1
|
Ray R, Singh P. Prevalence and Implications of Shiga Toxin-Producing E. coli in Farm and Wild Ruminants. Pathogens 2022; 11:1332. [PMID: 36422584 PMCID: PMC9694250 DOI: 10.3390/pathogens11111332] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 11/04/2022] [Accepted: 11/08/2022] [Indexed: 08/27/2023] Open
Abstract
Shiga-toxin-producing Escherichia coli (STEC) is a food-borne pathogen that causes human gastrointestinal infections across the globe, leading to kidney failure or even death in severe cases. E. coli are commensal members of humans and animals' (cattle, bison, and pigs) guts, however, may acquire Shiga-toxin-encoded phages. This acquisition or colonization by STEC may lead to dysbiosis in the intestinal microbial community of the host. Wildlife and livestock animals can be asymptomatically colonized by STEC, leading to pathogen shedding and transmission. Furthermore, there has been a steady uptick in new STEC variants representing various serotypes. These, along with hybrids of other pathogenic E. coli (UPEC and ExPEC), are of serious concern, especially when they possess enhanced antimicrobial resistance, biofilm formation, etc. Recent studies have reported these in the livestock and food industry with minimal focus on wildlife. Disturbed natural habitats and changing climates are increasingly creating wildlife reservoirs of these pathogens, leading to a rise in zoonotic infections. Therefore, this review comprehensively surveyed studies on STEC prevalence in livestock and wildlife hosts. We further present important microbial and environmental factors contributing to STEC spread as well as infections. Finally, we delve into potential strategies for limiting STEC shedding and transmission.
Collapse
Affiliation(s)
| | - Pallavi Singh
- Department of Biological Sciences, Northern Illinois University, Dekalb, IL 60115, USA
| |
Collapse
|
2
|
Mohammadi Shad Z, Venkitasamy C, Wen Z. Corn distillers dried grains with solubles: Production, properties, and potential uses. Cereal Chem 2021. [DOI: 10.1002/cche.10445] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
| | | | - Zhiyou Wen
- Food Science and Human Nutrition Department Iowa State University Ames IA USA
| |
Collapse
|
3
|
Dewsbury DMA, Cernicchiaro N, Depenbusch B, Nagaraja TG, Renter DG. Effectiveness of a Direct-Fed Microbial Product Containing Lactobacillus acidophilus and Lactobacillus casei in Reducing Fecal Shedding of Escherichia coli O157:H7 in Commercial Feedlot Cattle. Foodborne Pathog Dis 2020; 18:16-23. [PMID: 32898446 DOI: 10.1089/fpd.2020.2828] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The objective of this study was to evaluate the effectiveness of a direct-fed microbial (DFM) product in reducing fecal shedding of Escherichia coli O157:H7 in finishing commercial feedlot cattle in Kansas (KS) and Nebraska (NE). Utilizing a randomized complete block design within the feedlot (KS, n = 1; NE, n = 1), cattle were randomly allocated to 20 pens, grouped in blocks of two based on allocation date, and then, within the block, randomly assigned to a treatment group (DFM or negative control). The DFM product was included in the diet at a targeted daily dose of 1 × 109 colony-forming units (CFU) of the Lactobacillus acidophilus and Lactobacillus casei combination per animal for at least 60 d before sampling. Feedlots were sampled for four consecutive weeks; weekly sampling consisted of collecting 20 pen floor fecal samples per pen. Fecal samples were subjected to culture-based methods for detection and isolation of E. coli O157, and positive samples were quantified using real-time polymerase chain reaction. Primary outcomes of interest were fecal prevalence of E. coli O157:H7 and E. coli O157 supershedding (≥104 CFU/g of feces) prevalence. Data for each feedlot were analyzed at the pen level using mixed models accounting for the study design features. Model-adjusted mean E. coli O157:H7 fecal prevalence estimates (standard error of the mean [SEM]) for DFM and control groups were 8.2% (SEM = 2.2%) and 9.9% (SEM = 2.5%) in KS and 14.6% (SEM = 2.8%) versus 14.3% (SEM = 2.6%) in NE; prevalence did not differ significantly between treatment groups at either site (KS, p = 0.51; NE, p = 0.92). Mean E. coli O157 supershedding prevalence estimates for DFM and control groups were 2.2% (SEM = 0.7%) versus 1.8% (SEM = 0.7%) in KS (p = 0.66) and 6.7% (SEM = 1.5%) versus 3.2% (SEM = 1.0%) in NE (p = 0.04). In conclusion, administering the DFM product in the finishing diet of feedlot cattle did not significantly reduce E. coli O157:H7 fecal prevalence or supershedding prevalence in study pens at either commercial feedlot.
