1
|
Rothrock MJ, Al Hakeem WG, Oladeinde A, Looft T, Li X, Guard JY. Salmonella Biomapping of a Commercial Broiler Hatchery. J Food Prot 2024; 87:100347. [PMID: 39151796 DOI: 10.1016/j.jfp.2024.100347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2024] [Revised: 08/09/2024] [Accepted: 08/12/2024] [Indexed: 08/19/2024]
Abstract
Poultry-associated salmonellosis results in significant costs to poultry producers and consumers. Given the vertically integrated nature of the United States poultry industry, a better understanding of Salmonella ecology throughout all levels of poultry production is essential. One nexus point is the hatchery, where eggs from multiple broiler breeder farms are incubated and hatched, with the chicks being sent to numerous farms; therefore, the hatchery represents an ideal area to understand preharvest Salmonella ecology and flow. To achieve this, a commercial broiler hatchery was biomapped, focusing on Salmonella prevalence and serotype diversity among four major sample type categories (Air, Egg, Water, Facility) across five different places in the prehatch, hatch, and posthatch areas. Following two sets of eggs from broiler breeder farms over two production days, the overall Salmonella prevalence was 26% (48/184). Of the positive samples, the highest prevalence was observed in swabs taken from the floor drains in the facility and transport truck (56%), as well as in the hatch and posthatch hatchery areas (50%). Kentucky (n = 17), Gaminara (n = 12), and Alachua (n = 11) were the dominant Salmonella serotypes, with serotypes of greatest outbreak concern from chickens (Enteritidis) representing only 6.25% (3/48) of all recovered Salmonella isolates. The posthatch transport area, including the underfloor reservoirs of the transport trucks, not only harbored Enteritidis but also the enrichment broths from these Salmonella-positive samples also possessed sequences matching the commercial live-attenuated vaccine Typhimurium strain according to CRISPR SeroSeq analyses. These findings highlight the complex diversity of commercial hatchery Salmonella populations, including identifying facility floor drains and transport trucks as potentially important critical control points for hatchery managers to focus their Salmonella mitigation efforts to reduce loads and serotypes entering live production farms.
Collapse
Affiliation(s)
- Michael J Rothrock
- USDA-ARS, US National Poultry Research Center, Egg & Poultry Production Safety Research Unit, Athens, Georgia, USA.
| | - Walid G Al Hakeem
- USDA-ARS, US National Poultry Research Center, Egg & Poultry Production Safety Research Unit, Athens, Georgia, USA; US-DOE, ORISE, USA
| | - Adelumola Oladeinde
- USDA-ARS, US National Poultry Research Center, Egg & Poultry Production Safety Research Unit, Athens, Georgia, USA
| | - Torey Looft
- USDA-ARS, National Animal Disease Center, Ames, Iowa, USA
| | - Xiang Li
- USDA-ARS, US National Poultry Research Center, Egg & Poultry Production Safety Research Unit, Athens, Georgia, USA
| | - Jean Y Guard
- USDA-ARS, US National Poultry Research Center, Egg & Poultry Production Safety Research Unit, Athens, Georgia, USA
| |
Collapse
|
2
|
Hu Y, Wei J, Yuan Y, Wei H, Zhou Y, Xiao N, Xiong J, Ren Z, Peng J, Cui C, Zhou Z. Intervention effects of fructooligosaccharide and astragalus polysaccharide, as typical antibiotic alternatives, on antibiotic resistance genes in feces of layer breeding: advantages and defects. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133172. [PMID: 38071777 DOI: 10.1016/j.jhazmat.2023.133172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 11/27/2023] [Accepted: 12/01/2023] [Indexed: 02/08/2024]
Abstract
Although antibiotic alternatives are widely used in livestock and poultry breeding industry after in-feed antibiotics ban, their intervention effects on antibiotic resistance genes (ARGs) in these food animals' feces remain poorly understood. Here effects of fructooligosaccharide (FOS) and astragalus polysaccharide (APS), as typical antibiotic alternatives in China, on ARGs in layer feces were estimated by performing metagenomic sequencings and fluorescence quantitative PCR. Fructooligosaccharide significantly reduced sum abundance of ARGs and mobile genetic elements (MGEs) by increasing Lactobacillus clones and reducing Escherichia clones which had relatively higher abundances of ARG subtypes and MGE subtypes in layer feces. However, at least parts of core ARGs and MGEs categories were not reduced by FOS, such as aminoglycosides- and tetracyclines-resistant genes, Tn916, Integrase, and so on. MGEs and microbiome, especially Escherichia genus and Lactobacillus genus, were the key factors affecting ARGs' sum abundance. MGEs had a higher correlation coefficient with ARGs' sum abundance than Escherichia genus and Lactobacillus genus. These findings firstly reveal the defects of antibiotic alternatives in controlling bacterial resistance in livestock and poultry breeding after in-feed antibiotics ban, and more strategies are needed to control pollutions and risks of core ARGs and MGEs in food animals' feces under a special environment.
