scholarly journals Prevalence and Characterization of Non-O157 Shiga Toxin-ProducingEscherichia coliIsolates from Commercial Ground Beef in the United States

2011 ◽  
Vol 77 (6) ◽  
pp. 2103-2112 ◽  
Author(s):  
Joseph M. Bosilevac ◽  
Mohammad Koohmaraie
Keyword(s):  
United States ◽  
Virulence Factors ◽  
Shiga Toxin ◽  
Iron Acquisition ◽  
Ground Beef ◽  
Dna Amplification ◽  
The United States ◽  
Virulence Plasmid ◽  
Beef Industry

ABSTRACTEscherichia coliO157:H7 is a Shiga toxin (stx)-producingE. coli(STEC) strain that has been classified as an adulterant in U.S. beef. However, numerous other non-O157 STEC strains are associated with diseases of various severities and have become an increasing concern to the beef industry, regulatory officials, and the public. This study reports on the prevalence and characterization of non-O157 STEC in commercial ground beef samples (n= 4,133) obtained from numerous manufacturers across the United States over a period of 24 months. All samples were screened by DNA amplification for the presence of Shiga toxin genes, which were present in 1,006 (24.3%) of the samples. Then, culture isolation of an STEC isolate from all samples that containedstx1and/orstx2was attempted. Of the 1,006 positive ground beef samples screened forstx, 300 (7.3% of the total of 4,133) were confirmed to have at least one strain of STEC present by culture isolation. In total, 338 unique STEC isolates were recovered from the 300 samples that yielded an STEC isolate. All unique STEC isolates were serotyped and were characterized for the presence of known virulence factors. These included Shiga toxin subtypes, intimin subtypes, and accessory virulence factors related to adherence (saa,iha,lifA), toxicity (cnf,subA,astA), iron acquisition (chuA), and the presence of the large 60-MDa virulence plasmid (espP,etpD,toxB,katP,toxB). The isolates were also characterized by use of a pathogenicity molecular risk assessment (MRA; based on the presence of various O-islandnlegenes). Results of this characterization identified 10 STEC isolates (0.24% of the 4,133 total) that may be considered a significant food safety threat, defined by the presence ofeae,subA, andnlegenes.

scholarly journals Ground Beef: Implications for the Southeastern U.S. Beef Industry

1979 ◽  
Vol 11 (2) ◽  
pp. 21-26
Author(s):  
J. Richard Conner ◽  
Robert W. Rogers
Keyword(s):  
United States ◽  
Fast Food ◽  
Ground Beef ◽  
The United States ◽  
Beef Industry ◽  
Increasing Trend ◽  
Fast Food Restaurants ◽  
Eating Out ◽  
At Home

Currently the United States consumes an estimated 39 to 45 percent of its beef in the “ground” form [3, 7, 8]. As recently as 1972 the estimated percentage of beef consumed as ground was only 33 [3] and some industry leaders have estimated the proportion by 1985 to be from 50 to 65 percent [5, 8, 11, 12]. This increasing trend in the percentage of beef consumed in the ground form is often attributed to several factors including (1) an increase in the percentage of wives working away from home which results in more “eating out” and less home preparation of “traditional” meat dishes for those meals consumed at home, and (2) the continuing growth of the fast-food restaurants and their popular “hamburger” meals [5, 8, 11, 12].

scholarly journals Virulence Profiling of Shiga Toxin-Producing Escherichia coli O111:NM Isolates from Cattle

2013 ◽  
Vol 79 (13) ◽  
pp. 4164-4165 ◽  
Author(s):  
Musafiri Karama ◽  
Carlton L. Gyles
Keyword(s):  
United States ◽  
Escherichia Coli ◽  
Virulence Factors ◽  
Shiga Toxin ◽  
Disease Outbreaks ◽  
The United States ◽  
Full Spectrum ◽  
Gene Markers ◽  
Content Type

ABSTRACTShiga toxin-producingEscherichia coli(STEC) O111:NM is an important serotype that has been incriminated in disease outbreaks in the United States. This study characterized cattle STEC O111:NM for virulence factors and markers by PCR. Major conclusions are that STEC O111:NM characterized in this study lacksstx2and the full spectrum ofnlegene markers, and it has an incomplete OI-122.

scholarly journals Microbiological Characterization of Imported and Domestic Boneless Beef Trim Used for Ground Beef†

2007 ◽  
Vol 70 (2) ◽  
pp. 440-449 ◽  
Author(s):  
JOSEPH M. BOSILEVAC ◽  
MICHAEL N. GUERINI ◽  
DAYNA M. BRICHTA-HARHAY ◽  
TERRANCE M. ARTHUR ◽  
MOHAMMAD KOOHMARAIE
Keyword(s):  
United States ◽  
Microbiological Quality ◽  
Ground Beef ◽  
The United States ◽  
E Coli ◽  
Uremic Syndrome ◽  
Etiological Agents ◽  
Campylobacter Spp

