An investigation of vtx2 bacteriophage transduction to different Escherichia coli patho-groups in food matrices and nutrient broth

Nyambe, Sepo; Burgess, Catherine M.; Whyte, Paul; Bolton, Declan

doi:10.1016/j.fm.2017.06.004

Cited by 5 publications

(3 citation statements)

References 38 publications

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“…Shiga toxin containing prophages can convert the host strain since they integrate their genome using specific gene insertion sites. In these three transduced strains, the encoded gene present was the unknown function yecE, which is consistent with results from Nyambe et al 45,46 . A previous study indicated that the genetic diversity of the integrase-encoding genes among various www.nature.com/scientificreports/ Stx prophages is related to the different insertion sites of these prophages within the bacterial chromosome 47 .…”

Section: Discussionsupporting

confidence: 91%

Impact of Shiga-toxin encoding gene transduction from O80:H2 Shiga toxigenic Escherichia coli (STEC) on non-STEC strains

Habets

Antoine

Wagemans

et al. 2022

Sci Rep

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Shiga toxin-producing Escherichia coli (STEC) are major foodborne pathogens that cause human diseases ranging from diarrhea to life-threatening complications including hemolytic–uremic syndrome. Virulence of STEC strains and their ability to cause severe diseases are associated with the activity of prophage-encoded Shiga toxins (Stxs). The first objective of this work was to isolate and characterize the Stx2d phage from STEC O80:H2 and to study the transfer of this phage in non-STEC strains. The second objective was to assess the survival of Galleria mellonella larvae inoculated with these transduced strains. Firstly, one bacteriophage isolated from a STEC O80:H2 strain was used to infect six non-STEC strains, resulting in the conversion of three strains. Then, stability assays were performed, showing that this phage was stable in the new STEC strains after three successive subculturing steps, as confirmed by a combination of short and long read genome sequencing approaches. This phage, vB_EcoS_ULI-O80_Stx2d, is resistant to moderate temperature and pH. It belongs to a currently unclassified genus and family within the Caudoviricetes class, shares 98% identity with Stx2_112808 phage and encodes several proteins involved in the lysogenic cycle. The yecE gene was identified at the insertion site. Finally, G. mellonella experiments showed that the transduced strains caused significantly higher mortality rates than the corresponding non-STEC strains. In conclusion, this study showed that stx2d gene from O80:H2 E. coli can be transferred to non-STEC strains and contributes to their virulence.

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Section: Discussionsupporting

confidence: 91%

Impact of Shiga-toxin encoding gene transduction from O80:H2 Shiga toxigenic Escherichia coli (STEC) on non-STEC strains

Habets

Antoine

Wagemans

et al. 2022

Sci Rep

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“…However, a study examining the ability of various stx2-phages to infect E. coli from different pathotypes found that while all strains could be infected with Stx-phages, not all Stx-phages infected every E. coli and phage integration was rarely stable [40]. Other studies examining Stx-phage infection on various food sources found that for Stx-phage infection to occur both the donor and recipient need to be present in high concentrations not typically found in food samples [41,42]. Together, these studies suggest that while Stx-phage infection is possible: (1) It is unlikely to occur and (2) rarely is phage integration stable.…”