Collapse
Affiliation(s)
- Yanping Hu
- Department of Animal Nutrition and Feed Science, College of Animal Sciences & Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Jingjing Wei
- Department of Animal Nutrition and Feed Science, College of Animal Sciences & Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yongze Yuan
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan 430079, China
| | - Hongkui Wei
- Department of Animal Nutrition and Feed Science, College of Animal Sciences & Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yuanfei Zhou
- Department of Animal Nutrition and Feed Science, College of Animal Sciences & Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Naidong Xiao
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Juan Xiong
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Zhuqing Ren
- Frontiers Science Center for Animal Breeding and Sustainable Production, Hubei Hongshan Laboratory, Huazhong Agricultural University, WuHan 430070, China
| | - Jian Peng
- Department of Animal Nutrition and Feed Science, College of Animal Sciences & Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Changzheng Cui
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Zhongxin Zhou
- Department of Animal Nutrition and Feed Science, College of Animal Sciences & Technology, Huazhong Agricultural University, Wuhan 430070, China.
| |
Collapse
|
3
|
Logue CM, De Cesare A, Tast-Lahti E, Chemaly M, Payen C, LeJeune J, Zhou K. Salmonella spp. in poultry production-A review of the role of interventions along the production continuum. ADVANCES IN FOOD AND NUTRITION RESEARCH 2023; 108:289-341. [PMID: 38461002 DOI: 10.1016/bs.afnr.2023.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/11/2024]
Abstract
Salmonella is a significant pathogen of human and animal health and poultry are one of the most common sources linked with foodborne illness worldwide. Global production of poultry meat and products has increased significantly over the last decade or more as a result of consumer demand and the changing demographics of the world's population, where poultry meat forms a greater part of the diet. In addition, the relatively fast growth rate of birds which is significantly higher than other meat species also plays a role in how poultry production has intensified. In an effort to meet the greater demand for poultry meat and products, modern poultry production and processing practices have changed and practices to target control and reduction of foodborne pathogens such as Salmonella have been implemented. These strategies are implemented along the continuum from parent and grandparent flocks to breeders, the farm and finished broilers to transport and processing and finally from retail to the consumer. This review focuses on common practices, interventions and strategies that have potential impact for the control of Salmonella along the poultry production continuum from farm to plate.
Collapse
Affiliation(s)
- Catherine M Logue
- Department of Population Health, College of Veterinary Medicine, University of Georgia, United States.
| | | | - Elina Tast-Lahti
- European Center for Disease Prevention and Control (ECDC), Sweden
| | - Marianne Chemaly
- Hygiene and Quality of Poultry and Pork Products, French Agency for Food, Environmental and Occupational Health and Safety, ANSES, France
| | - Cyrielle Payen
- Hygiene and Quality of Poultry and Pork Products, French Agency for Food, Environmental and Occupational Health and Safety, ANSES, France
| | - Jeff LeJeune
- Food System and Food Safety, Food and Agricultural Organization of the United Nations, Italy
| | - Kang Zhou
- Food System and Food Safety, Food and Agricultural Organization of the United Nations, Italy
| |
Collapse
|
4
|
Oxendine A, Walsh AA, Young T, Dixon B, Hoke A, Rogers EE, Lee MD, Maurer JJ. Conditions Necessary for the Transfer of Antimicrobial Resistance in Poultry Litter. Antibiotics (Basel) 2023; 12:1006. [PMID: 37370325 DOI: 10.3390/antibiotics12061006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 05/23/2023] [Accepted: 06/01/2023] [Indexed: 06/29/2023] Open
Abstract