The United States imports lean boneless beef trim from Australia (AUS), New Zealand (NZL), and Uruguay (URY) to meet demand for ground beef production. The reported incidence of and etiological agents responsible for foodborne diseases differ between these countries and the United States. Our objective was to determine whether current U.S. microbiological profiling adequately addresses the potential differences between foreign and domestic beef trim. We compared the hygienic status of imported and domestic (USA) beef trim by enumeration of aerobic bacteria, Enterobacteriaceae, coliforms, Escherichia coli, and Staphylococcus aureus. We also compared the prevalence of pathogens between imported and domestic samples by screening for the presence of Salmonella, Campylobacter spp., Listeria spp., and non-O157 Shiga toxin–producing E. coli (STEC). A total of 1,186 samples (487 USA, 220 AUS, 223 NZL, and 256 URY) of boneless beef trim were analyzed. Results of enumeration revealed significant differences between samples from all countries, with the lowest pathogen numbers in samples from AUS and the highest in samples from URY. Six Salmonella isolates (1 NZL, 1 URY, and 4 USA), 79 L. monocytogenes isolates (4 AUS, 5 NZL, 53 URY, and 17 USA), and 7 Campylobacter isolates (1 NZL, 1 URY, 5 USA) were found among the trim samples tested. Non-O157 STEC prevalence was 10% in NZL samples and about 30% in all of the other samples; 99 STEC strains were isolated. Serotyping of these isolates revealed that serotypes associated with hemolytic uremic syndrome were not different in prevalence between imported and domestic beef trim. Although it may be tempting to do so, these data cannot be used to compare the microbiological quality of beef trim between the countries examined. However, these results indicate that the current pathogen monitoring procedures in the United States are adequate for evaluation of imported beef trim.

scholarly journals Characterization of a Campylobacter jejuni VirK Protein Homolog as a Novel Virulence Determinant

2009 ◽  
Vol 77 (12) ◽  
pp. 5428-5436 ◽  
Author(s):  
Veronica Novik ◽  
Dirk Hofreuter ◽  
Jorge E. Galán
Keyword(s):  
United States ◽  
Campylobacter Jejuni ◽  
Virulence Factors ◽  
Unique Feature ◽  
The United States ◽  
Genetic Screen ◽  
Food Borne ◽  
Food Borne Illness ◽  
Antimicrobial Peptide Resistance

ABSTRACT Campylobacter jejuni is a leading cause of food-borne illness in the United States. Despite significant recent advances, its mechanisms of pathogenesis are poorly understood. A unique feature of this pathogen is that, with some exceptions, it lacks homologs of known virulence factors from other pathogens. Through a genetic screen, we have identified a C. jejuni homolog of the VirK family of virulence factors, which is essential for antimicrobial peptide resistance and mouse virulence.

Establishment of non-O157 Shiga Toxin-Producing Escherichia coli (STEC) baseline of retail ground beef in the United States

Meat Science ◽  
2014 ◽  
Vol 96 (1) ◽  
pp. 484
Author(s):  
Y.T. Liao⁎ ◽  
G.H. Loneragan ◽  
J.C. Brooks ◽  
A. Echeverry ◽  
M.F. Miller ◽  
...  
Keyword(s):  
United States ◽  
Escherichia Coli ◽  
Shiga Toxin ◽  
Ground Beef ◽  
The United States

Characterization and Virulence Potential of Serogroup O113 Shiga Toxin–Producing Escherichia coli Strains Isolated from Beef and Cattle in the United States

2017 ◽  
Vol 80 (3) ◽  
pp. 383-391 ◽  
Author(s):  
Peter Feng ◽  
Sabine Delannoy ◽  
David W. Lacher ◽  
Joseph M. Bosilevac ◽  
Patrick Fach
Keyword(s):  
United States ◽  
Escherichia Coli ◽  
Shiga Toxin ◽  
Severe Disease ◽  
Ground Beef ◽  
The United States ◽  
Intestinal Epithelial ◽  
Virulence Potential ◽  
Beef Products ◽  
Genetic Profiles

ABSTRACT Shiga toxin–producing Escherichia coli (STEC) of serotype O113:H21 have caused severe diseases but are unusual in that they do not produce the intimin protein required for adherence to intestinal epithelial cells. Strains of serogroup O113 are one of the most common STEC found in ground beef and beef products in the United States, but their virulence potential is unknown. We used a microarray to characterize 65 O113 strains isolated in the United States from ground beef, beef trim, cattle feces, and fresh spinach. Most were O113:H21 strains, but there were also nine strains of O113:H4 serotype. Although strains within the same serotype had similar profiles for the genes that were tested on the array, the profiles were distinct between the two serotypes, and the strains belonged to different clonal groups. Analysis by clustered regularly interspaced short palindromic repeat analysis showed that O113:H4 strains are conserved genetically, but the O113:H21 strains showed considerable polymorphism and genetic diversity. In comparison to the O113:H21 strains from Australia that were implicated in severe disease, the U.S. isolates showed similar genetic profiles to the known pathogens from Australia, suggesting that these may also have the potential to cause infections.

