Location: Food and Feed Safety Research
2017 Annual Report
Objectives
Objective 1: Define the differential host-pathogen interactions between Salmonella and chicken and poultry mucosal immune systems using genomic technologies. Determine the relationship between foodborne pathogens and the mucosal innate immune response, focusing on epigenetic reprogramming of host immune genes in persistent infections.
Objective 2: Identify and develop key strategies including waste, vaccination (using innate immunity), and lighting management strategies for use at animal production facilities that mitigate and reduce the bacterial load of Salmonella and other foodborne pathogens without the use of antibiotics during pre-harvest production in broiler chickens and turkeys.
Objective 3: Analyze and characterize both host and Salmonella proteins that are modulated in expression during infection using quantitative proteomic. Develop strategies to reduce foodborne pathogens by targeting host immune-metabolic signaling pathways affected by Salmonella and Campylobacter virulence factors.
Objective 4: Investigate potential alternatives to antibiotics, such as chitosan preparations and other commercially available products, on the cecal levels of Salmonella and Campylobacter using an experimental model and metagenomics. Investigate the potential for use and the mechanism used by specific nutritional supplements to inhibit the transfer of genetic resistance elements, such as plasmids, by conjugation between commensal and foodborne bacteria.
Objective 5: Investigate the interaction between yeast and fungi and foodborne bacteria to determine their role as commensals and inhibitors or their use as alternatives to antibiotics as pre-and probiotics.
Objective 6: Identify ecological reservoirs of pathogens and the potential role of dispersal of animal waste that enable the retention of foodborne pathogens within animal production facilities and the surrounding environments.
Approach
The Centers for Disease Control and Prevention continues to monitor multistate foodborne outbreaks that impact health of the nation over the last 10 years. One area of concern is the reduction of Salmonella as a foodborne pathogen. Despite control efforts that cost over a half a billion dollars annually, foodborne illnesses due to Salmonella continues to impact the consumer. Poultry are commonly identified as a major source of Salmonella. To develop urgently needed new control strategies against Salmonella, we will take a multi-faceted, but integrated approach to identify and evaluate factors at the pre-harvest level that can be used. Based on previous research and collaborations with industry, we will identify and modify management practices that may decrease foodborne pathogen load, as well as environmental conditions associated with higher risk that would be conducive to pathogen survival and growth. Cost effective alternatives will be suggested throughout the poultry production phase. Environmental areas of concern, such as poultry waste and insect vectors will be included. At a more micro-level, interactions among fungi, protozoa, and other microbes will be evaluated under commercial production practices with the outcome of proposed new strategies for pathogen reduction. Campylobacter, a foodborne pathogen in poultry, has become an increasing concern due to the development of antibiotic resistance, especially to fluoroquinolones. The proposed research will investigate strategies to reduce pre-harvest Campylobacter, which will enhance the microbiological safety of poultry. This is important for food safety, but also for the reduction of potential antimicrobial resistance in animal agriculture and public health. Immune modulation is one approach for new anti-infective therapies, whereby natural mechanisms in the host can be exploited to strengthen therapeutic benefits. The stimulation of innate immunity has considerable potential to induce a profound and rapid cross-protection against multiple serovars of bacteria. Using "omic" techniques, including functional genomics, epigenetics, proteomics, and metabolomics, we will identify effective modulators of innate immunity to control infections, especially in situations where vaccination is not appropriate. Furthermore, metabolism and host immunity are essential requirements for survival. Mounting an immune response requires major changes to metabolic processes. Thus, the integration of central metabolic pathways and nutrient sensing with antibacterial immunity alters cellular energy homeostasis and contributes to the prevention or resolution of infectious diseases. Hence, immune and metabolic response processes govern infectious diseases. Research taken will focus on obtaining a greater understanding of the critical nodes of immunometabolism during Salmonella and Campylobacter infection.
