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Park DS, Park JH. Characteristics of Bacteriophage Isolates and Expression of Shiga Toxin Genes Transferred to Non Shiga Toxin-Producing E. coli by Transduction. J Microbiol Biotechnol 2021; 31:710-716. [PMID: 33782222 PMCID: PMC9705938 DOI: 10.4014/jmb.2102.02040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/24/2021] [Accepted: 03/24/2021] [Indexed: 12/15/2022]
Abstract
A risk analysis of Shiga toxin (Stx)-encoding bacteriophage was carried out by confirming the transduction phage to non-Stx-producing Escherichia coli (STEC) and subsequent expression of the Shiga toxin genes. The virulence factor stx1 was identified in five phages, and both stx1 and stx2 were found in four phages from a total of 19 phage isolates with seven non-O157 STEC strains. The four phages, designated as φNOEC41, φNOEC46, φNOEC47, and φNOEC49, belonged morphologically to the Myoviridae family. The stabilities of these phages to temperature, pH, ethanol, and NaClO were high with some variabilities among the phages. The infection of five non-STEC strains by nine Stx-encoding phages occurred at a rate of approximately 40%. Non-STEC strains were transduced by Stx-encoding phage to become lysogenic strains, and seven convertant strains had stx1 and/or stx2 genes. Only the stx1 gene was transferred to the receptor strains without any deletion. Gene expression of a convertant having both stx1 and stx2 genes was confirmed to be up to 32 times higher for Stx1 in 6% NaCl osmotic media and twice for Stx2 in 4% NaCl media, compared with expression in low-salt environments. Therefore, a new risk might arise from the transfer of pathogenic genes from Stx-encoding phages to otherwise harmless hosts. Without adequate sterilization of food exposed to various environments, there is a possibility that the toxicity of the phages might increase.
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Affiliation(s)
- Da-Som Park
- Department of Food Science and Biotechnology, College of BioNano Technology, Gachon University, Seongnam 13120, Republic of Korea
| | - Jong-Hyun Park
- Department of Food Science and Biotechnology, College of BioNano Technology, Gachon University, Seongnam 13120, Republic of Korea,Corresponding author Phone: +82-31-750-5523 Fax: +82-31-750-5283 E-mail:
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2
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Spilsberg B, Sekse C, Urdahl AM, Nesse LL, Johannessen GS. Persistence of a Stx-Encoding Bacteriophage in Minced Meat Investigated by Application of an Improved DNA Extraction Method and Digital Droplet PCR. Front Microbiol 2021; 11:581575. [PMID: 33552009 PMCID: PMC7855172 DOI: 10.3389/fmicb.2020.581575] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 12/01/2020] [Indexed: 12/01/2022] Open
Abstract
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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Affiliation(s)
- B Spilsberg
- Section for Molecular Biology, Norwegian Veterinary Institute, Oslo, Norway
| | - C Sekse
- Section for Molecular Biology, Norwegian Veterinary Institute, Oslo, Norway
| | - Anne M Urdahl
- Section for Food Safety and Animal Health Research, Norwegian Veterinary Institute, Oslo, Norway
| | - Live L Nesse
- Section for Food Safety and Animal Health Research, Norwegian Veterinary Institute, Oslo, Norway
| | - Gro S Johannessen
- Section for Food Safety and Animal Health Research, Norwegian Veterinary Institute, Oslo, Norway
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3
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Grygorcewicz B, Chajęcka‐Wierzchowska W, Augustyniak A, Wasak A, Stachurska X, Nawrotek P, Dołęgowska B. In‐milk inactivation of
Escherichia coli
O157:H7 by the environmental lytic bacteriophage ECPS‐6. J Food Saf 2020. [DOI: 10.1111/jfs.12747] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Bartłomiej Grygorcewicz
- Department of Microbiology, Immunology, and Laboratory MedicinePomeranian Medical University in Szczecin Szczecin Poland
| | | | - Adrian Augustyniak
- Building Materials and Construction ChemistryTechnische Universität Berlin Berlin Germany
| | - Agata Wasak
- Department of Immunology, Microbiology and Physiological ChemistryWest Pomeranian University of Technology Szczecin Poland
| | - Xymena Stachurska
- Department of Immunology, Microbiology and Physiological ChemistryWest Pomeranian University of Technology Szczecin Poland
| | - Paweł Nawrotek
- Department of Immunology, Microbiology and Physiological ChemistryWest Pomeranian University of Technology Szczecin Poland
| | - Barbara Dołęgowska
- Department of Microbiology, Immunology, and Laboratory MedicinePomeranian Medical University in Szczecin Szczecin Poland
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4