Non-O157 Shiga Toxin–Producing Escherichia coli in U.S. Retail Ground Beef

2014 ◽  
Vol 77 (7) ◽  
pp. 1188-1192 ◽  
Author(s):  
YEN-TE LIAO ◽  
MARKUS F. MILLER ◽  
GUY H. LONERAGAN ◽  
J. CHANCE BROOKS ◽  
ALEJANDRO ECHEVERRY ◽  
...  
Keyword(s):  
United States ◽  
Escherichia Coli ◽  
Shiga Toxin ◽  
Ground Beef ◽  
The United States ◽  
Latex Agglutination ◽  
Retail Stores ◽  
Convenience Sample ◽  
Two Samples ◽  
Beef Products

Shiga toxin–producing Escherichia coli (STEC) serotype O157:H7 and serogroups O26, O45, O103, O111, O121, and O145 are the leading cause of STEC-associated infections in humans in the United States. In the United States, these organisms are considered adulterants in raw nonintact beef products and in intact beef destined to be made into or used in nonintact raw beef products. The objective of this study was to provide an estimate of the burden of the six serogroups of non-O157 STEC in ground beef obtained from retail stores across the United States. A convenience sample of commercial ground beef products (n = 1,129) were purchased from retail stores in 24 states from October 2011 to May 2012. The samples had various lean/fat proportions, muscle group of origin (chuck, round, sirloin, or not specified), and packaging types. For each ground beef sample, 25 g was inoculated in 225 ml of modified tryptic soy broth, stomached for 1 min, and then incubated at 41°C for 18 ± 2 h. These enrichment cultures were then screened for stx, eae, and O group genes using a commercially available, closed-platform PCR-based method. The potential positive samples were subjected to immunomagnetic separation and plated on modified Rainbow agar. Morphologically typical colonies were subjected to latex agglutination and PCR determination of stx and eae genes. Nine (0.8%) of the ground beef samples were potentially positive for at least one STEC serogroup after PCR screening. The serogroups detected by PCR assay were O26 (four samples), O103 (four samples), O145 (three samples), O45 (two samples), and O121 (one sample). No STEC isolates belonging to these serogroups were recovered from the sample cultures. The current research provides updated surveillance data for non-O157 STEC isolates among commercial ground beef products and information regarding the potential sources of contamination from different parts of beef trims destined for ground beef production.

scholarly journals Prevalence and Characterization of Salmonellae in Commercial Ground Beef in the United States

2009 ◽  
Vol 75 (7) ◽  
pp. 1892-1900 ◽  
Author(s):  
Joseph M. Bosilevac ◽  
Michael N. Guerini ◽  
Norasak Kalchayanand ◽  
Mohammad Koohmaraie
Keyword(s):  
United States ◽  
Salmonella Enterica ◽  
Regional Differences ◽  
Ground Beef ◽  
The United States ◽  
Multidrug Resistant ◽  
Antibiotic Susceptibilities ◽  
Total Prevalence ◽  
Common Serotypes

ABSTRACT Commercially produced ground beef samples (n = 4,136) were collected from seven regions of the United States over a 24-month period (July 2005 to June 2007) and analyzed for the presence of Salmonella enterica by using methods that concurrently provided total prevalence and enumerable levels. The overall prevalence of Salmonella strains was 4.2%. Enumeration showed that 94.2% were present at levels below 2 CFU/g. Regional monthly prevalences of Salmonella strains varied from 1.8% to 6.5% but were not statistically different (P > 0.05). All Salmonella isolates were serotyped and their antibiotic susceptibilities determined and analyzed by pulsed-field gel electrophoresis (PFGE). The most common serotypes identified were Salmonella enterica serotypes Montevideo, Anatum, Muenster, and Mbandaka, with these accounting for one-half of the isolates obtained. The prevalence of multidrug-resistant (MDR) Salmonella was determined to be 0.6%. The most common MDR serotypes were Salmonella enterica serotypes Dublin, Reading, and Typhimurium. MDR strains had resistance to between 2 and 10 antibiotics. There were no regional differences in prevalence of MDR Salmonella. PFGE analysis revealed that indistinguishable XbaI and AvrII restriction digest patterns (RDPs) could be observed in isolates of the same serotype found in different regions and months of sampling. The RDPs of 19 Salmonella strains were compared to RDPs in the PulseNet USA database. Thirteen were indistinguishable from existing patterns, and the number of records for each ranged from 1 to 478. These data show that Salmonella prevalence in commercial ground beef is low and suggest that attempts to identify sources contributing to Salmonella in ground beef by serotype, antibiogram, and PFGE cannot be made without additional documented evidence.

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