Section: Discussionmentioning

confidence: 99%

Competition among Escherichia coli Strains for Space and Resources

Paquette

Zaheer

Stanford

et al. 2018

Veterinary Sciences

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Shiga toxin-producing Escherichia coli (STEC) are a subgroup of E. coli causing human diseases. Methods to control STEC in livestock and humans are limited. These and other emerging pathogens are a global concern and novel mitigation strategies are required. Habitats populated by bacteria are subjected to competition pressures due to limited space and resources but they use various strategies to compete in natural environments. Our objective was to evaluate non-pathogenic E. coli strains isolated from cattle feces for their ability to out-compete STEC. Competitive fitness of non-pathogenic E. coli against STEC were assessed in competitions using liquid, agar, and nutrient limiting assays. Winners were determined by enumeration using O-serogroup specific quantitative PCR or a semi-quantitative grading. Initial liquid competitions identified two strong non-pathogenic competitors (O103F and O26E) capable of eliminating various STEC including O157 and O111. The strain O103F was dominant across permeable physical barriers for all tested E. coli and STEC strains indicating the diffusion of antimicrobial molecules. In direct contact and even with temporal disadvantages, O103F out-competed STEC O157E. The results suggest that O103F or the diffusible molecule(s) it produces have a potential to be used as an alternative STEC mitigation strategy, either in medicine or the food industry.

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“…In the compost model, however, described by Johannessen et al (2005), both E. coli and the labeled Stx phage were effectively removed after being exposed to a temperature of >60 • C for at least 5 days. Nyambe et al (2017) studied transduction of a Stx2 phage to different E. coli pathotypes in broth and different food matrices at an optimum growth temperature of 37 • C of both donor and recipient. The results indicated that the Stx2 phage used could be transferred to different pathotypes of E. coli in food matrices.…”

Section: Introductionmentioning

confidence: 99%

Persistence of a Stx-Encoding Bacteriophage in Minced Meat Investigated by Application of an Improved DNA Extraction Method and Digital Droplet PCR

et al. 2021

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Shiga toxin-producing Escherichia coli (STEC) are important food-borne pathogens with Shiga toxins as the main virulence factor. Shiga toxins are encoded on Shiga toxin-encoding bacteriophages (Stx phages). Stx phages may exist as free bacteriophages in the environment or in foods or as prophages integrated into the host genome. From a food safety perspective, it is important to have knowledge on the survival and persistence of Stx phages in food products since these may integrate into the bacterial hosts through transduction if conditions are right. Here, we present the results from a study investigating the survival of a Stx phage in minced meat from beef stored at a suboptimal temperature (8°C) for food storage along with modifications and optimizations of the methods applied. Minced meat from beef was inoculated with known levels of a labeled Stx phage prior to storage. Phage filtrates were used for plaque assays and DNA extraction, followed by real-time PCR and digital droplet PCR (ddPCR). The results from the pilot study suggested that the initial DNA extraction protocol was not optimal, and several modifications were tested before a final protocol was defined. The final DNA extraction protocol comprised ultra-centrifugation of the entire phage filtrate for concentrating phages and two times phenol–chloroform extraction. The protocol was used for two spiking experiments. The DNA extraction protocol resulted in flexibility in the amount of DNA available for use in PCR analyses, ultimately increasing the sensitivity of the method used for quantification of phages in a sample. All three quantification methods employed (i.e., plaque assays, real-time PCR, and ddPCR) showed similar trends in the development of the phages during storage, where ddPCR has the benefit of giving absolute quantification of DNA copies in a simple experimental setup. The results indicate that the Stx phages persist and remain infective for at least 20 days under the storage conditions used in the present study. Stx phages in foods might represent a potential risk for humans. Although it can be speculated that transduction may take place at 8°C with subsequent forming of STEC, it can be expected to be a rare event. However, such an event may possibly take place under more optimal conditions, such as an increase in storage temperature of foods or in the gastrointestinal tract of humans.

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An investigation of vtx2 bacteriophage transduction to different Escherichia coli patho-groups in food matrices and nutrient broth

Cited by 5 publications

References 38 publications

Impact of Shiga-toxin encoding gene transduction from O80:H2 Shiga toxigenic Escherichia coli (STEC) on non-STEC strains

Impact of Shiga-toxin encoding gene transduction from O80:H2 Shiga toxigenic Escherichia coli (STEC) on non-STEC strains

Competition among Escherichia coli Strains for Space and Resources

Persistence of a Stx-Encoding Bacteriophage in Minced Meat Investigated by Application of an Improved DNA Extraction Method and Digital Droplet PCR

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