Use of Multiple-Locus Variable-Number Tandem Repeat Analysis to Evaluate Escherichia coli O157 Subtype Distribution and Transmission Dynamics Following Natural Exposure on a Closed Beef Feedlot Facility

2013 ◽  
Vol 10 (10) ◽  
pp. 827-834 ◽  
Author(s):  
Michele L. Williams ◽  
David L. Pearl ◽  
Katherine E. Bishop ◽  
Jeffrey T. LeJeune
Keyword(s):  
Escherichia Coli ◽  
Tandem Repeat ◽  
Variable Number Tandem Repeat ◽  
Variable Number ◽  
Transmission Dynamics ◽  
Escherichia Coli O157 ◽  
Multiple Locus ◽  
Repeat Analysis ◽  
Natural Exposure ◽  
Subtype Distribution

scholarly journals Multiple-locus variable-number tandem repeat analysis for strain discrimination of non-O157 Shiga toxin-producing Escherichia coli

2016 ◽  
Vol 125 ◽  
pp. 70-80 ◽  
Author(s):  
Chris Timmons ◽  
Eija Trees ◽  
Efrain M. Ribot ◽  
Peter Gerner-Smidt ◽  
Patti LaFon ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Tandem Repeat ◽  
Shiga Toxin ◽  
Variable Number Tandem Repeat ◽  
Variable Number ◽  
Multiple Locus ◽  
Repeat Analysis

Microbiological Effects of a Routine Treatment for Decontaminating Hide-On Carcasses at a Large Beef Packing Plant

2015 ◽  
Vol 78 (2) ◽  
pp. 256-263 ◽  
Author(s):  
XIANQIN YANG ◽  
MADHU BADONI ◽  
FRANCES TRAN ◽  
COLIN O. GILL
Keyword(s):  
Escherichia Coli ◽  
Tandem Repeat ◽  
Variable Number Tandem Repeat ◽  
Variable Number ◽  
Routine Treatment ◽  
Multiple Locus ◽  
E Coli ◽  
Repeat Analysis ◽  
Before And After

To investigate the microbiological effects of a hide-on carcass decontaminating treatment recently implemented at a beef packing plant, carcasses undergoing routine processing at the plant were sampled during successive periods in January/February, April/May, and September/October. During each period, samples were collected from carcasses before and after the decontamination of hide-on carcasses, after skinning, before decontamination of the skinned carcasses, and at the end of the carcass dressing process. At each stage of processing during each period, samples were obtained by swabbing an area of 1,000 cm2 on each of 25 carcasses. Aerobes, coliforms, and Escherichia coli were enumerated. In most samples, coliforms were predominantly E. coli. In all three periods, the log mean numbers of aerobes and E. coli recovered from hides before decontamination were between 6.6 and 6.8 and between 5.3 and 5.9 log CFU/1,000 cm2, respectively. The log mean numbers of aerobes recovered from decontaminated hides were 6.6 log CFU/1,000 cm2 in January/February and April/May but 5.4 log CFU/1,000 cm2 in September/October. The log total numbers of E. coli recovered from decontaminated hides in January/February and April/May were 2.4 and 3.8 log CFU/25,000 cm2, respectively, but no E. coli was recovered from such carcasses in September/October. Log total numbers of aerobes and E. coli recovered from skinned or dressed carcasses were mostly >4 and between 1 and 2 log CFU/25,000 cm2, respectively. Typing of 480 E. coli isolates by multiple-locus variable-number tandem repeat analysis (MLVA) identified 218 MLVA types. Most isolates recovered from carcasses in different periods or at different stages of processing were of different MLVA types. However, small numbers of MLVA types were recovered in more than one period or from both hides before and after decontamination and skinned or dressed carcasses. The findings show that the hide-decontaminating treatment disrupted the usual transfer of E. coli from hides to meat surfaces during carcass skinning.