Collapse
Affiliation(s)
- Diana M A Dewsbury
- Center for Outcomes Research and Epidemiology, Kansas State University, Manhattan, Kansas, USA.,Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA
| | - Natalia Cernicchiaro
- Center for Outcomes Research and Epidemiology, Kansas State University, Manhattan, Kansas, USA.,Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA
| | | | - T G Nagaraja
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA
| | - David G Renter
- Center for Outcomes Research and Epidemiology, Kansas State University, Manhattan, Kansas, USA.,Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA
| |
Collapse
|
4
|
|
5
|
Sustainability of feeding plant by-products: A review of the implications for ruminant meat production. Anim Feed Sci Technol 2019. [DOI: 10.1016/j.anifeedsci.2019.02.006] [Citation(s) in RCA: 111] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
6
|
Mir RA, Kudva IT. Antibiotic‐resistant Shiga toxin‐producing
Escherichia coli
: An overview of prevalence and intervention strategies. Zoonoses Public Health 2018; 66:1-13. [DOI: 10.1111/zph.12533] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 10/08/2018] [Indexed: 12/22/2022]
Affiliation(s)
- Raies A. Mir
- Food Safety and Enteric Pathogens Research Unit, National Animal Disease Center, Agricultural Research Service U.S. Department of Agriculture Ames Iowa
- Oak Ridge Institute for Science and Education (ORISE) ARS Research Participation Program Oak Ridge Tennessee
| | - Indira T. Kudva
- Food Safety and Enteric Pathogens Research Unit, National Animal Disease Center, Agricultural Research Service U.S. Department of Agriculture Ames Iowa
| |
Collapse
|
7
|
Chaney WE, Maloney R, Johnson BJ, Brooks JC, Brashears MM, Loneragan GH. Corn-Based Distillers' Grains in Diets for Feedlot Cattle Are Associated with the Burden of Escherichia coli O157 in Feces. Foodborne Pathog Dis 2018; 15:398-405. [PMID: 29620957 DOI: 10.1089/fpd.2017.2395] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Inclusion of distillers' grains (DGs) has been associated with increased prevalence of Escherichia coli O157:H7 in cattle housed in research settings. Our objective was to quantify the relationship between inclusion of DGs in commercial feedlot rations and the burden of E. coli O157. A convenience sample of 10 feedlots was enrolled based on DG use in finishing diets; 1 cohort included 5 feedlots in which DGs were greater than 15% of the dietary dry matter and the other cohort consisted of 5 feedlots at a concentration less than 8%. Sampling occurred at each feedlot on four occasions at ∼6-week intervals. At each feedlot visit, 4 pens of cattle within 3 weeks of slaughter were selected and 24 freshly voided fecal pats were sampled. Ten-gram samples were enriched in 90 mL of modified tryptic soy broth with novobiocin (20 mg/L) for 14 h at 42°C. Enrichments were subjected to immunomagnetic separation, plating onto chromogenic agar with novobiocin (5 mg/L) and potassium tellurite (2.5 mg/L), incubation for 18 h at 37°C, and latex agglutination of morphologically typical colonies. E. coli O157 was recovered from 16.7% of 3840 samples. Adjusted prevalence was 14.3% after controlling for within-feedlot and within-pen clustering. Prevalence during each sampling period was 19.9% (round 1), 21.0% (round 2), 14.1% (round 3), and 11.7% (round 4). Prevalence varied between cohorts, but this difference varied over time (p = 0.06). Among those with greater than 15% of the diet as DGs, prevalence was greater than those with less than 8% inclusion for all rounds of sampling (p < 0.01). Averaged across time, prevalence was 23.9% and 9.4% for those with greater than 15% and those with less than 8% of DGs, respectively. While observational, these data provide real-world support of reports of increased E. coli O157:H7 burden associated with DG use in cattle diets.
Collapse
Affiliation(s)
- W Evan Chaney
- Department of Animal and Food Sciences, International Center for Food Industry Excellence, Texas Tech University , Lubbock, Texas
| | - Rebecca Maloney
- Department of Animal and Food Sciences, International Center for Food Industry Excellence, Texas Tech University , Lubbock, Texas
| | - Bradley J Johnson
- Department of Animal and Food Sciences, International Center for Food Industry Excellence, Texas Tech University , Lubbock, Texas
| | - J Chance Brooks
- Department of Animal and Food Sciences, International Center for Food Industry Excellence, Texas Tech University , Lubbock, Texas
| | - Mindy M Brashears
- Department of Animal and Food Sciences, International Center for Food Industry Excellence, Texas Tech University , Lubbock, Texas
| | - Guy H Loneragan
- Department of Animal and Food Sciences, International Center for Food Industry Excellence, Texas Tech University , Lubbock, Texas
| |
Collapse
|
8
|
Lawan A, Jesse FFA, Idris UH, Odhah MN, Arsalan M, Muhammad NA, Bhutto KR, Peter ID, Abraham GA, Wahid AH, Mohd-Azmi ML, Zamri-Saad M. Mucosal and systemic responses of immunogenic vaccines candidates against enteric Escherichia coli infections in ruminants: A review. Microb Pathog 2018; 117:175-183. [PMID: 29471137 DOI: 10.1016/j.micpath.2018.02.039] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 02/17/2018] [Accepted: 02/18/2018] [Indexed: 02/06/2023]
Abstract
Innumerable Escherichia coli of animal origin are identified, which are of economic significance, likewise, cattle, sheep and goats are the carrier of enterohaemorrhagic E. coli, which are less pathogenic, and can spread to people by way of direct contact and through the contamination of foodstuff or portable drinking water, causing serious illness. The immunization of ruminants has been carried out for ages and is largely acknowledged as the most economical and maintainable process of monitoring E. coli infection in ruminants. Yet, only a limited number of E. coli vaccines are obtainable. Mucosal surfaces are the most important ingress for E. coli and thus mucosal immune responses function as the primary means of fortification. Largely contemporary vaccination processes are done by parenteral administration and merely limited number of E. coli vaccines are inoculated via mucosal itinerary, due to its decreased efficacy. Nevertheless, aiming at maximal mucosal partitions to stimulate defensive immunity at both mucosal compartments and systemic site epitomises a prodigious task. Enormous determinations are involved in order to improve on novel mucosal E. coli vaccines candidate by choosing apposite antigens with potent immunogenicity, manipulating novel mucosal itineraries of inoculation and choosing immune-inducing adjuvants. The target of E. coli mucosal vaccines is to stimulate a comprehensive, effective and defensive immunity by specifically counteracting the antibodies at mucosal linings and by the stimulation of cellular immunity. Furthermore, effective E. coli mucosal vaccine would make vaccination measures stress-free and appropriate for large number of inoculation. On account of contemporary advancement in proteomics, metagenomics, metabolomics and transcriptomics research, a comprehensive appraisal of the immeasurable genes and proteins that were divulged by a bacterium is now in easy reach. Moreover, there exist marvellous prospects in this bourgeoning technologies in comprehending the host bacteria affiliation. Accordingly, the flourishing knowledge could massively guarantee to the progression of immunogenic vaccines against E. coli infections in both humans and animals. This review highlight and expounds on the current prominence of mucosal and systemic immunogenic vaccines for the prevention of E. coli infections in ruminants.
