Location: Produce Safety and Microbiology ResearchTitle: A lytic bacteriophage isolated from non-animal origin has better biocontrol features than a bacteriophage isolated from bovine feces to control Shiga toxin-producing Escherichia coli O157:H7
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/2/2020
Publication Date: N/A
Interpretive Summary: N/A
Technical Abstract: Introduction: Shiga toxin-producing Escherichia coli (STEC) O157 has been associated with numerous foodborne outbreaks since 1982. Increasing numbers of bacteriophages have been isolated to combat STEC strains to reframe from the potential development of antibiotics-resistant strains. A high diversity of lytic bacteriophages is preferable for the biocontrol application and are likely related to different sources of isolation. However, many bacteriophages specific to these pathogens were isolated from the animal-associated samples, such as feces, but rarely from non-animal sources. Objective: The objectives of this study were to characterize and compare two lytic phages isolated from different environments for biocontrol of STEC O157:H7. Methods: Phages G157 and UDF157 were isolated from non-fecal compost and bovine feces, respectively. After purification, both phages were subjected to further characterization, such as host range tests against three non-pathogenic E. coli and 14 Shiga toxin-producing E. coli O157 and top six non-O157 strains, antimicrobial analysis using a spectrophotometer, UV stability (at a wavelength of 278 nm) tests, and stx genes screening. The morphology of the phage was also obsrrved using transmission electron microscopy. Results: Phages G157 and UDF157 belonged to Myoviridae and Siphoviridae families, respectively. Both phages were negative of stx genes. Phage G157 was able to infect STEC O157 (strong lysis), E. coli O157:H7 without stx genes (ATCC43888; strong lysis), and STEC O103 (medium lysis) strains, whereas phage UDF 157 only infected STEC O157 (strong lysis) and generic E. coli (ATCC13706; medium lysis). Additionally, phage UDF157 has a stronger antimicrobial activity than G157 against STEC O157 strains. Furthermore, phage G157 was more resistant to UV treatment than UDF157. Significance: The finding of the study shows that the phage isolated from the sample of non-animal origin has the biological features, including host range, antimicrobial activity, and stress stability, more suitable for controlling STEC O157 strains than the phage isolated from bovine feces.