The use of bacteriophages is considered as a viable alternative to chemical antimicrobials against foodborne pathogens. The objective of this study was to develop a collection of lytic bacteriophages which will be able to infect different pathogenic Salmonella enterica serovars. Phages were isolated from animal feces and sewage samples, purified, characterized morphologically and by DNA fingerprinting, and host ranges were determined. Spot test and efficiency of plaquing (EOP) data indicated that two phages, SEA1 and SEA2 had the broadest host range against Salmonella among all isolated phages. SEA2 was highly efficient to infect S. Typhimurium DT104 (0.5-1 EOP value). Only phage SSA1 was able to infect S. Montevideo. Transmission electron microscopy (TEM) revealed the phages in the collection were mostly (4 out of 6) Siphoviridae, while SEA1 and SEA2 were Myoviridae T4-like phages. SEA1 and SEA2 had the largest genome sizes in the collection, 190 and 170kb, respectively. Pulsed field gel electrophoresis (PFGE) analysis demonstrated distinct digestion profiles with EcoRI for phages SSA1, STD3, STE3 and STF1. However, SEA1 and SEA2 shared a similar restriction enzyme (RE) digestion pattern with same morphotype, but distinct profiles in lysing Salmonella strains. These anti- Salmonella phages were highly host specific with few exceptions of lytic phages that were able to infect a wide variety of Salmonella. These phages have potential for use in applications controlling Salmonella on different matrices.
Bibliographical noteFunding Information:
We thank Mike Magee and Mike Larose, Rice Lake Wastewater Treatment facilities, Rice Lake, WI for their cooperation and help to provide sewage samples for this study. We would like to thank Dr. Andrew Brabban and Dr. Elizabeth Kutter of Evergreen State College, WA for all of their suggestions help with developing the methods. This project was funded by the USDA's Integrated Organic Program under award No. 2007-51300-03796.
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- Anti-Salmonella phages
- Food safety