Collapse
Affiliation(s)
- A Lawan
- Department of Veterinary Clinical Studies, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia; Department of Veterinary Medicine, Faculty of Veterinary Medicine, University of Maiduguri, Nigeria.
| | - F F A Jesse
- Department of Veterinary Clinical Studies, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia; Department of Farm & Exotic Animals Medicine & Surgery, Faculty of Veterinary Medicine, Universiti Putra Malaysia (UPM), 43400 UPM, Serdang, Selangor, Malaysia
| | - U H Idris
- Department of Veterinary Clinical Studies, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia; Department of Veterinary Public Health and Preventive Medicine, Faculty of Veterinary Medicine, University of Maiduguri, Nigeria
| | - M N Odhah
- Department of Veterinary Clinical Studies, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia; Department of Veterinary Medicine, Faculty of Agriculture and Veterinary Medicine, Thamar University, Yemen
| | - M Arsalan
- Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, Malaysia; Livestock and Dairy Development Department Baluchistan, Pakistan
| | - N A Muhammad
- Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, Malaysia
| | - K R Bhutto
- Department of Veterinary Clinical Studies, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia; Veterinary Research & Diagnosis, Livestock and Fisheries Department, Sindh, Pakistan
| | - I D Peter
- Department of Veterinary Clinical Studies, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia; Department of Theriogenology, Faculty of Veterinary Medicine, University of Maiduguri, Nigeria
| | - G A Abraham
- Department of Veterinary Clinical Studies, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia; Department of Farm & Exotic Animals Medicine & Surgery, Faculty of Veterinary Medicine, Universiti Putra Malaysia (UPM), 43400 UPM, Serdang, Selangor, Malaysia
| | - A H Wahid
- Department of Veterinary Clinical Studies, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia
| | - M L Mohd-Azmi
- Department of Veterinary Pathology and Microbiology, Faculty of Veterinary Medicine, Universiti Putra Malaysia, Malaysia
| | - M Zamri-Saad
- Department of Veterinary Pathology and Microbiology, Faculty of Veterinary Medicine, Universiti Putra Malaysia, Malaysia
| |
Collapse
|
9
|
Berry ED, Wells JE, Varel VH, Hales KE, Kalchayanand N. Persistence of Escherichia coli O157:H7 and Total Escherichia coli in Feces and Feedlot Surface Manure from Cattle Fed Diets with and without Corn or Sorghum Wet Distillers Grains with Solubles. J Food Prot 2017; 80:1317-1327. [PMID: 28708031 DOI: 10.4315/0362-028x.jfp-17-018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Feeding corn wet distillers grains with solubles (WDGS) to cattle can increase the load of Escherichia coli O157:H7 in feces and on hides, but the mechanisms are not fully understood. The objective of these experiments was to examine a role for the persistence of E. coli O157:H7 in the feces and feedlot pen surfaces of cattle fed WDGS. In the first study, feces from steers fed 0, 20, 40, or 60% corn WDGS were inoculated with E. coli O157:H7. The E. coli O157:H7 numbers in feces from cattle fed 0% corn WDGS rapidly decreased (P < 0.05), from 6.28 to 2.48 log CFU/g of feces by day 14. In contrast, the E. coli O157:H7 numbers in feces from cattle fed 20, 40, and 60% corn WDGS were 4.21, 5.59, and 6.13 log CFU/g of feces, respectively, on day 14. A second study evaluated the survival of E. coli O157:H7 in feces from cattle fed 0 and 40% corn WDGS. Feces were collected before and 28 days after the dietary corn was switched from high-moisture corn to dry-rolled corn. Within dietary corn source, the pathogen persisted at higher concentrations (P < 0.05) in 40% corn WDGS feces at day 7 than in 0% WDGS. For 40% corn WDGS feces, E. coli O157:H7 persisted at higher concentrations (P < 0.05) at day 7 in feces from cattle fed high-moisture corn (5.36 log CFU/g) than from those fed dry-rolled corn (4.27 log CFU/g). The percentage of WDGS had no effect on the E. coli O157:H7 counts in feces from cattle fed steam-flaked corn-based diets containing 0, 15, and 30% sorghum WDGS. Greater persistence of E. coli O157:H7 on the pen surfaces of animals fed corn WDGS was not demonstrated, although these pens had a higher prevalence of the pathogen in the feedlot surface manure after the cattle were removed. Both or either the greater persistence and higher numbers of E. coli O157:H7 in the environment of cattle fed WDGS may play a part in the increased prevalence of E. coli O157:H7 in cattle by increasing the transmission risk.
