Modified bacteriophage

Inventors

Fairhead, Heather • Wilkinson, Adam • Holme, Sarah • Pitts, Katy • Jackson, Alison

Assignees

Phico Therapeutics Ltd

Abstract

Provided is a modified bacteriophage capable of infecting a target bacterium, which bacteriophage includes an α/β small acid-soluble spore protein (SASP) gene encoding a SASP which is toxic to the target bacterium, wherein the SASP gene is under the control of a constitutive promoter which is foreign to the bacteriophage and the SASP gene.

Core Innovation

The described invention provides a modified bacteriophage able to replicate in a bacterial host and to infect target bacteria while carrying an α/β small acid-soluble spore protein (SASP) gene encoding a SASP that is toxic to the bacterial host. The SASP gene is inserted into a lysis gene of the bacteriophage and is under the control of a constitutive bacterial promoter foreign to the bacteriophage. The phage comprises a single copy of the SASP gene linked to the constitutive bacterial promoter.

A foreign constitutive promoter drives SASP gene expression independently of phage life-cycle promoters, producing non-lethal SASP levels in the phage-manufacturing host under single-copy conditions. Upon infection in target cells, expression increases with multiple copies, resulting in toxic SASP levels that are associated with killing. The described SASP mechanism includes DNA binding and a B-like to A-like DNA conformation.

A preferred construction replaces or inactivates an α/β holin gene to create a non-lytic bacteriophage while inserting an fbaA::SASP-C construct and a non-antibiotic cadmium resistance marker (CdR). The document also states advantages over prior SASP-phage designs that relied on phage life-cycle promoters, including independent SASP expression, a delivery role despite narrow phage host range, and compatibility with superinfection/prophage contexts in which superinfection immunity does not prevent SASP inhibition.

Claims Coverage

The partial content identifies two independent claims that cover production of replication-competent modified bacteriophages carrying a toxic SASP gene under a foreign constitutive bacterial promoter, with defining features on single-copy placement linked to the promoter and insertion into a lysis/holin gene, including a specific non-lytic holin-gene configuration in the other independent claim. Across the independent claims, the coverage centers on producing the modified phage by growing a bacterial host carrying the phage genetic material, then causing replication and harvesting the phage with the specified SASP/promoter and lysis-gene arrangements.

Both independent claims define production of a replication-competent modified bacteriophage by growing a bacterial host carrying phage genetic material and harvesting the replicated phage, while specifying that a toxic SASP gene is under a foreign constitutive bacterial promoter and is positioned within a lysis/holin gene context, with one independent claim emphasizing single-copy SASP gene presence linked to the constitutive promoter and the other specifying ϕ11 holin-gene insertion carrying Bacillus megaterium SASP-C under an fbaA constitutive promoter.

Stated Advantages

Documented Applications