Progress Report
In FY 2017, focus was on implementing management strategies for reducing the movement of bacteria from the poultry house environment. As part of project work to reduce the spread of foodborne pathogens, studies were conducted to examine the impact that types of lighting (LED versus florescent) may have on foodborne pathogens in poultry (Objective 1). The results indicate that the spectrum of LED light can affect the cecal Salmonella contamination when combined with Salmonella Enteritidis-vaccinated laying hens. Work also assessed the role of arthropods at animal production facilities and their influence on pathogen transmission. Work in FY 2017 advanced the understanding of the fate and transport of bacteria by arthropods and led to a better knowledge base for development of new procedures and protocols for controlling foodborne pathogens (Objectives 2 and 3). In other work during FY 2017, feeding of certain bacterial and fungal products to broiler chickens improved overall animal health and welfare as measured by evaluation of stress indicators while the birds were under heat stress or non-heat stress conditions. Fungal products may be useful as a means to improve poultry welfare by reducing stress susceptibility (Objective 4).
Accomplishments
1. Filth fly transmission of Escherichia coli O157:H7 and Salmonella enterica. Much needs to be learned about the roles arthropods play in animal production facilities regarding the transfer of food poisoning microbes. ARS researchers at College Station, Texas, characterized the differential capacity of the blow fly and the house fly to acquire and deposit E. coli O157:H7 or Salmonella. House flies have historically been implicated in pathogen contamination, but data from this work indicates that blowflies are more efficient vectors of foodborne pathogens. The vectoring capacities of different insects exposed to the same pathogen may not be equal, and different pathogens may not be equally vectored by a given insect species. This knowledge is important in developing strategies for arthropod/pathogen management in and around poultry rearing facilities.
2. Interkingdom cues by bacteria associated with filth fly behavior. Mechanisms that regulate insect succession on carrion, which affects decomposition rates and pathogen dispersal, are poorly understood. ARS researchers at College Station, Texas, examined the succession responses of the native secondary screwworm and the invasive hairy maggot blowfly to colonization of resources when in direct competition. The flies exhibited differential responses to eggs from their species versus competing species, which appears to be a result of microbial produced odors that are tied into the predator-prey interactions between the species. Analysis revealed the blow fly had similar egg-associated microbes that may serve as camouflage, allowing the predator fly to colonize and attract the prey for its larvae. This work suggests that insect and microbial interactions may have broader impacts on carcass decomposition and could allow direct intervention of insect attraction to waste and pathogen dispersal at food animal production facilities.
Review Publications
Pace, R.C., Talley, J.L., Crippen, T.L., Wayadande, A.C. 2017. Filth fly transmission of Escherichia coli O157:H7 and Salmonella enterica to lettuce, Lactuca sativa. Annals of the Entomological Society of America. 110(1):83-89.
Brundage, A.L., Crippen, T.L., Singh, B., Benbow, E., Liu, W., Tarone, A.M., Wood, T.K., Tomberlin, J.K. 2017. Interkingdom cues by bacteria associated with conspecific and heterospecific eggs of Cochliomyia macellaria and Chrysomya rufifacies (Diptera: Calliphoridae) potentially govern succession on carrion. Annals of the Entomological Society of America. 110(1):73-82. doi:10.1093/aesa/saw090.
Castaneda Correa, A., Trachsel, J., Allen, H.K., Corral-Luna, A., Gutierrez-Banuelos, H., Ochoa-Garcia, P.A., Ruiz-Barrera, O., Hume, M.E., Callaway, T.R., Harvey, R.B., Beier, R.C., Anderson, R.C., Nisbet, D.J. 2017. Effect of sole or combined administration of nitrate and 3-nitro-1-propionic acid on fermentation and Salmonella survivability in alfalfa-fed rumen cultures in vitro. Bioresource Technology. 229:69-77. doi: 10.1016/j.biortech.2017.01.012.
Silva-Vazquez, R., Garcia-Macias, J.A., Duran-Melendez, L.A., Hume, M.E., Mendez-Zamora, G. 2017. Mexican oregano (Lippia berlandieri Schauer) oil on turkey slaughter quality. Ecosistemas y Recursos Agropecuarios. 4(10):177-182.
Kogut, M.H., Byrd, J.A. 2016. The relationship between the immune response and susceptibility to Salmonella enterica serovar Enteritidis infection in the laying hen. In: Ricke, S.C., Gast, R.K., editors. Producing Safe Eggs. London, UK: Elsevier Inc. p. 209-234.