Collapse
Affiliation(s)
- Elaine D Berry
- U.S. Department of Agriculture, Agricultural Research Service, Roman L. Hruska U.S. Meat Animal Research Center, P.O. Box 166, Spur 18D, Clay Center, Nebraska 68933-0166, USA
| | - James E Wells
- U.S. Department of Agriculture, Agricultural Research Service, Roman L. Hruska U.S. Meat Animal Research Center, P.O. Box 166, Spur 18D, Clay Center, Nebraska 68933-0166, USA
| | - Vincent H Varel
- U.S. Department of Agriculture, Agricultural Research Service, Roman L. Hruska U.S. Meat Animal Research Center, P.O. Box 166, Spur 18D, Clay Center, Nebraska 68933-0166, USA
| | - Kristin E Hales
- U.S. Department of Agriculture, Agricultural Research Service, Roman L. Hruska U.S. Meat Animal Research Center, P.O. Box 166, Spur 18D, Clay Center, Nebraska 68933-0166, USA
| | - Norasak Kalchayanand
- U.S. Department of Agriculture, Agricultural Research Service, Roman L. Hruska U.S. Meat Animal Research Center, P.O. Box 166, Spur 18D, Clay Center, Nebraska 68933-0166, USA
| |
Collapse
|
10
|
Schneider LG, Klopfenstein TJ, Stromberg ZR, Lewis GL, Erickson GE, Moxley RA, Smith DR. A randomized controlled trial to evaluate the effects of dietary fibre from distillers grains on enterohemorrhagic Escherichia coli detection from the rectoanal mucosa and hides of feedlot steers. Zoonoses Public Health 2017; 65:124-133. [PMID: 28755469 DOI: 10.1111/zph.12379] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Indexed: 11/26/2022]
Abstract
Feeding high levels (≥40% dry matter) of distillers grains may increase the risk for cattle to carry enterohemorrhagic Escherichia coli (EHEC) O157. The mechanism for the increased risk is not known nor whether non-O157 EHEC are similarly affected. Our objective was to test whether the fibre content or other components of modified distillers grains plus solubles (MDGS) affects the probability for cattle to carry EHEC serogroups of public health importance. A 2 × 2 plus 1 factorial treatment arrangement within a randomized block design was utilized. Within each of four blocks, 25 feedlot pens (n = 8 steers/pen) were assigned randomly to (i) corn-based control diet; (ii) 20% dry matter (DM) MDGS; (iii) 40% DM MDGS; (iv) corn bran added to corn-based diet to match fibre of 20% MDGS or (v) 40% MDGS. Rectoanal mucosa swabs (RAMS) were collected on day (d)0, d35, d70 and d105; hide swabs were collected on the last feeding day. Samples were tested for EHEC by a molecular screening assay. The effects of fibre source and fibre level on EHEC carriage were tested using multilevel logistic regression (generalized linear mixed models; α = 0.05). EHEC O45 RAMS detection was associated with fibre level, source and sampling day. EHEC O103 RAMS detection increased by feeding 40% MDGS but not the corresponding corn bran diet. Hide contamination by EHEC O45 or O103 was less likely in cattle fed MDGS compared to corn bran diets. EHEC O111 RAMS detection decreased by feeding 40% MDGS but not by feeding the corresponding corn bran diet. Detection of EHEC O157 or O145 was not associated with dietary factors. Feeding 40% MDGS increased the probability for carriage of some EHEC serogroups but decreased probability of others, which indicated that EHEC serogroups have different risk factors associated with feeding MDGS and little association with dietary fibre.
Collapse
Affiliation(s)
- L G Schneider
- College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, USA
| | - T J Klopfenstein
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Z R Stromberg
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - G L Lewis
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - G E Erickson
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - R A Moxley
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - D R Smith
- College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, USA
| |
Collapse
|
11
|
Abstract
Foods of animal origin, including beef and dairy products, are nutritious and important to global food security. However, there are important risks to human health from hazards that are introduced to beef and dairy products on the farm. Food safety hazards may be chemical, biological, or physical in nature. Considerations about protecting the safety of beef and dairy products must begin prior to harvest because some potential food safety hazards introduced at the farm (e.g., chemical residues) cannot be mitigated by subsequent postharvest food processing steps. Also, some people have preferences for consuming food that has not been through postharvest processing even though those foods may be unsafe because of microbiological hazards originating from the farm. Because of human fallibility and complex microbial ecologies, many of the preharvest hazards associated with beef and dairy products cannot entirely be eliminated, but the risk for most can be reduced through systematic interventions taken on the farm. Beef and dairy farms differ widely in production practices because of differences in natural, human, and capital resources. Therefore, the actions necessary to minimize on-farm food safety hazards must be farm-specific and they must address scientific, political, economic, and practical aspects. Notable successes in controlling and preventing on-farm hazards to food safety have occurred through a combination of voluntary and regulatory efforts.
