|Donoghue, Ann - Annie|
Submitted to: Food Safety Consortium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 9/30/2003
Publication Date: 10/2/2003
Citation: Hargis, B., Donoghue, D.J., Newberry, L.A., Huff, W.E., Donoghue, A.M., Higgins, S.E., Bielke, L.R., Sartor, C.D. 2003. Evaluation of bacteriophage strategies for controlling antemortem infection and postmortem contamination with salmonella in commercial poultry. In: Proceedings of the Food Safety Consortium, October 12-14, 2003, Fayetteville, Arkansas. 2003 CDROM.
Technical Abstract: Bacteriophages are potentially a safe antibiotic alternative because they attach and lyse only bacterial cells, posing no risk to the animal host. Bacteriophages are believed to generally be very host specific (Ackermann et al., 1978). However, past research has shown this is not always the case (Greene and Goldberg 1985), and Jensen et al. 1998). Previously in our laboratory we isolated bacteriophages from waste water which lyse a primary poultry isolate of Salmonella enteritidis (SE). We evaluated the host range of two bacteriophage isolates and found that they have the abiity to also lyse up to 7 other Salmonella isolates when plated using soft agar overlay technique. Further, we found that addition of bacteriophage to carcass rinse samples significantly reduced the amount of recoverable Salmonella in both laboratory and field trial settings. all bacteriophage treatments reduced (p<0.05) frequency of Salmonella recovered as compared to controls. We have developed a method to select bacteriophages for effective therapeutic use in poults. Using poults as a biological filter, we administered bacteriophages orally and then recovered phages from the ileum and ceca. We selected phages by 3 serial passages in 3 poults each passage. Use of selected bacteriophages to treat SE challenged poults resulted in reduction of SE in the ceca as compared to the non-treated controls in two replicate experiments. Finally, we have isolated non-host-specific bacteriophages using a simple selection assay. The 44 resulting bacteriophages were then selected for their ability to also amplify in alternate host bacteria isolated from the gastrointestinal tract of poultry. Four bacteriophages exhibitd the ability to amplify in more than one genus of bacteria in two separate experiments. Two of the resulting four wide-host-range bacteriophages were further tested for their ability to amplify in ten different Salmonella field isolates. One bacteriophage was able to amplify in six different Salmonella isolates, and the second bacteriophage was able to amplify in two different Salmonella isolates. The same two bacteriophage isolates were also tested for their ability to survive passage through the gastrointestinal tract of chicks when combined with their alternative-host bacteria. Previous studies in our laboratory have shown that bacteriophages are susceptable to the low pH conditions of the upper GIT, with very few (<10/mL) surviving passage. Utilizing the alternative-host bacteria as a carrier to protect internalized bacteriophages from the harsh conditions of the upper GIT, could allow more bacteriophages to reach the lower GIT, a common site for Salmonella infection in poultry.