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Jończyk-Matysiak E, Łodej N, Kula D, Owczarek B, Orwat F, Międzybrodzki R, Neuberg J, Bagińska N, Weber-Dąbrowska B, Górski A. Factors determining phage stability/activity: challenges in practical phage application. Expert Rev Anti Infect Ther 2019; 17:583-606. [PMID: 31322022 DOI: 10.1080/14787210.2019.1646126] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Introduction: Phages consist of nucleic acids and proteins that may lose their activity under different physico-chemical conditions. The production process of phage formulations may decrease phage infectivity. Ingredients present in the preparation may influence phage particles, although preparation and storage conditions may also cause variations in phage titer. Significant factors are the manner of phage application, the patient's immune system status, the type of medication being taken, and diet. Areas covered: We discuss factors determining phage activity and stability, which is relevant for the preparation and application of phage formulations with the highest therapeutic efficacy. Our article should be helpful for more insightful implementation of clinical trials, which could pave the way for successful phage therapy. Expert opinion: The number of naturally occurring phages is practically unlimited and phages vary in their susceptibility to external factors. Modern methods offer engineering techniques which should lead to enhanced precision in phage delivery and anti-bacterial activity. Recent data suggesting that phages may also be used in treating nonbacterial infections as well as anti-inflammatory and immunomodulatory agents add further weight to such studies. It may be anticipated that different phage activities could have varying susceptibility to factors determining their actions.
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Affiliation(s)
- Ewa Jończyk-Matysiak
- a Bacteriophage Laboratory, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences , Wroclaw , Poland
| | - Norbert Łodej
- a Bacteriophage Laboratory, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences , Wroclaw , Poland
| | - Dominika Kula
- a Bacteriophage Laboratory, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences , Wroclaw , Poland
| | - Barbara Owczarek
- a Bacteriophage Laboratory, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences , Wroclaw , Poland
| | - Filip Orwat
- a Bacteriophage Laboratory, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences , Wroclaw , Poland
| | - Ryszard Międzybrodzki
- a Bacteriophage Laboratory, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences , Wroclaw , Poland.,b Department of Clinical Immunology, Transplantation Institute, Medical University of Warsaw , Warsaw , Poland.,c Phage Therapy Unit, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences , Wroclaw , Poland
| | - Joanna Neuberg
- a Bacteriophage Laboratory, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences , Wroclaw , Poland
| | - Natalia Bagińska
- a Bacteriophage Laboratory, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences , Wroclaw , Poland
| | - Beata Weber-Dąbrowska
- a Bacteriophage Laboratory, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences , Wroclaw , Poland.,c Phage Therapy Unit, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences , Wroclaw , Poland
| | - Andrzej Górski
- a Bacteriophage Laboratory, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences , Wroclaw , Poland.,b Department of Clinical Immunology, Transplantation Institute, Medical University of Warsaw , Warsaw , Poland.,c Phage Therapy Unit, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences , Wroclaw , Poland
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5
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Bacharouche J, Erdemli O, Rivet R, Doucouré B, Caillet C, Mutschler A, Lavalle P, Duval JFL, Gantzer C, Francius G. On the Infectivity of Bacteriophages in Polyelectrolyte Multilayer Films: Inhibition or Preservation of Their Bacteriolytic Activity? ACS APPLIED MATERIALS & INTERFACES 2018; 10:33545-33555. [PMID: 30192508 DOI: 10.1021/acsami.8b10424] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Antibiotic resistance in bacterial cells has motivated the scientific community to design new and efficient (bio)materials with targeted bacteriostatic and/or bactericide properties. In this work, a series of polyelectrolyte multilayer films differing in terms of polycation-polyanion combinations are constructed according to the layer-by-layer deposition method. Their capacities to host T4 and φx174 phage particles and maintain their infectivity and bacteriolytic activity are thoroughly examined. It is found that the macroscopic physicochemical properties of the films, which includes film thickness, swelling ratio, or mechanical stiffness (as derived by atomic force microscopy and spectroscopy measurements), do not predominantly control the selectivity of the films for hosting infective phages. Instead, it is evidenced that the intimate electrostatic interactions locally operational between the loaded phages and the polycationic and polyanionic PEM components may lead to phage activity reduction and preservation/enhancement, respectively. It is argued that the underlying mechanism involves the screening of the phage capsid receptors (operational in cell recognition/infection processes) because of the formation of either polymer-phage hetero-assemblies or polymer coating surrounding the bioactive phage surface.