Collapse
|
12
|
Stein RA, Katz DE. Escherichia coli, cattle and the propagation of disease. FEMS Microbiol Lett 2017; 364:3059138. [PMID: 28333229 PMCID: PMC7108533 DOI: 10.1093/femsle/fnx050] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 02/28/2017] [Indexed: 12/21/2022] Open
Abstract
Several early models describing host–pathogen interaction have assumed that each individual host has approximately the same likelihood of becoming infected or of infecting others. More recently, a concept that has been increasingly emphasized in many studies is that for many infectious diseases, transmission is not homogeneous but highly skewed at the level of populations. In what became known as the ‘20/80 rule’, about 20% of the hosts in a population were found to contribute to about 80% of the transmission potential. These heterogeneities have been described for the interaction between many microorganisms and their human or animal hosts. Several epidemiological studies have reported transmission heterogeneities for Escherichia coli by cattle, a phenomenon with far-reaching agricultural, medical and public health implications. Focusing on E. coli as a case study, this paper will describe super-spreading and super-shedding by cattle, review the main factors that shape these transmission heterogeneities and examine the interface with human health. Escherichia coli super-shedding and super-spreading by cattle are shaped by microorganism-specific, cattle-specific and environmental factors. Understanding the factors that shape heterogeneities in E. coli dispersion by cattle and the implications for human health represent key components that are critical for targeted infection control initiatives.
Collapse
Affiliation(s)
- Richard A Stein
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA.,Department of Natural Sciences, LaGuardia Community College, City University of New York, Long Island City, NY 11101, USA
| | - David E Katz
- Department of Internal Medicine, Shaare Zedek Medical Center, Hebrew University School of Medicine, Jerusalem 91031, Israel
| |
Collapse
|
13
|
Keomanivong FE, Ruch MC, Liu JH, Kirsch JD, Bauer ML, Dahlen CR, Kapphahn M, Borhan MS, Rahman S, Swanson KC. Influence of dry-rolled corn processing and distiller’s grain inclusion rate on ruminal pH, ammonia and volatile fatty acid concentration, in vitro methane production and enzyme activity. Anim Feed Sci Technol 2017. [DOI: 10.1016/j.anifeedsci.2017.04.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
14
|
Fink RC, Popowski JM, Anderson JE, Tran JL, Kalyanikutty S, Crawford GI, DiCostanzo A, Cox RB, Diez-Gonzalez F. Impact of distillers grain solids (DGS) and seasonality on the prevalence of Escherichia coli O157 at an abattoir in the U. S. Upper Midwest. JOURNAL OF APPLIED ANIMAL RESEARCH 2017. [DOI: 10.1080/09712119.2017.1288628] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Ryan C. Fink
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN, USA
| | - Jackie M. Popowski
- Department of Animal Science, University of Minnesota, St. Paul, MN, USA
| | - Jon E. Anderson
- Division of Mathematics and Science, University of Minnesota, Morris, MN, USA
| | - Johanna L. Tran
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN, USA
| | - Sudha Kalyanikutty
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN, USA
| | - Grant I. Crawford
- Department of Animal Science, University of Minnesota, St. Paul, MN, USA
| | - Alfredo DiCostanzo
- Department of Animal Science, University of Minnesota, St. Paul, MN, USA
| | - Ryan B. Cox
- Department of Animal Science, University of Minnesota, St. Paul, MN, USA
| | | |
Collapse
|
15
|
Abstract
This introductory article provides an overview of preharvest food safety activities and initiatives for the past 15 years. The section on traditional areas of preharvest food safety focuses on significant scientific advancements that are a culmination of collaborative efforts (both public health and agriculture) and significant research results. The highlighted advancements provide the foundation for exploring future preharvest areas and for improving and focusing on more specific intervention/control/prevention strategies. Examples include Escherichia coli and cattle, Salmonella and Campylobacter in poultry, and interventions and prevention and control programs. The section on "nontraditional" preharvest food safety areas brings attention to potential emerging food safety issues and to future food safety research directions. These include organic production, the FDA's Produce Rule (water and manure), genomic sequencing, antimicrobial resistance, and performance metrics. The concluding section emphasizes important themes such as strategic planning, coordination, epidemiology, and the need for understanding food safety production as a continuum. Food safety research, whether at the pre- or postharvest level, will continue to be a fascinating complex web of foodborne pathogens, risk factors, and scientific and policy interactions. Food safety priorities and research must continue to evolve with emerging global issues, emerging technologies, and methods but remain grounded in a multidisciplinary, collaborative, and systematic approach.
