scholarly journals Use of tellurite for the selection of verocytotoxigenic Escherichia coli O157

1993 ◽  
Vol 39 (2) ◽  
pp. 155-158 ◽  
Author(s):  
P. M. Zadik ◽  
P. A. Chapman ◽  
C. A. Siddons
Keyword(s):  
Escherichia Coli ◽  
Escherichia Coli O157 ◽  
Selection Of

Selection of In Vivo Expressed Genes of Escherichia coli O157:H7 Strain EDL933 in Ground Meat under Elevated Temperature Conditions

2012 ◽  
Vol 75 (10) ◽  
pp. 1743-1750 ◽  
Author(s):  
ANDREA KROJ ◽  
HERBERT SCHMIDT
Keyword(s):  
Escherichia Coli ◽  
Elevated Temperatures ◽  
Genomic Library ◽  
Transport Processes ◽  
Enterohemorrhagic Escherichia Coli ◽  
Escherichia Coli O157 ◽  
Ground Meat ◽  
E Coli ◽  
Selection Of

Enterohemorrhagic Escherichia coli O157:H7 strains are important foodborne pathogens that are often transmitted to humans by the ingestion of raw or undercooked meat of bovine origin. To investigate adaptation of this pathogen during persistence and growth in ground meat, we established an in vivo expression technology model to identify genes that are expressed during growth in this food matrix under elevated temperatures (42°C). To improve on the antibiotic-based selection method, we constructed the promoter trap vector pAK-1, containing a promoterless kanamycin resistance gene. A genomic library of E. coli O157:H7 strain EDL933 was constructed in pAK-1 and used for promoter selection in ground meat. The 20 in vivo expressed genes identified were associated with transport processes, metabolism, macromolecule synthesis, and stress response. For most of the identified genes, only hypothetical functions could be assigned. The results of our study provide the first insights into the complex response of E. coli O157:H7 to a ground meat environment under elevated temperatures and establish a suitable vector for promoter studies or selection of in vivo induced promoters in foods such as ground meat.

scholarly journals CdTe/CdS quantum dot-labeled fluorescent immunochromatography test strips for rapid detection of Escherichia coli O157:H7

RSC Advances ◽  
2017 ◽  
Vol 7 (29) ◽  
pp. 17819-17823 ◽  
Author(s):  
Jinlu Yu ◽  
Jing Su ◽  
Jing Zhang ◽  
Xuetuan Wei ◽  
Ailing Guo
Keyword(s):  
Escherichia Coli ◽  
Quantum Dot ◽  
Foodborne Pathogens ◽  
Rapid Detection ◽  
High Sensitivity ◽  
Escherichia Coli O157 ◽  
Test Strips ◽  
Cds Quantum Dot ◽  
Selection Of

Immunochromatography test strips have been widely used to detect foodborne pathogens due to their high sensitivity, stability and specificity, and the selection of the label is an important factor.

In vitro selection of Escherichia coli O157:H7-specific RNA aptamer

2012 ◽  
Vol 417 (1) ◽  
pp. 414-420 ◽  
Author(s):  
Young Ju Lee ◽  
Seung Ryul Han ◽  
Jin-Soo Maeng ◽  
Yong-Jin Cho ◽  
Seong-Wook Lee
Keyword(s):  
Escherichia Coli ◽  
In Vitro Selection ◽  
Escherichia Coli O157 ◽  
Rna Aptamer ◽  
Selection Of

Comparison of Fecal versus Rectoanal Mucosal Swab Sampling for Detecting Escherichia coli O157:H7 in Experimentally Inoculated Cattle Used in Assessing Bacteriophage as a Mitigation Strategy

2008 ◽  
Vol 71 (4) ◽  
pp. 691-698 ◽  
Author(s):  
Y. D. NIU ◽  
Y. XU ◽  
T. A. McALLISTER ◽  
E. A. ROZEMA ◽  
T. P. STEPHENS ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Sampling Methods ◽  
Experimental Period ◽  
Immunomagnetic Separation ◽  
Sampling Procedure ◽  
Escherichia Coli O157 ◽  
Direct Plating ◽  
E Coli ◽  
Feedlot Steers ◽  
Selection Of

This study was conducted to compare fecal grab (FEC) and rectoanal mucosal swab (RAMS) techniques as sampling methods for surveillance of Escherichia coli O157:H7 in conjunction with administration of a mitigation therapy. The study was nested within a larger experiment that investigated bacteriophage as a preharvest strategy for controlling E. coli O157: H7 in feedlot steers. Samples (FEC and RAMS) were collected from 16 of the 32 feedlot steers (control and oral bacteriophage treatment; n = 8) involved in the mitigation study. All steers had been inoculated on day 0 with 1010 CFU of nalidixic acid–resistant E. coli O157:H7, and samples were collected on 16 occasions over the next 83 days. FEC samples were assessed by direct plating of serial dilutions in PBS, plus a 6-h enrichment and immunomagnetic separation when E. coli O157:H7 concentrations were below limits detectable by direct plating (i.e., <1 log CFU/g). All RAMS samples were assessed by enrichment and immunomagnetic separation. E. coli O157:H7 was detected more frequently (P < 0.01) by FEC than by RAMS. Overall, 213 of 256 samples were positive either by FEC or RAMS. Discrepancies between sampling techniques were observed in 63 of the 213 positive samples; FEC missed 11 samples that were positive by RAMS, and RAMS missed 52 of those positive by FEC (miss rates of 5.16 and 24.41%, respectively). Kappa values (0.36 to 0.45) indicated only fair to moderate agreement between FEC and RAMS results, but this agreement was higher at lower levels of E. coli O157:H7 shedding (later in the experimental period). Selection of sampling procedure could significantly influence the assessed merit during testing of potential strategies for controlling E. coli O157:H7 on the farm.