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Affiliation(s)
- Jalal Bacharouche
- Université de Lorraine, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME, UMR 7564 , Villers-lès-Nancy F-54600 , France
- CNRS, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME, UMR 7564 , Villers-lès-Nancy F-54600 , France
| | - Ozge Erdemli
- CNRS, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME, UMR 7564 , Villers-lès-Nancy F-54600 , France
- Institut National de la Santé et de la Recherche Médicale, INSERM Unité 1121 , 11 rue Humann , 67085 Strasbourg Cedex , France
- Université de Strasbourg , Faculté de Chirurgie Dentaire , 8 rue Sainte Elisabeth , 67000 Strasbourg , France
| | - Romain Rivet
- Université de Lorraine, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME, UMR 7564 , Villers-lès-Nancy F-54600 , France
- CNRS, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME, UMR 7564 , Villers-lès-Nancy F-54600 , France
| | - Balla Doucouré
- Université de Lorraine, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME, UMR 7564 , Villers-lès-Nancy F-54600 , France
- CNRS, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME, UMR 7564 , Villers-lès-Nancy F-54600 , France
| | - Céline Caillet
- Université de Lorraine, Laboratoire Interdisciplinaire des Environnements Continentaux, UMR 7360 , 54501 Vandœuvre-lès-Nancy , France
- CNRS, Laboratoire Interdisciplinaire des Environnements Continentaux, UMR 7360 , 54501 Vandœuvre-lès-Nancy , France
| | - Angela Mutschler
- Institut National de la Santé et de la Recherche Médicale, INSERM Unité 1121 , 11 rue Humann , 67085 Strasbourg Cedex , France
- Université de Strasbourg , Faculté de Chirurgie Dentaire , 8 rue Sainte Elisabeth , 67000 Strasbourg , France
| | - Philippe Lavalle
- Institut National de la Santé et de la Recherche Médicale, INSERM Unité 1121 , 11 rue Humann , 67085 Strasbourg Cedex , France
- Université de Strasbourg , Faculté de Chirurgie Dentaire , 8 rue Sainte Elisabeth , 67000 Strasbourg , France
| | - Jérôme F L Duval
- Université de Lorraine, Laboratoire Interdisciplinaire des Environnements Continentaux, UMR 7360 , 54501 Vandœuvre-lès-Nancy , France
- CNRS, Laboratoire Interdisciplinaire des Environnements Continentaux, UMR 7360 , 54501 Vandœuvre-lès-Nancy , France
| | - Christophe Gantzer
- Université de Lorraine, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME, UMR 7564 , Villers-lès-Nancy F-54600 , France
- CNRS, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME, UMR 7564 , Villers-lès-Nancy F-54600 , France
| | - Grégory Francius
- Université de Lorraine, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME, UMR 7564 , Villers-lès-Nancy F-54600 , France
- CNRS, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME, UMR 7564 , Villers-lès-Nancy F-54600 , France
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6
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Milho C, Silva MD, Melo L, Santos S, Azeredo J, Sillankorva S. Control of Salmonella Enteritidis on food contact surfaces with bacteriophage PVP-SE2. BIOFOULING 2018; 34:753-768. [PMID: 30270665 DOI: 10.1080/08927014.2018.1501475] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 07/06/2018] [Accepted: 07/09/2018] [Indexed: 06/08/2023]
Abstract
Salmonella is one of the worldwide leading foodborne pathogens responsible for illnesses and hospitalizations, and its capacity to form biofilms is one of its many virulence factors. This work evaluated (bacterio)phage control of adhered and biofilm cells of Salmonella Enteritidis on three different substrata at refrigerated and room temperatures, and also a preventive approach in poultry skin. PVP-SE2 phage was efficient in reducing both 24- and 48-h old Salmonella biofilms from polystyrene and stainless steel causing 2 to 5 log CFU cm-2 reductions with a higher killing efficiency at room temperature. PVP-SE2 phage application on poultry skins reduced levels of Salmonella. Freezing phage-pretreated poultry skin samples had no influence on the viability of phage PVP-SE2 and their in vitro contamination with S. Enteritidis provided evidence that phages prevented their further growth. Although not all conditions favor phage treatment, this study endorses their use to prevent and control foodborne pathogen colonization of surfaces.