Inter-laboratory comparison of multi-locus variable-number tandem repeat analysis (MLVA) for verocytotoxin-producing Escherichia coli O157 to facilitate data sharing

2014 ◽  
Vol 143 (1) ◽  
pp. 104-107 ◽  
Author(s):  
A. HOLMES ◽  
N. PERRY ◽  
G. WILLSHAW ◽  
M. HANSON ◽  
L. ALLISON
Keyword(s):  
Escherichia Coli ◽  
Tandem Repeat ◽  
Variable Number Tandem Repeat ◽  
Variable Number ◽  
Escherichia Coli O157 ◽  
Consensus Guidelines ◽  
International Consensus ◽  
Repeat Analysis ◽  
Repeat Units ◽  
International Consensus Guidelines

SUMMARYMulti-locus variable number tandem repeat analysis (MLVA) is used in clinical and reference laboratories for subtyping verocytotoxin-producing Escherichia coli O157 (VTEC O157). However, as yet there is no common allelic or profile nomenclature to enable laboratories to easily compare data. In this study, we carried out an inter-laboratory comparison of an eight-loci MLVA scheme using a set of 67 isolates of VTEC O157. We found all but two isolates were identical in profile in the two laboratories, and repeat units were homogeneous in size but some were incomplete. A subset of the isolates (n = 17) were sequenced to determine the actual copy number of representative alleles, thereby enabling alleles to be named according to international consensus guidelines. This work has enabled us to realize the potential of MLVA as a portable, highly discriminatory and convenient subtyping method.

scholarly journals Multilocus Variable-Number Tandem Repeat Analysis Distinguishes Outbreak and Sporadic Escherichia coli O157:H7 Isolates

2004 ◽  
Vol 42 (2) ◽  
pp. 940-940
Author(s):  
A. C. Noller ◽  
M. C. McEllistrem ◽  
A. G. F. Pacheco ◽  
D. J. Boxrud ◽  
L. H. Harrison
Keyword(s):  
Escherichia Coli ◽  
Tandem Repeat ◽  
Variable Number Tandem Repeat ◽  
Variable Number ◽  
Escherichia Coli O157 ◽  
Repeat Analysis

Escherichia coli O157:H7 Outbreak Associated with Restaurant Beef Grinding

2015 ◽  
Vol 78 (7) ◽  
pp. 1272-1279 ◽  
Author(s):  
LAUREN M. TORSO ◽  
RONALD E. VOORHEES ◽  
STEPHEN A. FOREST ◽  
ANDREW Z. GORDON ◽  
SHARON A. SILVESTRI ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Tandem Repeat ◽  
Gel Electrophoresis ◽  
Variable Number Tandem Repeat ◽  
Ground Beef ◽  
Variable Number ◽  
Pulsed Field Gel Electrophoresis ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Repeat Analysis

Escherichia coli O157:H7 is a common cause of foodborne illness in the United States. Beef ground at establishments regulated by the U.S. Department of Agriculture, Food Safety and Inspection Service is routinely tested for E. coli O157:H7. Prior to December 2013, boxed beef product (wholesale cuts of beef, such as beef loin, packaged into bags and boxed for shipping) was not always tested for this pathogen. Downstream processors or retailers may grind the product; and, if the ground beef is not cooked to the recommended temperature, pathogens on the exterior of the beef introduced to the interior through grinding may survive. On 18 October 2013, the Allegheny County Health Department identified two E. coli O157:H7 cases, both of whom were food handlers at restaurant A, a restaurant that ground locally produced boxed beef for hamburgers on site. Case finding was conducted through public messaging, employee surveys, and disease surveillance. All potential cases were interviewed using a standard questionnaire. A confirmed case was defined as laboratory-confirmed E. coli O157:H7 with exposure to restaurant A. A probable case was defined as a patient with compatible symptoms and exposure to restaurant A but without laboratory confirmation. All human and food isolates were characterized by pulsed-field gel electrophoresis and multilocus variable-number tandem repeat analysis. The analysis identified 14 confirmed and 10 probable cases of E. coli; 18 nonintact ground beef samples tested positive for E. coli O157:H7. Nine confirmed cases were restaurant A employees. All confirmed cases recalled eating a restaurant A hamburger in the 10 days before illness onset; most cases reported consuming medium to rare hamburgers. Multiple pulsed-field gel electrophoresis and multilocus variable-number tandem repeat analysis patterns were identified among both the human and ground beef isolates, and the patient isolates matched those found in ground beef samples. Restaurant A voluntarily closed for 1.5 days, changed beef suppliers, ceased grinding beef in-house, and has had no new cases since reopening.

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