia coli O157:H7 Strains

2012 ◽  
Vol 78 (22) ◽  
pp. 8045-8055 ◽  
Author(s):  
Megan J. Kulow ◽  
Tina K. Gonzales ◽  
Kelly M. Pertzborn ◽  
James Dahm ◽  
Bret A. Miller ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
High Throughput ◽  
Real Time Pcr ◽  
Environmental Samples ◽  
Oral Challenge ◽  
Escherichia Coli O157 ◽  
Content Type ◽  
E Coli ◽  
Group 4 ◽  
Group 3

ABSTRACTExperimental oral challenge studies with three different genotypes ofEscherichia coliO157:H7 were conducted in cattle to determine the genotype-specific variability in shedding frequencies and concentrations and the frequency and extent of contamination of the environment. The results indicated that theE. coliO157:H7 genotype and ecological origin maybe important factors for the occurrence and concentration in the cattle host. Four groups of six young Holstein steers each were orally challenged with 106CFU of one of threeE. coliO157:H7 strains: FRIK 47 (groups 1 and 2), FRIK 1641 (group 3), and FRIK 2533 (group 4). Recto-anal mucosal swabs (RAMS) and environmental samples were taken on alternate days over 30 days. The numbers ofE. coliO157:H7 cells and genericE. colicells per sample were determined. Also, the presence and absence of 28 gene targets were determined for 2,411 isolates using high-throughput real-time PCR. Over the study period, strains FRIK 47, FRIK 1641, and FRIK 2533 were detected in 52%, 42%, and 2% of RAMS, respectively. Environmental detection of the challenge strains was found mainly in samples of the hides and pen floors, with strains FRIK 47, FRIK 1641, and FRIK 2533 detected in 22%, 27%, and 0% of environmental samples, respectively. Based on the panel of 28 gene targets, genotypes of enterohemorrhagicE. coli(EHEC) and genericE. colifrom the experimental samples were clustered into three subgroups. In conclusion, the results suggested that the type and intensity of measures to control this pathogen at the preharvest level may need to be strain specific.

Bedeutung von Escherichia coli O157 beim Schlachtschaf in der Schweiz

2006 ◽  
Vol 148 (6) ◽  
pp. 289-295 ◽  
Author(s):  
C. Zweifel ◽  
M. Kaufmann ◽  
J. Blanco ◽  
R. Stephan
Keyword(s):  
Escherichia Coli ◽  
Escherichia Coli O157

Molecular profiling and antimicrobial susceptibility of Escherichia coli O157:H7 isolated in Bulgaria

2020 ◽  
Vol 23 (3) ◽  
pp. 310-318
Author(s):  
K. Koev ◽  
T. Stoyanchev ◽  
G. Zhelev ◽  
P. Marutsov ◽  
K. Gospodinova ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Escherichia Coli O157 ◽  
Acid Sensitivity ◽  
Lower Extent ◽  
Phenotype Analysis ◽  
Anal Swab ◽  
Amoxicillin Clavulanic Acid ◽  
Primary Identification ◽  
Stx1 Gene ◽  
Cattle Farms

The purpose of this study was to detect the presence of shiga-toxin producing Escherichia coli (STEC) in faeces of healthy dairy cattle and to determine the sensitivity of isolates to several anti­microbial drugs. A total of 1,104 anal swab samples originating from 28 cattle farms were examined. After the primary identification, 30 strains were found to belong to serogroup О157. By means of conventional multiplex PCR, isolates were screened for presence of resistance genes stx1, stx2 and eaeА. Twenty-nine strains possesses amplicons with a size corresponding to genes stx2 and eaeA, one had amplicons also for the stx1 gene and one lacked amplicons of all three genes. Twenty-eight strains demonstrated amplicons equivalent to gene H7. The results from phenotype analysis of resistance showed preserved sensitivity to ceftriaxone, ceftazidime, cefotaxime, cephalothin, streptomycin, gentamicin, tetracycline, enrofloxacin and combinations sulfamethoxazole/trimethoprim and amoxicillin/clavulanic acid. Sensitivity to ampicillin was relatively preserved, although at a lower extent.

Sign in / Sign up

Export Citation Format

Share Document