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Affiliation(s)
- Catarina Milho
- a Centre of Biological Engineering , LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho , Braga , Portugal
| | - Maria Daniela Silva
- a Centre of Biological Engineering , LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho , Braga , Portugal
| | - Luís Melo
- a Centre of Biological Engineering , LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho , Braga , Portugal
| | - Sílvio Santos
- a Centre of Biological Engineering , LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho , Braga , Portugal
| | - Joana Azeredo
- a Centre of Biological Engineering , LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho , Braga , Portugal
| | - Sanna Sillankorva
- a Centre of Biological Engineering , LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho , Braga , Portugal
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7
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Bacteriophage cocktail for biocontrol of Escherichia coli O157:H7: Stability and potential allergenicity study. PLoS One 2018; 13:e0195023. [PMID: 29763937 PMCID: PMC5953568 DOI: 10.1371/journal.pone.0195023] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 03/15/2018] [Indexed: 12/18/2022] Open
Abstract
Escherichia coli O157:H7 has become a global public health and a food safety problem. Despite the implementation of control strategies that guarantee the safety in various products, outbreaks persist and new alternatives are necessary to reduce this pathogen along the food chain. Recently, our group isolated and characterised lytic bacteriophages against E. coli O157:H7 with potential to be used as biocontrol agents in food. To this end, phages need certain requirements to allow their manufacture and application. The aim of this study was to determine the physical stability and allergenic potential of free and microencapsulated (ME) bacteriophage cocktails against E. coli O157:H7. In vitro and in vivo studies were performed to determine phage survival under different pH, gastrointestinal conditions, temperature and UV light intensities. Results showed that the stability of ME phages was significantly (P<0.05) higher than free phages after ultraviolet irradiation, pH conditions between 3 to 7, and exposure to temperatures between at -80°C and 70°C. Both formulations were highly sensitive to very low pH in simulated gastric fluid, but stable in bile salts. In vivo studies in mice confirmed these phages passed through the gastrointestinal tract and were excreted in faeces. In silico, full-length alignment analysis showed that all phage proteins were negative for allergenic potential, but different predicting criteria classified seven phage proteins with a very low probability to be an allergen. In conclusion, these data demonstrated that microencapsulation provided a greater stability to phage formulation under stress conditions and assure a more suitable commercial formulation for the biological control of E. coli O157:H7.
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8
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Nyambe S, Burgess C, Whyte P, Bolton D. An investigation of vtx 2 bacteriophage transduction to different Escherichia coli patho-groups in food matrices and nutrient broth. Food Microbiol 2017; 68:1-6. [PMID: 28800816 DOI: 10.1016/j.fm.2017.06.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 05/19/2017] [Accepted: 06/04/2017] [Indexed: 12/14/2022]
Abstract
This study investigated bacteriophage (phage) mediated transfer of the vtx2 gene from a donor Escherichia coli (C600φ3538(Δvtx2::cat)) to enteropathogenic (EPEC), enterotoxigenic (ETEC), enteroaggregative (EAEC), enteroinvasive (EIEC) and diffusely adherent (DAEC) E. coli strains in LB broth, milk, ground beef and lettuce. Two bacterial concentrations for both the E. coli donor and recipient strains, 3 and 5 log10 CFU/ml (LB broth and milk)/g (beef) or/cm2 (lettuce), were used. When transductants were obtained, the location of insertion of the phage (insertion sites wrbA, yehA, sbcB, yecE and/or Z2577) in the E. coli chromosome was investigated by PCR. The vtx2 gene was readily transferred to EAEC O104:H4 (E99518) in all matrices and inserted into the chromosome at the sbcB locus. At higher cell concentrations, transductants were also obtained with ETEC E4683, ETEC E8057 (insertion site unknown) and DAEC O75:H- E66438 (insertion site unknown) in LB broth and milk. It was concluded that the vtx2 gene may be transferred by bacteriophage to different E. coli pathotypes in laboratory and food matrices, resulting in the spread of the vtx2 gene and the emergence of novel foodborne pathogens.