Collapse
|
16
|
Chen S, Sanderson MW, Lee C, Cernicchiaro N, Renter DG, Lanzas C. Basic Reproduction Number and Transmission Dynamics of Common Serogroups of Enterohemorrhagic Escherichia coli. Appl Environ Microbiol 2016; 82:5612-20. [PMID: 27401976 PMCID: PMC5007764 DOI: 10.1128/aem.00815-16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 07/01/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Understanding the transmission dynamics of pathogens is essential to determine the epidemiology, ecology, and ways of controlling enterohemorrhagic Escherichia coli (EHEC) in animals and their environments. Our objective was to estimate the epidemiological fitness of common EHEC strains in cattle populations. For that purpose, we developed a Markov chain model to characterize the dynamics of 7 serogroups of enterohemorrhagic Escherichia coli (O26, O45, O103, O111, O121, O145, and O157) in cattle production environments based on a set of cross-sectional data on infection prevalence in 2 years in two U.S. states. The basic reproduction number (R0) was estimated using a Bayesian framework for each serogroup based on two criteria (using serogroup alone [the O-group data] and using O serogroup, Shiga toxin gene[s], and intimin [eae] gene together [the EHEC data]). In addition, correlations between external covariates (e.g., location, ambient temperature, dietary, and probiotic usage) and prevalence/R0 were quantified. R0 estimates varied substantially among different EHEC serogroups, with EHEC O157 having an R0 of >1 (∼1.5) and all six other EHEC serogroups having an R0 of less than 1. Using the O-group data substantially increased R0 estimates for the O26, O45, and O103 serogroups (R0 > 1) but not for the others. Different covariates had distinct influences on different serogroups: the coefficients for each covariate were different among serogroups. Our modeling and analysis of this system can be readily expanded to other pathogen systems in order to estimate the pathogen and external factors that influence spread of infectious agents. IMPORTANCE In this paper we describe a Bayesian modeling framework to estimate basic reproduction numbers of multiple serotypes of Shiga toxin-producing Escherichia coli according to a cross-sectional study. We then coupled a compartmental model to reconstruct the infection dynamics of these serotypes and quantify their risk in the population. We incorporated different sensitivity levels of detecting different serotypes and evaluated their potential influence on the estimation of basic reproduction numbers.
Collapse
Affiliation(s)
- Shi Chen
- Department of Public Health Sciences, University of North Carolina Charlotte, Charlotte, North Carolina, USA Department of Population Health and Pathobiology, North Carolina State University, Raleigh, North Carolina, USA
| | - Michael W Sanderson
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, Kansas, USA
| | - Chihoon Lee
- School of Business, Stevens Institute of Technology, Hoboken, New Jersey, USA Department of Statistics, Colorado State University, Fort Collins, Colorado, USA
| | - Natalia Cernicchiaro
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, Kansas, USA
| | - David G Renter
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, Kansas, USA
| | - Cristina Lanzas
- Department of Population Health and Pathobiology, North Carolina State University, Raleigh, North Carolina, USA
| |
Collapse
|
17
|
Gil MI, Selma MV, Suslow T, Jacxsens L, Uyttendaele M, Allende A. Pre- and Postharvest Preventive Measures and Intervention Strategies to Control Microbial Food Safety Hazards of Fresh Leafy Vegetables. Crit Rev Food Sci Nutr 2014; 55:453-68. [DOI: 10.1080/10408398.2012.657808] [Citation(s) in RCA: 140] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
18
|
Larsen MH, Dalmasso M, Ingmer H, Langsrud S, Malakauskas M, Mader A, Møretrø T, Smole Možina S, Rychli K, Wagner M, John Wallace R, Zentek J, Jordan K. Persistence of foodborne pathogens and their control in primary and secondary food production chains. Food Control 2014. [DOI: 10.1016/j.foodcont.2014.03.039] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
|
19
|
|
20
|
Callaway TR, Edrington TS, Nisbet DJ. MEAT SCIENCE AND MUSCLE BIOLOGY SYMPOSIUM: Ecological and dietary impactors of foodborne pathogens and methods to reduce fecal shedding in cattle1,2. J Anim Sci 2014; 92:1356-65. [DOI: 10.2527/jas.2013-7308] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- T. R. Callaway
- Food and Feed Safety Research Unit, Southern Plains Agricultural Research Center, Agricultural Research Service, USDA, College Station, TX 77845
| | - T. S. Edrington
- Food and Feed Safety Research Unit, Southern Plains Agricultural Research Center, Agricultural Research Service, USDA, College Station, TX 77845
| | - D. J. Nisbet
- Food and Feed Safety Research Unit, Southern Plains Agricultural Research Center, Agricultural Research Service, USDA, College Station, TX 77845
| |
Collapse
|
21
|
Wells JE, Kim M, Bono JL, Kuehn LA, Benson AK. MEAT SCIENCE AND MUSCLE BIOLOGY SYMPOSIUM:Escherichia coli O157:H7, diet, and fecal microbiome in beef cattle12. J Anim Sci 2014; 92:1345-55. [DOI: 10.2527/jas.2013-7282] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- J. E. Wells
- USDA, ARS, US Meat Animal Research Center, Clay Center, NE 689334
| | - M. Kim
- USDA, ARS, US Meat Animal Research Center, Clay Center, NE 689334
| | - J. L. Bono
- USDA, ARS, US Meat Animal Research Center, Clay Center, NE 689334
| | - L. A. Kuehn
- USDA, ARS, US Meat Animal Research Center, Clay Center, NE 689334
| | - A. K. Benson
- Department of Food Science and Technology, University of Nebraska, Lincoln 68583
| |
Collapse
|
22
|
Smith DR. Cattle Production Systems: Ecology of Existing and Emerging Escherichia coli Types Related to Foodborne Illness. Annu Rev Anim Biosci 2014; 2:445-68. [DOI: 10.1146/annurev-animal-022513-114122] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Shiga toxin–producing Escherichia coli (STEC), particularly STEC O157, cause rare but potentially serious human infections. Infection with STEC occurs by fecal-oral transmission, most commonly through food. Cattle are the most important reservoir for human STEC exposure, and efforts to control the flow of STEC through beef processing have reduced rates of human illness. However, further reduction in human incidence of STEC may require control of the pathogen in cattle populations. The ecology of STEC in cattle production systems is complex and explained by factors that favor (a) colonization in the gut, (b) survival in the environment, and (c) ingestion by another cattle host. Although nature creates seasonal environmental conditions that do not favor STEC transmission in cattle, human efforts to control STEC by environmental manipulation have not succeeded. Vaccines and direct-fed microbial products have reduced the carriage of STEC by cattle, and other interventions are under investigation.