Animal manures contain a large and diverse reservoir of antimicrobial resistance (AMR) genes that could potentially spillover into the general population through transfer of AMR to antibiotic-susceptible pathogens. The ability of poultry litter microbiota to transmit AMR was examined in this study. Abundance of phenotypic AMR was assessed for litter microbiota to the antibiotics: ampicillin (Ap; 25 μg/mL), chloramphenicol (Cm; 25 μg/mL), streptomycin (Sm; 100 μg/mL), and tetracycline (Tc; 25 μg/mL). qPCR was used to estimate gene load of streptomycin-resistance and sulfonamide-resistance genes aadA1 and sul1, respectively, in the poultry litter community. AMR gene load was determined relative to total bacterial abundance using 16S rRNA qPCR. Poultry litter contained 108 CFU/g, with Gram-negative enterics representing a minor population (<104 CFU/g). There was high abundance of resistance to Sm (106 to 107 CFU/g) and Tc (106 to 107 CFU/g) and a sizeable antimicrobial-resistance gene load in regards to gene copies per bacterial genome (aadA1: 0.0001-0.0060 and sul1: 0.0355-0.2455). While plasmid transfer was observed from Escherichia coli R100, as an F-plasmid donor control, to the Salmonella recipient in vitro, no AMR Salmonella were detected in a poultry litter microcosm with the inclusion of E. coli R100. Confirmatory experiments showed that isolated poultry litter bacteria were not interfering with plasmid transfer in filter matings. As no R100 transfer was observed at 25 °C, conjugative plasmid pRSA was chosen for its high plasmid transfer frequency (10-4 to 10-5) at 25 °C. While E. coli strain background influenced the persistence of pRSA in poultry litter, no plasmid transfer to Salmonella was ever observed. Although poultry litter microbiota contains a significant AMR gene load, potential to transmit resistance is low under conditions commonly used to assess plasmid conjugation.
Collapse
Affiliation(s)
- Aaron Oxendine
- School of Animal Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA
| | - Allison A Walsh
- School of Animal Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA
| | - Tamesha Young
- School of Animal Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA
| | - Brandan Dixon
- School of Animal Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA
| | - Alexa Hoke
- School of Animal Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA
| | - Eda Erdogan Rogers
- Department of Biomedical Science and Pathobiology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA
| | - Margie D Lee
- Department of Biomedical Science and Pathobiology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA
| | - John J Maurer
- School of Animal Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA
| |
Collapse
|
5
|
Calderón-Franco D, van Loosdrecht MCM, Abeel T, Weissbrodt DG. Catch me if you can: capturing microbial community transformation by extracellular DNA using Hi-C sequencing. Antonie Van Leeuwenhoek 2023:10.1007/s10482-023-01834-z. [PMID: 37156983 DOI: 10.1007/s10482-023-01834-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 04/24/2023] [Indexed: 05/10/2023]
Abstract
The transformation of environmental microorganisms by extracellular DNA is an overlooked mechanism of horizontal gene transfer and evolution. It initiates the acquisition of exogenous genes and propagates antimicrobial resistance alongside vertical and conjugative transfers. We combined mixed-culture biotechnology and Hi-C sequencing to elucidate the transformation of wastewater microorganisms with a synthetic plasmid encoding GFP and kanamycin resistance genes, in the mixed culture of chemostats exposed to kanamycin at concentrations representing wastewater, gut and polluted environments (0.01-2.5-50-100 mg L-1). We found that the phylogenetically distant Gram-negative Runella (102 Hi-C links), Bosea (35), Gemmobacter (33) and Zoogloea (24) spp., and Gram-positive Microbacterium sp. (90) were transformed by the foreign plasmid, under high antibiotic exposure (50 mg L-1). In addition, the antibiotic pressure shifted the origin of aminoglycoside resistance genes from genomic DNA to mobile genetic elements on plasmids accumulating in microorganisms. These results reveal the power of Hi-C sequencing to catch and surveil the transfer of xenogenetic elements inside microbiomes.
Collapse
Affiliation(s)
| | | | - Thomas Abeel
- Delft Bioinformatics Lab, Delft University of Technology, Delft, The Netherlands
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - David G Weissbrodt
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands.