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Affiliation(s)
- Sepo Nyambe
- Food Safety Department, Teagasc Food Research Centre, Ashtown, Dublin 15, Ireland; School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland
| | - Catherine Burgess
- Food Safety Department, Teagasc Food Research Centre, Ashtown, Dublin 15, Ireland
| | - Paul Whyte
- School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland
| | - Declan Bolton
- Food Safety Department, Teagasc Food Research Centre, Ashtown, Dublin 15, Ireland.
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9
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Tomat D, Balagué C, Aquili V, Verdini R, Quiberoni A. Resistance of phages lytic to pathogenicEscherichia colito sanitisers used by the food industry and in home settings. Int J Food Sci Technol 2017. [DOI: 10.1111/ijfs.13626] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- David Tomat
- Facultad de Ciencias Bioquímicas y Farmacéuticas; Área de Bacteriología; Universidad Nacional de Rosario; Suipacha 531 S2002LRK Rosario Argentina
| | - Claudia Balagué
- Facultad de Ciencias Bioquímicas y Farmacéuticas; Área de Bacteriología; Universidad Nacional de Rosario; Suipacha 531 S2002LRK Rosario Argentina
| | - Virginia Aquili
- Facultad de Ciencias Bioquímicas y Farmacéuticas; Área de Bacteriología; Universidad Nacional de Rosario; Suipacha 531 S2002LRK Rosario Argentina
| | - Roxana Verdini
- Instituto de Química Rosario (UNR - CONICET); Suipacha 570 2000 Rosario, Santa Fe Argentina
| | - Andrea Quiberoni
- Facultad de Ingeniería Química; Instituto de Lactología Industrial (UNL - CONICET); Santiago del Estero 2829 3000 Santa Fe Argentina
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10
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Induction of Shiga Toxin-Encoding Prophage by Abiotic Environmental Stress in Food. Appl Environ Microbiol 2017; 83:AEM.01378-17. [PMID: 28778890 DOI: 10.1128/aem.01378-17] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 07/24/2017] [Indexed: 11/20/2022] Open
Abstract
The prophage-encoded Shiga toxin is a major virulence factor in Stx-producing Escherichia coli (STEC). Toxin production and phage production are linked and occur after induction of the RecA-dependent SOS response. However, food-related stress and Stx-prophage induction have not been studied at the single-cell level. This study investigated the effects of abiotic environmental stress on stx expression by single-cell quantification of gene expression in STEC O104:H4 Δstx2::gfp::ampr In addition, the effect of stress on production of phage particles was determined. The lethality of stressors, including heat, HCl, lactic acid, hydrogen peroxide, and high hydrostatic pressure, was selected to reduce cell counts by 1 to 2 log CFU/ml. The integrity of the bacterial membrane after exposure to stress was measured by propidium iodide (PI). The fluorescent signals of green fluorescent protein (GFP) and PI were quantified by flow cytometry. The mechanism of prophage induction by stress was evaluated by relative gene expression of recA and cell morphology. Acid (pH < 3.5) and H2O2 (2.5 mM) induced the expression of stx2 in about 18% and 3% of the population, respectively. The mechanism of prophage induction by acid differs from that of induction by H2O2 H2O2 induction but not acid induction corresponded to production of infectious phage particles, upregulation of recA, and cell filamentation. Pressure (200 MPa) or heat did not induce the Stx2-encoding prophage (Stx2-prophage). Overall, the quantification method developed in this study allowed investigation of prophage induction and physiological properties at the single-cell level. H2O2 and acids mediate different pathways to induce Stx2-prophage.IMPORTANCE Induction of the Stx-prophage in STEC results in production of phage particles and Stx and thus relates to virulence as well as the transduction of virulence genes. This study developed a method for a detection of the induction of Stx-prophages at the single-cell level; membrane permeability and an indication of SOS response to environmental stress were additionally assessed. H2O2 and mitomycin C induced expression of the prophage and activated a SOS response. In contrast, HCl and lactic acid induced the Stx-prophage but not the SOS response. The lifestyle of STEC exposes the organism to intestinal and extraintestinal environments that impose oxidative and acid stress. A more thorough understanding of the influence of food processing-related stressors on Stx-prophage expression thus facilitates control of STEC in food systems by minimizing prophage induction during food production and storage.