Collapse
Affiliation(s)
- David R. Smith
- Mississippi State University College of Veterinary Medicine, Mississippi State, Mississippi 39762-6100
| |
Collapse
|
23
|
Fink RC, Popowski JM, Anderson JE, Dahlberg JL, Kalyanikutty S, Crawford GI, DiCostanzo A, Cox RB, Diez-Gonzalez F. Impact of Management Practices and Distillers' Grains Feeding on the Prevalence ofEscherichia coliO157 in Feedlot Cattle in Minnesota. Foodborne Pathog Dis 2013; 10:559-65. [DOI: 10.1089/fpd.2012.1342] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Ryan C. Fink
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, Minnesota
| | - Jackie M. Popowski
- Department of Animal Science, University of Minnesota, St. Paul, Minnesota
| | - Jon E. Anderson
- Division of Mathematics and Science, University of Minnesota, Morris, Minnesota
| | - Johanna L. Dahlberg
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, Minnesota
| | - Sudha Kalyanikutty
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, Minnesota
| | - Grant I. Crawford
- Department of Animal Science, University of Minnesota, St. Paul, Minnesota
| | - Alfredo DiCostanzo
- Department of Animal Science, University of Minnesota, St. Paul, Minnesota
| | - Ryan B. Cox
- Department of Animal Science, University of Minnesota, St. Paul, Minnesota
| | | |
Collapse
|
24
|
Paddock ZD, Renter DG, Shi X, Krehbiel CR, DeBey B, Nagaraja TG. Effects of feeding dried distillers grains with supplemental starch on fecal shedding of Escherichia coli O157:H7 in experimentally inoculated steers1. J Anim Sci 2013; 91:1362-70. [DOI: 10.2527/jas.2012-5618] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Z. D. Paddock
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS 66506
| | - D. G. Renter
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS 66506
| | - X. Shi
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS 66506
| | - C. R. Krehbiel
- Department of Animal Sciences, Oklahoma State University, Stillwater, OK 74078\
| | - B. DeBey
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS 66506
| | - T. G. Nagaraja
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS 66506
| |
Collapse
|
25
|
Hallewell J, Barbieri LR, Thomas JE, Stanford K, McAllister TA. Fecal shedding in cattle inoculated with Escherichia coli O157:H7 and fed corn or wheat distillers' dried grain with solubles. J Food Prot 2013; 76:114-8. [PMID: 23317865 DOI: 10.4315/0362-028x.jfp-12-104] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Feeding corn dried distillers' grain with solubles (DDGS) has been linked to increased fecal shedding of Escherichia coli O157:H7 in cattle. A study was conducted to compare the impact of three diets containing (dry matter basis) 40% corn DDGS, 40% wheat DDGS, or 20% corn and 20% wheat mixed DDGS to a standard barley grain finishing diet on fecal shedding in cattle challenged with a 10(10) CFU mixture of four nalidixic acid-resistant E. coli O157:H7 strains. Rectal grab samples (n = 544) were collected over 70 days and screened for E. coli O157:H7 by direct plating and immunomagnetic bead separation. Feeding diets containing DDGS had no effect (P > 0.05) on the intensity or duration of fecal shedding of E. coli O157:H7 compared with the standard barley grain finishing diet.
