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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Produce Safety and Microbiology Research » Research » Publications at this Location » Publication #372243

Research Project: Ecology and Detection of Human Pathogens in the Produce Production Continuum

Location: Produce Safety and Microbiology Research

Title: Phage therapy for controlling Shiga toxin-producing Escherichia coli O103 using lytic bacteriophages

item ZHANG, YUJIE - Shanghai Ocean University
item Liao, Yen-Te
item Salvador, Alexandra
item LAVENBURG, VALERIE - Volunteer
item Harden, Leslie - Les
item Wu, Vivian

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 12/5/2019
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Shiga toxin-producing Escherichia coli (STEC) O103 is one of the most prevalent non-O157 serogroups associated with multistate foodborne outbreaks in the United States. Due to the emergence of antibiotic-resistant strains, lytic phages have been considered as promising biocontrol potential agents to combat bacterial pathogens. However, very few phages specific to STEC O103 have been characterized and evaluated for their antimicrobial effects. Thus, the objective of this study was to characterize two bacteriophages isolated from environmental samples for phage therapy of STEC O103 pathogens. Escherichia phages Ro103C3lw and Pr103Blw were isolated from non-fecal compost and cattle feces, respectively. The purified phages were subjected to whole-genome sequencing by Illumina MiSeq, biological characterization, such as one-step growth curve, and antimicrobial activity test against pathogenic E. coli strains. Subsequently, the lysogeny test of two phages was evaluated by infection of the strain and genomic analysis. Podophage Ro103C3lw and myophage Pr103Blw contained double-stranded DNA with a genome size of 39,389-bp and 88,421-bp, respectively. Among the coding regions (CDSs) of Ro103C3lw (n=51) and Pr103Blw (n=113), no CDS associated with virulent, antibiotic-resistant, and lysogenic factors were detected. Both phage Ro103C3lw and Pr103Blw had a different eclipse period of 5 min and 18 min respectively, and burst sizes of more than 100 PFU per infected cell. Ro103C3lw was specific to STEC O103 strains, whereas Pr103Blw had a broad host range lytic against STEC O103, O26, and Salmonella Javiana strains. Additionally, both phages rendered high efficiency of antimicrobial activities against STEC O103 strains. Most importantly, no lysogens were detected after the phage treatment. The findings of this study indicate that the lytic phage Ro103C3lw and Pr103Blw are promising antimicrobial agents that can be used for phage therapy of pathogenic E. coli O103 strains to improve food safety.