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11
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Nyambe S, Burgess C, Whyte P, Bolton D. The Survival of a Temperate vtx Bacteriophage and an Anti-Verocytotoxigenic Escherichia coli O157 Lytic Phage in Water and Soil Samples. Zoonoses Public Health 2016; 63:632-640. [PMID: 27334728 DOI: 10.1111/zph.12278] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Indexed: 11/28/2022]
Abstract
Verocytotoxigenic (vtx) Escherichia coli (VTEC) are zoonotic foodborne pathogens with the vtx operon encoded by lambdoid bacteriophage (phage). Despite much research on the host bacteria, similar data on the persistence of verocytotoxin converting phage and the ecological niches where transduction occurs are lacking and novel VTEC of important public health significance, have and continue to emerge. This study investigated the survival of a temperate vtx bacteriophage (24B ::kanamycinR ) in water (raw farm, pasteurized farm, laboratory tap and autoclaved purified water) and soil (sandy loam and loam soil). It also examined the persistence of an anti-VTEC lytic phage (e11/2) in the same matrices as this may be one option for controlling the emergence of novel VTEC, especially in farm ecological niches where other control options, such as chemical, heat or high pressure treatments, are not feasible. Samples inoculated with 24B ::kanamycinR and e11/2 bacteriophage (8 log10 pfu/ml or pfu/g) separately were incubated at 4°C and 14°C, representative Irish Winter and Summer temperatures, respectively, and tested every 2 days for 40 days. The transduction of 24B ::kanamycinR was also continuously assessed. Both phages survived with reductions observed, regardless of matrix or storage temperature. Moreover, 24B ::kanamycinR was able to transduce its host E. coli strain. It was therefore concluded that aquatic and soil environments on farms may serve as a vtx phage reservoir and transduction point but anti-VTEC phage is a possible biocontrol option.
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Affiliation(s)
- S Nyambe
- Food Safety Department, Teagasc Food Research Centre, Ashtown, Dublin, Ireland.,School of Veterinary Medicine, University College Dublin, Belfield, Dublin, Ireland
| | - C Burgess
- Food Safety Department, Teagasc Food Research Centre, Ashtown, Dublin, Ireland
| | - P Whyte
- School of Veterinary Medicine, University College Dublin, Belfield, Dublin, Ireland
| | - D Bolton
- Food Safety Department, Teagasc Food Research Centre, Ashtown, Dublin, Ireland
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Lenzi LJ, Lucchesi PMA, Medico L, Burgán J, Krüger A. Effect of the Food Additives Sodium Citrate and Disodium Phosphate on Shiga Toxin-Producing Escherichia coli and Production of stx-Phages and Shiga toxin. Front Microbiol 2016; 7:992. [PMID: 27446032 PMCID: PMC4917541 DOI: 10.3389/fmicb.2016.00992] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 06/09/2016] [Indexed: 11/16/2022] Open
Abstract
Induction and propagation of bacteriophages along the food production chain can represent a significant risk when bacteriophages carry genes for potent toxins. The aim of this study was to evaluate the effect of different compounds used in the food industry on the growth of Shiga toxin-producing Escherichia coli (STEC) and the production of stx-phage particles and Shiga toxin. We tested the in vitro effect of lactic acid, acetic acid, citric acid, disodium phosphate, and sodium citrate on STEC growth. A bacteriostatic effect was observed in most of treated cultures. The exceptions were those treated with sodium citrate and disodium phosphate in which similar growth curves to the untreated control were observed, but with reduced OD600 values. Evaluation of phage production by plaque-based assays showed that cultures treated with sodium citrate and disodium phosphate released phages in similar o lower levels than untreated cultures. However, semi-quantification of Stx revealed higher levels of extracellular Stx in STEC cultures treated with 2.5% sodium citrate than in untreated cultures. Our results reinforce the importance to evaluate if additives and other treatments used to decrease bacterial contamination in food induce stx-phage and Stx production.
