Progress 02/01/16 to 01/31/17
Target Audience:Data from this project was presented at the Conference of Research Workers in Animal Diseases which represents a group of scientists that work in the field of animal diseases. Some of the data also was presented at the the Western Canadian Association of Swine Veterinarians (Saskatoon, Sask). This group was a mix of practioneers and researchers. The work also was pesented at the 2016 Leman Conference. This conference is for swine practioneers, regulators, and researchers. Changes/Problems:No major problems were encountered. We have decided to perform some additional in vitro challenge work using IPEC (pig intestinal epithelia cells) to determine if the reason whyLawsoniaaffectsSalmonella? is due to suppression of host inflammatory responses. What opportunities for training and professional development has the project provided?In addition to the graduate student assigned to this project, several other graduate students and a veterinary student were involved in the sample sampling aspects of the project and gave them experience handling pigs. How have the results been disseminated to communities of interest?See the list of abstracts. This work was presented at three scientific meetings (Leman Conference, Conference of Research Workers in Animal Diseases, and the Western Canadian Association of Swine Veterinarians. What do you plan to do during the next reporting period to accomplish the goals?The third specific aim was to measure gut microbiome differences in pigs challenged withSalmonella, SalmonellaandLawsoniawith or without vaccination. Fecal samples have already been collected and are being sequenced to measure if vaccination leads to the prevention of microbiome changes previously observed after challenges withSalmonella, Lawsonia,?or both.
What was accomplished under these goals?
During the previous year, aims #1 and #2 were completed. Pigs were challenged with Salmonella or Salmonella and Lawsonia and shedding of Salmonella followed over time by using a most probable number culture system from collected feces. The pig prevalence of Salmonella shedding also was monitored. In preliminary experiments where the experimental sample was tissue (jejunum, ileum, cecum, and colon) and where there was as significant increase in shedding ofSalmonellaby pigs infected with bothSalmonellaandLawsonia, in the current trial, that difference was not observed. This probably is the result of sample differences - tissue samples versus feces. In the second aim we vaccinated pigs with aLawsoniavaccine and comparedSalmonellashedding in singly or dually infected pigs to determine if vaccination reduced shedding of Salmonella. Vaccination caused a significant reduction on the shedding ofSalmonellain pigs also challenged withLawsonia.The vaccine had no effect on shedding if the pigs were only challenged withSalmonella. The pig prevalence of shedding ofSalmonellaalso was significantly reduced in vaccinated and dually challenged pigs. Our overall conclusion was that vaccination againstLawsoniamight be an effective means to reduceSalmonellashedding if pigs are likely infected withLawsoniatoo. Since herd prevalence forLawsoniain US herds is near 90%, it is likely thatSalmonellainfected pigs also will be infected withLawsonia.
Conference Papers and Presentations
1. Leite, F.L.L, Connie Gebhart, C., Singer, R., Isaacson, R. Vaccination against Lawsonia intracellularis leads to decreased Salmonella enterica serovar Typhimurium shedding in co-infected animals. Leman Conference, St. Paul, MN, 2016.
2. Leite, F.L.L, Connie Gebhart, C., Singer, R., Isaacson, R. Vaccination against Lawsonia intracellularis leads to decreased Salmonella enterica serovar Typhimurium shedding in co-infected animals. Conference of Research Workers in Animal Diseases, Chicago, IL, 2016.
Progress 02/01/15 to 01/31/16
Target Audience:Academic research community, government basic and applied researchers, industry related to animal health and food safety. Changes/Problems:Three changes were made to the protocol. The first was that the determination of length ofS. entericashedding was combined with the vaccination study. This was performed since the length of shedding aspect was as part of both aims 1 and 2. This allows us to be more cost effective. The second change is that we had specified groups being composed of 10 pigs per treatment. However, the animal isolation space available to us does not permit that many pigs per room. Therefore, we have increased the number of groups by 3 fold but reduced group size to 3 pigs each. This allows us to perform the same work but also allows us to measure whether there were pen effects unrelated to the treatments. The final change is that peripheral blood also is being collected and the blood will be used to determine if any of the protocols result in increased production of pro-inflammatory cytokines or antiinflammatory cytokines. While not part of the original proposal, these extra measures with allow us to determine if the innate immune response is partly involved in enhanced shedding ofS. entericain the dualling infected pigs. What opportunities for training and professional development has the project provided?One graduate student (Ph.D.) is assigned to this project and will be the basis for his thesis. He is being trained in microbiology, infectious diseases, microbiome analysis, and animal health/food safety. In addition, 2-3 other students (graduate and veterinary) will be involved in sample collection and the work will contribute to their respective training in microbiology, infectious diseases, and animal science. How have the results been disseminated to communities of interest?
What do you plan to do during the next reporting period to accomplish the goals?As stated in results, pigs have been received to initiate work on all three specific aims. Pigs are being randomized into various groups for different treatments and vaccinations withLawsonia intracellularisvaccine and challenges withLawsonia intracellularis, Salmonella entericaserovar Typhimurium or both will begin January 22, 2016. Besides determining the length of enhanced shedding ofS. entericawhen co-challenged withL.intracellularis, the initial challenges also will be used to determine if vaccination abborgates enhanced shedding ofS. enterica? and fecal samples will be collected to determine the composition of the fecal microbiome. We anticipate that by the end of the current reporting period that we will have confirmed our initial results thatL.intracellularisenhances shedding of S. enterica. We also will have a first trial to determine if anti-L. intracellularisvaccination reduces shedding ofS. enterica.Finally, fecal samples will have been processed and the first analyses of microbiomes in the groups will be completed.
What was accomplished under these goals?
Pigs have been received to initiate work on all three specific aims. Pigs are being randomized into various groups for different treatments and vaccinations with Lawsonia intracellularis vaccine and challenges with Lawsonia intracellularis, Salmonella enterica serovar Typhimurium or both will begin January 22, 2016. Besides determining the length of enhanced shedding ofS. entericawhen co-challenged withL.intracellularis, the initial challenges also will be used to determine if vaccination abborgates enhanced shedding ofS. enterica? and fecal samples will be collected to determine the composition of the fecal microbiome.
Borewicz, K.A., Kim, H.B., Singer, R.S., Gebhart, C.J., Sreevatsan, S., Johnson, T., and Isaacson, R.E. Changes in the porcine intestinal microbiome in response to infection with Salmonella enterica and Lawsonia intracellularis. PLOS One, 10(10): e0139106.doi:10.1371/journal.pone.0139106.