Submitted to: International Poultry Forum Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: January 20, 2003
Publication Date: May 1, 2003
Citation: Mclaughlin, M.R., El Balaa, M.F., Rowe, D.E., Doerner, K.C., King, R., Andersland, J. 2003. Isolation of lytic salmonella bacteriophages [abstract]. Poultry Science 82(supplement 1):140.
Interpretive Summary: None required.
This research was based on the hypothesis that Salmonella bacteriophages (phages) occur naturally in manure and can be isolated for future characterization and potential use as typing reagents, indicators and biocontrol agents. The purpose of this research was to test a protocol for isolation of lytic Salmonella phages. Samples collected from lagoons on commercial hog farms in Mississippi were processed as follows. Subsamples were transferred to sterile glass tubes and mixed with chloroform to kill vegetative bacteria. Chloroform and aqueous phases were allowed to separate and samples were passed through 0.22 micron filters to remove chloroform-resistant spores. Samples were pooled for each lagoon. Salmonella phages were selectively enriched by mixing pooled samples with double strength trypticase soy broth inoculated with a Salmonella cocktail, containing S. typhimurium (ATCC 43971 and ATCC 14028) and S. enteritidis (ATCC 13076). After 17 hr incubation at 37 C chloroform was added and samples were stored at 5 C. Dilutions of enriched samples were prepared in saline and tested by double agar layer plaque assay with individual Salmonella isolates. Test samples were combined with bacterial suspensions in soft trypticase soy agar (TSA) at 45 C. The soft agar mixture was poured over the surface of hardened TSA in a Petri dish and allowed to harden and dry. Plates were incubated inverted at 35 C and plaques counted after 12 hr. Phage titers of 2.9 x 10^8 to 2.1 x 10^9 plaque forming units per ml were produced in the enriched samples. Swine lagoon effluent was a good source of Salmonella phages and the isolation and enrichment protocol produced high titers of phages for further characterization and research.