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, Trondheim, Norway.
| |
Collapse
|
6
|
Zwirzitz B, Oladeinde A, Johnson J, Zock G, Milfort MC, Fuller AL, Ghareeb AFA, Foutz JC, Teran JA, Woyda R, Abdo Z, Looft T, Lawrence JP, Cudnik D, Aggrey SE. Temporal dynamics of the cecal and litter microbiome of chickens raised in two separate broiler houses. Front Physiol 2023; 14:1083192. [PMID: 36935743 PMCID: PMC10018173 DOI: 10.3389/fphys.2023.1083192] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 02/20/2023] [Indexed: 03/06/2023] Open
Abstract
In this study, we investigated the dynamics of the ceca and litter microbiome of chickens from post-hatch through pre-harvest. To achieve this, six hundred one-day old Cobb 500 broiler chicks were raised on floor pens for 49 days in two separate houses. We performed short-read and full-length sequencing of the bacterial 16S rRNA gene present in the meconium and in cecal and litter samples collected over the duration of the study. In addition, we determined the antimicrobial resistance (AMR) phenotype of Escherichia coli and Enterococcus spp. isolated from the meconium and the ceca of 49-day old chickens. We monitored the relative humidity, temperature, and ammonia in each house daily and the pH and moisture of litter samples weekly. The overall microbial community structure of the ceca and litter consistently changed throughout the course of the grow-out and correlated with some of the environmental parameters measured (p < 0.05). We found that the ceca and litter microbiome were similar in the two houses at the beginning of the experiment, but over time, the microbial community separated and differed between the houses. When we compared the environmental parameters in the two houses, we found no significant differences in the first half of the growth cycle (day 0-21), but morning temperature, morning humidity, and ammonia significantly differed (p < 0.05) between the two houses from day 22-49. Lastly, the prevalence of AMR in cecal E. coli isolates differed from meconium isolates (p < 0.001), while the AMR phenotype of cecal Enterococcus isolates differed between houses (p < 0.05).
Collapse
Affiliation(s)
- Benjamin Zwirzitz
- Department of Food Science and Technology, Institute of Food Science, University of Natural Resources and Life Sciences, Vienna, Austria
- Austrian Competence Centre for Feed and Food Quality, Safety and Innovation FFoQSI GmbH, Tulln, Austria
| | | | - Jasmine Johnson
- Department of Poultry Science, University of Georgia, Athens, GA, United States
| | - Gregory Zock
- Department of Poultry Science, University of Georgia, Athens, GA, United States
| | - Marie C. Milfort
- Department of Poultry Science, University of Georgia, Athens, GA, United States
| | | | - Ahmed F. A. Ghareeb
- Department of Poultry Science, University of Georgia, Athens, GA, United States
| | - James C. Foutz
- Department of Poultry Science, University of Georgia, Athens, GA, United States
| | - Jose Alexis Teran
- College of Engineering, University of Georgia, Athens, GA, United States
| | - Reed Woyda
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
- Program of Cell and Molecular Biology, Colorado State University, Fort Collins, CO, United States
| | - Zaid Abdo
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
- Program of Cell and Molecular Biology, Colorado State University, Fort Collins, CO, United States
| | - Torey Looft
- USDA-ARS, National Animal Disease Center, Ames, IA, United States
| | | | - Denice Cudnik
- USDA-ARS, U.S. National Poultry Research Center, Athens, GA, United States
| | - Samuel E. Aggrey
- Department of Poultry Science, University of Georgia, Athens, GA, United States
| |
Collapse
|
7
|
Chicken Production and Human Clinical Escherichia coli Isolates Differ in Their Carriage of Antimicrobial Resistance and Virulence Factors. Appl Environ Microbiol 2023; 89:e0116722. [PMID: 36651726 PMCID: PMC9973021 DOI: 10.1128/aem.01167-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Contamination of food animal products by Escherichia coli is a leading cause of foodborne disease outbreaks, hospitalizations, and deaths in humans. Chicken is the most consumed meat both in the United States and across the globe according to the U.S. Department of Agriculture. Although E. coli is a ubiquitous commensal bacterium of the guts of humans and animals, its ability to acquire antimicrobial resistance (AMR) genes and virulence factors (VFs) can lead to the emergence of pathogenic strains that are resistant to critically important antibiotics. Thus, it is important to identify the genetic factors that contribute to the virulence and AMR of E. coli. In this study, we performed in-depth genomic evaluation of AMR genes and VFs of E. coli genomes available through the National Antimicrobial Resistance Monitoring System GenomeTrackr database. Our objective was to determine the genetic relatedness of chicken production isolates and human clinical isolates. To achieve this aim, we first developed a massively parallel analytical pipeline (Reads2Resistome) to accurately characterize the resistome of each E. coli genome, including the AMR genes and VFs harbored. We used random forests and hierarchical clustering to show that AMR genes and VFs are sufficient to classify isolates into different pathogenic phylogroups and host origin. We found that the presence of key type III secretion system and AMR genes differentiated human clinical isolates from chicken production isolates. These results further improve our understanding of the interconnected role AMR genes and VFs play in shaping the evolution of pathogenic E. coli strains. IMPORTANCE Pathogenic Escherichia coli causes disease in both humans and food-producing animals. E. coli pathogenesis is dependent on a repertoire of virulence factors and antimicrobial resistance genes. Food-borne outbreaks are highly associated with the consumption of undercooked and contaminated food products. This association highlights the need to understand the genetic factors that make E. coli virulent and pathogenic in humans and poultry. This research shows that E. coli isolates originating from human clinical settings and chicken production harbor different antimicrobial resistance genes and virulence factors that can be used to classify them into phylogroups and host origins. In addition, to aid in the repeatability and reproducibility of the results presented in this study, we have made a public repository of the Reads2Resistome pipeline and have provided the accession numbers associated with the E. coli genomes analyzed.