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Affiliation(s)
- Lucas J Lenzi
- Laboratorio de Inmunoquímica y Biotecnología, Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires, Tandil Argentina
| | - Paula M A Lucchesi
- Laboratorio de Inmunoquímica y Biotecnología, Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires, TandilArgentina; Centro de Investigación Veterinaria de Tandil, CONICET-CIC-UNCPBA, TandilArgentina
| | - Lucía Medico
- Laboratorio de Inmunoquímica y Biotecnología, Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires, Tandil Argentina
| | - Julia Burgán
- Laboratorio de Inmunoquímica y Biotecnología, Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires, TandilArgentina; Centro de Investigación Veterinaria de Tandil, CONICET-CIC-UNCPBA, TandilArgentina
| | - Alejandra Krüger
- Laboratorio de Inmunoquímica y Biotecnología, Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires, TandilArgentina; Centro de Investigación Veterinaria de Tandil, CONICET-CIC-UNCPBA, TandilArgentina
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14
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Characterization and application of phages isolated from sewage for reduction of Escherichia coli O157:H7 in biofilm. Lebensm Wiss Technol 2015. [DOI: 10.1016/j.lwt.2014.09.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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15
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Improving detection of Shiga toxin-producing Escherichia coli by molecular methods by reducing the interference of free Shiga toxin-encoding bacteriophages. Appl Environ Microbiol 2014; 81:415-21. [PMID: 25362055 DOI: 10.1128/aem.02941-14] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Detection of Shiga toxin-producing Escherichia coli (STEC) by culture methods is advisable to identify the pathogen, but recovery of the strain responsible for the disease is not always possible. The use of DNA-based methods (PCR, quantitative PCR [qPCR], or genomics) targeting virulence genes offers fast and robust alternatives. However, detection of stx is not always indicative of STEC because stx can be located in the genome of temperate phages found in the samples as free particles; this could explain the numerous reports of positive stx detection without successful STEC isolation. An approach based on filtration through low-protein-binding membranes and additional washing steps was applied to reduce free Stx phages without reducing detection of STEC bacteria. River water, food, and stool samples were spiked with suspensions of phage 933W and, as a STEC surrogate, a lysogen harboring a recombinant Stx phage in which stx was replaced by gfp. Bacteria were tested either by culture or by qPCR for gfp while phages were tested using qPCR targeting stx in phage DNA. The procedure reduces phage particles by 3.3 log10 units without affecting the recovery of the STEC population (culturable or assessed by qPCR). The method is applicable regardless of phage and bacteria densities and is useful in different matrices (liquid or solid). This approach eliminates or considerably reduces the interference of Stx phages in the detection of STEC by molecular methods. The reduction of possible interference would increase the efficiency and reliability of genomics for STEC detection when the method is applied routinely in diagnosis and food analysis.
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Martínez-Castillo A, Muniesa M. Implications of free Shiga toxin-converting bacteriophages occurring outside bacteria for the evolution and the detection of Shiga toxin-producing Escherichia coli. Front Cell Infect Microbiol 2014; 4:46. [PMID: 24795866 PMCID: PMC3997033 DOI: 10.3389/fcimb.2014.00046] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 03/27/2014] [Indexed: 11/13/2022] Open
Abstract
In this review we highlight recent work that has increased our understanding of the distribution of Shiga toxin-converting phages that can be detected as free phage particles, independently of Shiga toxin-producing bacteria (STEC). Stx phages are a quite diverse group of temperate phages that can be found in their prophage state inserted within the STEC chromosome, but can also be found as phages released from the cell after activation of their lytic cycle. They have been detected in extraintestinal environments such as water polluted with feces from humans or animals, food samples or even in stool samples of healthy individuals. The high persistence of phages to several inactivation conditions makes them suitable candidates for the successful mobilization of stx genes, possibly resulting in the genes reaching a new bacterial genomic background by means of transduction, where ultimately they may be expressed, leading to Stx production. Besides the obvious fact that Stx phages circulating between bacteria can be, and probably are, involved in the emergence of new STEC strains, we review here other possible ways in which free Stx phages could interfere with the detection of STEC in a given sample by current laboratory methods and how to avoid such interference.
