Synergistic Interactions among Burkholderia cepacia Complex-Targeting Phages Reveal a Novel Therapeutic Role for Lysogenization-Capable Phages

ABSTRACT Antimicrobial resistance is a danger to global public health and threatens many aspects of modern medicine. Bacterial species such as those of the Burkholderia cepacia complex (Bcc) cause life-threatening respiratory infections and are highly resistant to antibiotics. One promising alternat...

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Main Authors: Philip Lauman, Jonathan J. Dennis
Format: Article
Language:English
Published: American Society for Microbiology 2023-06-01
Series:Microbiology Spectrum
Subjects:
Online Access:https://journals.asm.org/doi/10.1128/spectrum.04430-22
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author Philip Lauman
Jonathan J. Dennis
author_facet Philip Lauman
Jonathan J. Dennis
author_sort Philip Lauman
collection DOAJ
description ABSTRACT Antimicrobial resistance is a danger to global public health and threatens many aspects of modern medicine. Bacterial species such as those of the Burkholderia cepacia complex (Bcc) cause life-threatening respiratory infections and are highly resistant to antibiotics. One promising alternative being explored to combat Bcc infections is phage therapy (PT): the use of phages to treat bacterial infections. Unfortunately, the utility of PT against many pathogenic species is limited by its prevailing paradigm: that only obligately lytic phages should be used therapeutically. It is thought that ‘lysogenic’ phages do not lyse all bacteria and can transfer antimicrobial resistance or virulence factors to their hosts. We argue that the tendency of a lysogenization-capable (LC) phage to form stable lysogens is not predicated exclusively on its ability to do so, and that the therapeutic suitability of a phage must be evaluated on a case-by-case basis. Concordantly, we developed several novel metrics—Efficiency of Phage Activity, Growth Reduction Coefficient, and Stable Lysogenization Frequency—and used them to evaluate eight Bcc-specific phages. Although these parameters vary considerably among Bcc phages, a strong inverse correlation (R2 = 0.67; P < 0.0001) exists between lysogen formation and antibacterial activity, indicating that certain LC phages with low frequency of stable lysogenization may be therapeutically efficacious. Moreover, we show that many LC Bcc phages interact synergistically with other phages in the first reported instance of mathematically defined polyphage synergy, and that these interactions result in the eradication of in vitro bacterial growth. Together, these findings reveal a novel therapeutic role for LC phages and challenge the current paradigm of PT. IMPORTANCE The spread of antimicrobial resistance is an imminent threat to public health around the world. Particularly concerning are species of the Burkholderia cepacia complex (Bcc), which cause life-threatening respiratory infections and are notoriously resistant to antibiotics. Phage therapy is a promising alternative being explored to combat Bcc infections and antimicrobial resistance in general, but its utility against many pathogenic species, including the Bcc, is restricted by the currently prevailing paradigm of exclusively using rare obligately lytic phages due to the perception that ‘lysogenic’ phages are therapeutically unsuitable. Our findings show that many lysogenization-capable phages exhibit powerful in vitro antibacterial activity both alone and through mathematically defined synergistic interactions with other phages, demonstrating a novel therapeutic role for LC phages and therefore challenging the currently prevailing paradigm of PT.
