Characterization of a Lytic Bacteriophage as an Antimicrobial Agent for Biocontrol of Shiga Toxin-Producing Escherichia coli O145 Strains

Abstract

Shiga toxin-producing Escherichia coli (STEC) O145 is one of the most prevalent non-O157 serogroups associated with foodborne outbreaks. Lytic phages are a potential alternative to antibiotics in combatting bacterial pathogens. In this study, we characterized a Siphoviridae phage lytic against STEC O145 strains as a novel antimicrobial agent. Escherichia phage vB_EcoS-Ro145clw (Ro145clw) was isolated and purified prior to physiological and genomic characterization. Then, in vitro antimicrobial activity against an outbreak strain, E. coli O145:H28, was evaluated. Ro145clw is a double-stranded DNA phage with a genome 42,031 bp in length. Of the 67 genes identified in the genome, 21 were annotated with functional proteins, none of which were stx genes. Ro145clw had a latent period of 21 min and a burst size of 192 phages per infected cell. The phage could sustain a wide range of pH (pH 3 to pH 10) and temperatures (−80 °C to −73 °C). Ro145clw was able to reduce E. coli O145:H28 in lysogeny broth by approximately 5 log at 37 °C in four hours. These findings indicate that the Ro145clw phage is a promising antimicrobial agent that can be used to control E. coli O145 in adverse pH and temperature conditions.

Gida Kaynakli Patojen Escherichia Coli O157:h7’ye Karşi Etki̇li̇ Bakteri̇yofajlar

“…Ibrahim (1969) reported that E. coli phages were also effective against some Salmonella serovars. Liao et al (2019) (Necel et al, 2020). Chang and Kim (2011) Results from the present study are similar to these studies, revealing that some isolated phages are infective against E. coli O157:H7 strains with high target specificity and some isolated phages are infective against other E. coli strains and some Salmonella enterica serovars in addition to E. coli O157:H7 strains.…”

Characterization of Two New Shiga Toxin-Producing Escherichia coli O103-Infecting Phages Isolated from an Organic Farm

“…During the incubation, 1 mL of sample was collected at a 2 min interval for phage Ro103C3lw (for a total of 20 min) and a 5 min interval for phage Pr103Blw (for a total of 55 min). The sample from each time point was flited through a sterile 0.22-μm membrane filter for double-layer plaque assay to determine phage latent periods using the similar protocol, as described previously [ 35 ]. The plates were incubated at 37 °C for 24 h. The one-step growth curve experiment of each phage was performed three times.…”

“…Two research groups isolated phages phiC119 and AKFV33, both targeted specifically against STEC O157 strains, were evaluated their biocontrol potential, including host range and lysis time, and identified the presence of harmful genes [ 33 , 34 ]. We previously isolated and characterized a lytic bacteriophage vB_EcoS-Ro145clw with antimicrobial activity against STEC O145 and E. coli O145:H28 outbreak strains [ 35 ]. We also investigated genomic characteristics of the phage contributing to phage stability and antimicrobial activity for a broad phage application in various environments.…”

Evaluation of a Potential Bacteriophage Cocktail for the Control of Shiga-Toxin Producing Escherichia coli in Food

“…According to literature, the principal efforts of using bacteriophages against STEC strains have been directed mainly toward serogroup O157 (O'Flynn et al, 2004;Abuladze et al, 2008;Sharma et al, 2009;Viazis et al, 2011;Hudson et al, 2015;Snyder et al, 2016). However, given the increase in the finding of non-O157 in food, different authors have focused their efforts also toward other serogroups (Tomat et al, 2013;Tolen et al, 2018;Liao et al, 2019).…”