Collapse
Affiliation(s)
- J Hallewell
- Department of Biological Sciences, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta, Canada T1K 3M4
| | | | | | | | | |
Collapse
|
26
|
Cull CA, Paddock ZD, Nagaraja T, Bello NM, Babcock AH, Renter DG. Efficacy of a vaccine and a direct-fed microbial against fecal shedding of Escherichia coli O157:H7 in a randomized pen-level field trial of commercial feedlot cattle. Vaccine 2012; 30:6210-5. [DOI: 10.1016/j.vaccine.2012.05.080] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 05/11/2012] [Accepted: 05/29/2012] [Indexed: 11/16/2022]
|
27
|
Paddock Z, Shi X, Bai J, Nagaraja T. Applicability of a multiplex PCR to detect O26, O45, O103, O111, O121, O145, and O157 serogroups of Escherichia coli in cattle feces1. Vet Microbiol 2012; 156:381-8. [DOI: 10.1016/j.vetmic.2011.11.017] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Revised: 11/18/2011] [Accepted: 11/22/2011] [Indexed: 10/14/2022]
|
28
|
Doyle MP, Erickson MC. Opportunities for mitigating pathogen contamination during on-farm food production. Int J Food Microbiol 2012; 152:54-74. [DOI: 10.1016/j.ijfoodmicro.2011.02.037] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Revised: 02/03/2011] [Accepted: 02/28/2011] [Indexed: 10/18/2022]
|
29
|
Wells JE, Shackelford SD, Berry ED, Kalchayanand N, Bosilevac JM, Wheeler TL. Impact of reducing the level of wet distillers grains fed to cattle prior to harvest on prevalence and levels of Escherichia coli O157:H7 in feces and on hides. J Food Prot 2011; 74:1611-7. [PMID: 22004806 DOI: 10.4315/0362-028x.jfp-11-160] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Cattle fed finishing diets with wet distillers grains with solubles (WDGS) have been shown to harbor increased Escherichia coli O157:H7 populations in the feces and on the hides. To determine if feeding a lower level of WDGS at the end of the feeding period reduces E. coli O157:H7 load at harvest, 608 heifers were sorted into one of five treatments and fed 0, 40, or 70% WDGS (dry matter basis). For three of the treatments, WDGS was reduced midway through the study. Treatment 0W0W heifers (positive control) were fed a corn grain-based diet continuously, and 40W40W heifers (negative control) were fed 40% WDGS continuously. Heifers subjected to treatments 40W0W, 40W15W, and 70W15W were fed either 40 or 70% WDGS for the first 56 days and switched to 0 or 15% WDGS, respectively, for the last 56 days. Prior to the switch in diets, animals fed diets with 40 or 70% had higher prevalence and percent enumerable fecal samples for E. coli O157:H7. After the dietary switch, animals fed 40W0W, 40W15W, and 70W15W diets had fecal prevalence and percent enumerable samples (33.4 and 6.3%, 31.0 and 9.7%, and 34.9 and 8.4%, respectively) similar to those of animals fed 0W0W diets (10.2 and 3.2%, respectively; P > 0.05), whereas animals fed 40W40W had the highest fecal prevalence and percent enumerable samples (70.1 and 29.2%, respectively; P < 0.05). Similar relationships between the treatments were observed for hide samples. Time after dietary switch was important, as animals fed lower levels had significantly lower fecal prevalence and percent enumerable samples after 56 days, but not after 28 days. The study indicates that cattle can be switched to lower levels of dietary WDGS (15% or less) 56 days prior to harvest to significantly reduce E. coli O157:H7 in feces and on hides.
Collapse
Affiliation(s)
- J E Wells
- U.S. Department of Agriculture, Agricultural Research Service, U.S. Meat Animal Research Center, Clay Center, Nebraska 68933-0166, USA.
| | | | | | | | | | | |
Collapse
|
30
|
Swyers KL, Carlson BA, Nightingale KK, Belk KE, Archibeque SL. Naturally colonized beef cattle populations fed combinations of yeast culture and an ionophore in finishing diets containing dried distiller's grains with solubles had similar fecal shedding of Escherichia coli O157:H7. J Food Prot 2011; 74:912-8. [PMID: 21669067 DOI: 10.4315/0362-028x.jfp-10-484] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Beef steers (n = 252) were used to evaluate the effects of dietary supplement on fecal shedding of Escherichia coli O157:H7. Seven pens of 9 steers (63 steers per treatment) were fed diets supplemented with or without yeast culture (YC) or monensin (MON) and their combination (YC × MON). YC and MON were offered at 2.8 g/kg and 33 mg/kg of dry matter intake, respectively. Environmental sponge samples (from each pen floor, feed bunk, and water trough) were collected on day 0. Rectal fecal grab samples were collected on days 0, 28, 56, 84, 110, and 125. Samples were collected and pooled by pen and analyzed for presumptive E. coli O157:H7 colonies, which were confirmed by a multiplex PCR assay and characterized by pulsed-field gel electrophoresis (PFGE) typing. On day 0, E. coli O157:H7 was detected in 7.0% of feed bunk samples and 14.3% of pen floor samples but in none of the water trough samples. The 71.4% prevalence of E. coli O157:H7 in fecal samples on day 0 decreased significantly (P < 0.05) over time. E. coli O157:H7 fecal shedding was not associated with dietary treatment (P > 0.05); however, in cattle fed YC and YC × MON fecal shedding was 0% by day 28. Eight Xba I PFGE subtypes were identified, and a predominant subtype and three closely related subtypes (differing by three or fewer bands) accounted for 78.7% of environmental and fecal isolates characterized. Results from this study indicate that feeding YC to cattle may numerically decrease but not eliminate fecal shedding of E. coli O157:H7 at the onset of treatment and that certain E. coli O157 subtypes found in the feedlot environment may persist in feedlot cattle.
Collapse
Affiliation(s)
- K L Swyers
- Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523-1171, USA
| | | | | | | | | |
Collapse
|