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A Validation System for Selection of Bacteriophages against Shiga Toxin-Producing Escherichia coli Contamination

Shiga toxin-producing Escherichia coli (STEC) can cause severe infections in humans, leading to serious diseases and dangerous complications, such as hemolytic-uremic syndrome. Although cattle are a major reservoir of STEC, the most commonly occurring source of human infections are food products (e....

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Autores principales: Necel, Agnieszka, Bloch, Sylwia, Nejman-Faleńczyk, Bożena, Dydecka, Aleksandra, Topka-Bielecka, Gracja, Węgrzyn, Alicja, Węgrzyn, Grzegorz
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8470416/
https://www.ncbi.nlm.nih.gov/pubmed/34564648
http://dx.doi.org/10.3390/toxins13090644
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author Necel, Agnieszka
Bloch, Sylwia
Nejman-Faleńczyk, Bożena
Dydecka, Aleksandra
Topka-Bielecka, Gracja
Węgrzyn, Alicja
Węgrzyn, Grzegorz
author_facet Necel, Agnieszka
Bloch, Sylwia
Nejman-Faleńczyk, Bożena
Dydecka, Aleksandra
Topka-Bielecka, Gracja
Węgrzyn, Alicja
Węgrzyn, Grzegorz
author_sort Necel, Agnieszka
collection PubMed
description Shiga toxin-producing Escherichia coli (STEC) can cause severe infections in humans, leading to serious diseases and dangerous complications, such as hemolytic-uremic syndrome. Although cattle are a major reservoir of STEC, the most commonly occurring source of human infections are food products (e.g., vegetables) contaminated with cow feces (often due to the use of natural fertilizers in agriculture). Since the use of antibiotics against STEC is controversial, other methods for protection of food against contaminations by these bacteria are required. Here, we propose a validation system for selection of bacteriophages against STEC contamination. As a model system, we have employed a STEC-specific bacteriophage vB_Eco4M-7 and the E. coli O157:H7 strain no. 86-24, bearing Shiga toxin-converting prophage ST2-8624 (Δstx2::cat gfp). When these bacteria were administered on the surface of sliced cucumber (as a model vegetable), significant decrease in number viable E. coli cells was observed after 6 h of incubation. No toxicity of vB_Eco4M-7 against mammalian cells (using the Balb/3T3 cell line as a model) was detected. A rapid decrease of optical density of STEC culture was demonstrated following addition of a vB_Eco4M-7 lysate. However, longer incubation of susceptible bacteria with this bacteriophage resulted in the appearance of phage-resistant cells which predominated in the culture after 24 h incubation. Interestingly, efficiency of selection of bacteria resistant to vB_Eco4M-7 was higher at higher multiplicity of infection (MOI); the highest efficiency was evident at MOI 10, while the lowest occurred at MOI 0.001. A similar phenomenon of selection of the phage-resistant bacteria was also observed in the experiment with the STEC-contaminated cucumber after 24 h incubation with phage lysate. On the other hand, bacteriophage vB_Eco4M-7 could efficiently develop in host bacterial cells, giving plaques at similar efficiency of plating at 37, 25 and 12 °C, indicating that it can destroy STEC cells at the range of temperatures commonly used for vegetable short-term storage. These results indicate that bacteriophage vB_Eco4M-7 may be considered for its use in food protection against STEC contamination; however, caution should be taken due to the phenomenon of the appearance of phage-resistant bacteria.
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spelling pubmed-84704162021-09-27 A Validation System for Selection of Bacteriophages against Shiga Toxin-Producing Escherichia coli Contamination Necel, Agnieszka Bloch, Sylwia Nejman-Faleńczyk, Bożena Dydecka, Aleksandra Topka-Bielecka, Gracja Węgrzyn, Alicja Węgrzyn, Grzegorz Toxins (Basel) Article Shiga toxin-producing Escherichia coli (STEC) can cause severe infections in humans, leading to serious diseases and dangerous complications, such as hemolytic-uremic syndrome. Although cattle are a major reservoir of STEC, the most commonly occurring source of human infections are food products (e.g., vegetables) contaminated with cow feces (often due to the use of natural fertilizers in agriculture). Since the use of antibiotics against STEC is controversial, other methods for protection of food against contaminations by these bacteria are required. Here, we propose a validation system for selection of bacteriophages against STEC contamination. As a model system, we have employed a STEC-specific bacteriophage vB_Eco4M-7 and the E. coli O157:H7 strain no. 86-24, bearing Shiga toxin-converting prophage ST2-8624 (Δstx2::cat gfp). When these bacteria were administered on the surface of sliced cucumber (as a model vegetable), significant decrease in number viable E. coli cells was observed after 6 h of incubation. No toxicity of vB_Eco4M-7 against mammalian cells (using the Balb/3T3 cell line as a model) was detected. A rapid decrease of optical density of STEC culture was demonstrated following addition of a vB_Eco4M-7 lysate. However, longer incubation of susceptible bacteria with this bacteriophage resulted in the appearance of phage-resistant cells which predominated in the culture after 24 h incubation. Interestingly, efficiency of selection of bacteria resistant to vB_Eco4M-7 was higher at higher multiplicity of infection (MOI); the highest efficiency was evident at MOI 10, while the lowest occurred at MOI 0.001. A similar phenomenon of selection of the phage-resistant bacteria was also observed in the experiment with the STEC-contaminated cucumber after 24 h incubation with phage lysate. On the other hand, bacteriophage vB_Eco4M-7 could efficiently develop in host bacterial cells, giving plaques at similar efficiency of plating at 37, 25 and 12 °C, indicating that it can destroy STEC cells at the range of temperatures commonly used for vegetable short-term storage. These results indicate that bacteriophage vB_Eco4M-7 may be considered for its use in food protection against STEC contamination; however, caution should be taken due to the phenomenon of the appearance of phage-resistant bacteria. MDPI 2021-09-11 /pmc/articles/PMC8470416/ /pubmed/34564648 http://dx.doi.org/10.3390/toxins13090644 Text en © 2021 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Necel, Agnieszka
Bloch, Sylwia
Nejman-Faleńczyk, Bożena
Dydecka, Aleksandra
Topka-Bielecka, Gracja
Węgrzyn, Alicja
Węgrzyn, Grzegorz
A Validation System for Selection of Bacteriophages against Shiga Toxin-Producing Escherichia coli Contamination
title A Validation System for Selection of Bacteriophages against Shiga Toxin-Producing Escherichia coli Contamination
title_full A Validation System for Selection of Bacteriophages against Shiga Toxin-Producing Escherichia coli Contamination
title_fullStr A Validation System for Selection of Bacteriophages against Shiga Toxin-Producing Escherichia coli Contamination
title_full_unstemmed A Validation System for Selection of Bacteriophages against Shiga Toxin-Producing Escherichia coli Contamination
title_short A Validation System for Selection of Bacteriophages against Shiga Toxin-Producing Escherichia coli Contamination
title_sort validation system for selection of bacteriophages against shiga toxin-producing escherichia coli contamination
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8470416/
https://www.ncbi.nlm.nih.gov/pubmed/34564648
http://dx.doi.org/10.3390/toxins13090644
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