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spelling doaj.art-d38ba35df4e44b9197671aa46e9a3fab2023-06-15T13:18:31ZengAmerican Society for MicrobiologyMicrobiology Spectrum2165-04972023-06-0111310.1128/spectrum.04430-22Synergistic Interactions among Burkholderia cepacia Complex-Targeting Phages Reveal a Novel Therapeutic Role for Lysogenization-Capable PhagesPhilip Lauman0Jonathan J. Dennis1Department of Biological Sciences, University of Alberta, Edmonton, Alberta, CanadaDepartment of Biological Sciences, University of Alberta, Edmonton, Alberta, CanadaABSTRACT Antimicrobial resistance is a danger to global public health and threatens many aspects of modern medicine. Bacterial species such as those of the Burkholderia cepacia complex (Bcc) cause life-threatening respiratory infections and are highly resistant to antibiotics. One promising alternative being explored to combat Bcc infections is phage therapy (PT): the use of phages to treat bacterial infections. Unfortunately, the utility of PT against many pathogenic species is limited by its prevailing paradigm: that only obligately lytic phages should be used therapeutically. It is thought that ‘lysogenic’ phages do not lyse all bacteria and can transfer antimicrobial resistance or virulence factors to their hosts. We argue that the tendency of a lysogenization-capable (LC) phage to form stable lysogens is not predicated exclusively on its ability to do so, and that the therapeutic suitability of a phage must be evaluated on a case-by-case basis. Concordantly, we developed several novel metrics—Efficiency of Phage Activity, Growth Reduction Coefficient, and Stable Lysogenization Frequency—and used them to evaluate eight Bcc-specific phages. Although these parameters vary considerably among Bcc phages, a strong inverse correlation (R2 = 0.67; P < 0.0001) exists between lysogen formation and antibacterial activity, indicating that certain LC phages with low frequency of stable lysogenization may be therapeutically efficacious. Moreover, we show that many LC Bcc phages interact synergistically with other phages in the first reported instance of mathematically defined polyphage synergy, and that these interactions result in the eradication of in vitro bacterial growth. Together, these findings reveal a novel therapeutic role for LC phages and challenge the current paradigm of PT. IMPORTANCE The spread of antimicrobial resistance is an imminent threat to public health around the world. Particularly concerning are species of the Burkholderia cepacia complex (Bcc), which cause life-threatening respiratory infections and are notoriously resistant to antibiotics. Phage therapy is a promising alternative being explored to combat Bcc infections and antimicrobial resistance in general, but its utility against many pathogenic species, including the Bcc, is restricted by the currently prevailing paradigm of exclusively using rare obligately lytic phages due to the perception that ‘lysogenic’ phages are therapeutically unsuitable. Our findings show that many lysogenization-capable phages exhibit powerful in vitro antibacterial activity both alone and through mathematically defined synergistic interactions with other phages, demonstrating a novel therapeutic role for LC phages and therefore challenging the currently prevailing paradigm of PT.https://journals.asm.org/doi/10.1128/spectrum.04430-22bacteriophagephage therapylysogenylysogenizationBurkholderia cepacia complexbacteriophage therapy
spellingShingle Philip Lauman
Jonathan J. Dennis
Synergistic Interactions among Burkholderia cepacia Complex-Targeting Phages Reveal a Novel Therapeutic Role for Lysogenization-Capable Phages
Microbiology Spectrum
bacteriophage
phage therapy
lysogeny
lysogenization
Burkholderia cepacia complex
bacteriophage therapy
title Synergistic Interactions among Burkholderia cepacia Complex-Targeting Phages Reveal a Novel Therapeutic Role for Lysogenization-Capable Phages
title_full Synergistic Interactions among Burkholderia cepacia Complex-Targeting Phages Reveal a Novel Therapeutic Role for Lysogenization-Capable Phages
title_fullStr Synergistic Interactions among Burkholderia cepacia Complex-Targeting Phages Reveal a Novel Therapeutic Role for Lysogenization-Capable Phages
title_full_unstemmed Synergistic Interactions among Burkholderia cepacia Complex-Targeting Phages Reveal a Novel Therapeutic Role for Lysogenization-Capable Phages
title_short Synergistic Interactions among Burkholderia cepacia Complex-Targeting Phages Reveal a Novel Therapeutic Role for Lysogenization-Capable Phages
title_sort synergistic interactions among burkholderia cepacia complex targeting phages reveal a novel therapeutic role for lysogenization capable phages
topic bacteriophage
phage therapy
lysogeny
lysogenization
Burkholderia cepacia complex
bacteriophage therapy
url https://journals.asm.org/doi/10.1128/spectrum.04430-22
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