Collapse
|
8
|
Abstract
Chickens are in constant interaction with their environment, e.g., bedding and litter, and their microbiota. However, how litter microbiota develops over time and whether bedding and litter microbiota may affect the cecal microbiota is not clear. We addressed these questions using sequencing of V3/V4 variable region of 16S rRNA genes of cecal, bedding, and litter samples from broiler breeder chicken flocks for 4 months of production. Cecal, bedding, and litter samples were populated by microbiota of distinct composition. The microbiota in the bedding material did not expand in the litter. Similarly, major species from litter microbiota did not expand in the cecum. Only cecal microbiota was found in the litter forming approximately 20% of total litter microbiota. A time-dependent development of litter microbiota was observed. Escherichia coli, Staphylococcus saprophyticus, and Weissella jogaejeotgali were characteristic of fresh litter during the first month of production. Corynebacterium casei, Lactobacillus gasseri, and Lactobacillus salivarius dominated in a 2-month-old litter, Brevibacterium, Brachybacterium, and Sphingobacterium were characteristic for 3-month-old litter, and Salinococcus, Dietzia, Yaniella, and Staphylococcus lentus were common in a 4-month-old litter. Although the development was likely determined by physicochemical conditions in the litter, it might be interesting to test some of these species for active modification of litter to improve the chicken environment and welfare. IMPORTANCE Despite intimate contact, the composition of bedding, litter, and cecal microbiota differs considerably. Species characteristic for litter microbiota at different time points of chicken production were identified thus opening the possibility for active manipulation of litter microbiota.
Collapse
|
9
|
Management and environmental factors influence the prevalence and abundance of food-borne pathogens and commensal bacteria in peanut hull-based broiler litter. Poult Sci 2022; 102:102313. [PMID: 36502564 PMCID: PMC9758567 DOI: 10.1016/j.psj.2022.102313] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/29/2022] [Accepted: 11/01/2022] [Indexed: 11/06/2022] Open
Abstract
In this study, we conducted a longitudinal sampling of peanut hull-based litter from a farm under a "no antibiotics ever" program. Our objective was to determine broiler management practices and environmental factors that are associated with the occurrence of food-borne pathogens (Salmonella and Campylobacter) and the abundance of commensal bacteria (Escherichia coli, Enterococcus spp., and Staphylococcus spp.). Litter (n = 288) was collected from 4 broiler houses over three consecutive flocks, starting with a complete house cleanout and fresh peanut hull. Litter was sampled at the beginning of each grow-out cycle and at the end of the cycle. Logistic and linear regression models were used to model the relationships between pathogen prevalence, commensal abundance and management practices, and environmental factors. The number of flocks raised on litter, grow-out period, broiler house, litter pH, litter moisture, and house temperature were associated with the prevalence of pathogens and the abundance of commensal bacteria in litter. The final logistic model for pathogens showed that a higher probability of detecting Salmonella in litter was associated with the number of flocks raised on litter and the grow-out period. A higher probability of detecting Campylobacter in litter was associated with the number of flocks raised on litter, broiler house and the sections of the house, and the pH of litter. Our results suggest that management practices and environmental factors affect Salmonella and Campylobacter differently and suggest that each pathogen will require its own tailored intervention to stop their persistence in broiler litter.
Collapse
|