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Affiliation(s)
| | - Maite Muniesa
- Department of Microbiology, Faculty of Biology, University of BarcelonaBarcelona, Spain
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17
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Persistence of infectious Shiga toxin-encoding bacteriophages after disinfection treatments. Appl Environ Microbiol 2014; 80:2142-9. [PMID: 24463973 DOI: 10.1128/aem.04006-13] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
In Shiga toxin-producing Escherichia coli (STEC), induction of Shiga toxin-encoding bacteriophages (Stx phages) causes the release of free phages that can later be found in the environment. The ability of Stx phages to survive different inactivation conditions determines their prevalence in the environment, the risk of stx transduction, and the generation of new STEC strains. We evaluated the infectivity and genomes of two Stx phages (Φ534 and Φ557) under different conditions. Infectious Stx phages were stable at 4, 22, and 37°C and at pH 7 and 9 after 1 month of storage but were completely inactivated at pH 3. Infective Stx phages decreased moderately when treated with UV (2.2-log10 reduction for an estimated UV dose of 178.2 mJ/cm(2)) or after treatment at 60 and 68°C for 60 min (2.2- and 2.5-log10 reductions, respectively) and were highly inactivated (3 log10) by 10 ppm of chlorine in 1 min. Assays in a mesocosm showed lower inactivation of all microorganisms in winter than in summer. The number of Stx phage genomes did not decrease significantly in most cases, and STEC inactivation was higher than phage inactivation under all conditions. Moreover, Stx phages retained the ability to lysogenize E. coli after some of the treatments.
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18
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Lee YD, Kim JY, Park JH. Characteristics of coliphage ECP4 and potential use as a sanitizing agent for biocontrol of Escherichia coli O157:H7. Food Control 2013. [DOI: 10.1016/j.foodcont.2013.04.043] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Langsrud S, Heir E, Rode TM. Survival of Shiga toxin-producing Escherichia coli and Stx bacteriophages in moisture enhanced beef. Meat Sci 2013; 97:339-46. [PMID: 24134920 DOI: 10.1016/j.meatsci.2013.09.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 09/13/2013] [Accepted: 09/24/2013] [Indexed: 10/26/2022]
Abstract
Moisture enhancement of meat through injection is a technology to improve the sensory properties and the weight of meat. However, the technology may increase the risk of food borne infections. Shiga toxin-producing Escherichia coli (STEC) or bacteriophages carrying cytotoxin genes (Shiga toxin genes, stx), which is normally only present on the surface of intact beef, may be transferred to the inner parts of the muscle during the injection process. Pathogens and bacteriophages surviving the storage period may not be eliminated in the cooking process since many consumers prefer undercooked beef. Measures to increase the microbial food safety of moisture enhanced beef may include sterilization or washing of the outer surface of the meat before injection, avoiding recycling of marinade and addition of antimicrobial agents to the marinade. This paper reviews the literature regarding microbial safety of moisture enhanced beef with special emphasis on STEC and Stx bacteriophages. Also, results from a European Union research project, ProSafeBeef (Food-CT-16 2006-36241) are presented.
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Affiliation(s)
- Solveig Langsrud
- Nofima, Norwegian Institute of Food, Fishery and Aquaculture, P.O. Box 210, N-1431 Ås, Norway
| | - Even Heir
- Nofima, Norwegian Institute of Food, Fishery and Aquaculture, P.O. Box 210, N-1431 Ås, Norway
| | - Tone Mari Rode
- Nofima, Norwegian Institute of Food, Fishery and Aquaculture, P.O. Box 210, N-1431 Ås, Norway
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SARTIKA DEWI, BUDIARTI SRI, SUDARWANTO MIRNAWATI. Phage FR38 Treatment on Sprague Dawley Rat Inferred from Blood Parameters and Organ Systems. HAYATI JOURNAL OF BIOSCIENCES 2012. [DOI: 10.4308/hjb.19.3.131] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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