Selection of Recently Isolated Colicinogenic Escherichia coli Strains Inhibitory to Escherichia coli O157:H7

2002 ◽  
Vol 65 (9) ◽  
pp. 1381-1387 ◽  
Author(s):  
GERRY P. SCHAMBERGER ◽  
FRANCISCO DIEZ-GONZALEZ
Keyword(s):  
Escherichia Coli ◽  
Animal Species ◽  
Control Strategies ◽  
Repetitive Sequences ◽  
Proteinase K ◽  
Washout Rate ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Polymerase Chain ◽  
Selection Of

Escherichia coli strains were screened for their ability to inhibit E. coli O157:H7. An initial evaluation of 18 strains carrying previously characterized colicins determined that only colicin E7 inhibited all of the E. coli O157:H7 strains tested. A total of 540 strains that had recently been isolated from humans and nine different animal species (cats, cattle, chickens, deer, dogs, ducks, horses, pigs, and sheep) were tested by a flip-plating technique. Approximately 38% of these strains were found to inhibit noncolicinogenic E. coli K12 strains. The percentage of potentially colicinogenic E. coli per animal species ranged from 14% for horse isolates to 64% for sheep strains. Those isolates that inhibited E. coli K12 were screened against E. coli O157:H7, and 42 strains were found to be capable of inhibiting all 22 pathogenic strains tested. None of these 42 strains produced bacteriophages, and only 24 isolates inhibited serotype O157:H7 in liquid culture. The inhibitory activity of these strains was completely eliminated by treatment with proteinase K. When mixtures of these 24 colicinogenic strains were grown in anaerobic continuous culture, the four-strain E. coli O157:H7 population was reduced at a rate of 0.25 log10 cells per ml per h, which was fivefold faster than the washout rate. Two strains originally isolated from cat feces (F16) and human feces (H30) were identified by repetitive sequences polymerase chain reaction as the predominant isolates in continuous cultures. The results of this work indicate that animal species other than cattle can be sources of anti-O157 colicinogenic strains, and these results also lead to the identification of at least two isolates that could potentially be used in preharvest control strategies.

scholarly journals Antimicrobial Resistance of Escherichia coli O157 Isolated from Humans, Cattle, Swine, and Food

2002 ◽  
Vol 68 (2) ◽  
pp. 576-581 ◽  
Author(s):  
Carl M. Schroeder ◽  
Cuiwei Zhao ◽  
Chitrita DebRoy ◽  
Jocelyn Torcolini ◽  
Shaohua Zhao ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Shiga Toxin ◽  
Driving Force ◽  
Latex Agglutination ◽  
Escherichia Coli O157 ◽  
Production Environment ◽  
E Coli ◽  
Shiga Toxin Genes ◽  
Selection Of

ABSTRACT A total of 361 Escherichia coli O157 isolates, recovered from humans, cattle, swine, and food during the years 1985 to 2000, were examined to better understand the prevalence of antimicrobial resistance among these organisms. Based on broth microdilution results, 220 (61%) of the isolates were susceptible to all 13 antimicrobials tested. Ninety-nine (27%) of the isolates, however, were resistant to tetracycline, 93 (26%) were resistant to sulfamethoxazole, 61 (17%) were resistant to cephalothin, and 48 (13%) were resistant to ampicillin. Highest frequencies of resistance occurred among swine isolates (n = 70), where 52 (74%) were resistant to sulfamethoxazole, 50 (71%) were resistant to tetracycline, 38 (54%) were resistant to cephalothin, and 17 (24%) were resistant to ampicillin. Based on the presence of Shiga toxin genes as determined by PCR, 210 (58%) of the isolates were identified as Shiga toxin-producing E. coli (STEC). Among these, resistance was generally low, yet 21 (10%) were resistant to sulfamethoxazole and 19 (9%) were resistant to tetracycline. Based on latex agglutination, 189 (52%) of the isolates were identified as E. coli O157:H7, among which 19 (10%) were resistant to sulfamethoxazole and 16 (8%) were resistant to tetracycline. The data suggest that selection pressure imposed by the use of tetracycline derivatives, sulfa drugs, cephalosporins, and penicillins, whether therapeutically in human and veterinary medicine or as prophylaxis in the animal production environment, is a key driving force in the selection of antimicrobial resistance in STEC and non-STEC O157.

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.

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