A Targeted Alternative to Antibiotics?

Bacteriophages offer a novel sustainable alternative to the\r\nuse of antibiotics in aquaculture, according to Proteon Pharmaceuticals – a\r\nstart-up that’s looking to break into the commercial aquaculture sphere.

The Fish Site caught up with Proteon’s Matthew Tebeau and Aneta\r\nBronowska at last week's Aquaculture\r\nInnovation Europe conference to find out more.

How do bacteriophages\r\nwork?

They kill bacteria through a process called lysing in which\r\nthey attach to the bacteria, inject their DNA and force the bacteria to\r\nreproduce their DNA until it explodes the cell wall of the bacteria. Although\r\nthey are comparable to an antibiotic, in that they directly kill bacteria, an\r\nantibiotic is like a nuclear bomb and kills everything, meaning the microbiome\r\nhas to repopulate itself and there’s collateral damage to commensal bacteria,\r\nwhile a bacteriophage kills a specific species of pathogenic bacteria.

Phages are a natural part of the microbiome, but a\r\nconcentrated cocktail of specifically selected bacteriophages can be used to\r\nkill specific diseases or bacteria. The bacteria we’ve targeted can cause high\r\nmortalities in aquaculture but phages can treat this swiftly. Our product can\r\nalso be used prophylactically by forward-thinking farmers looking to prevent\r\nmortalities.

Is it possible to\r\ntarget specific pathogens?

We can either use a particular phage or cocktail to target\r\nparticular bacteria, such as a Salmonella or Pseudomonas, or we\r\ncan develop a cocktail to target a whole range of bacteria.

Which bacteria are\r\nyou targeting at the moment in aquaculture?

We’re currently targeting Pseudomonas and Aeromonas –\r\nwhich are responsible for a large proportion of pond aquaculture disease\r\noutbreaks in India, for example – but we also have a product for vibrio in the\r\npipeline for the shrimp sector and we also have a series of developments\r\nfocusing on other bacterial targets like Renibacterium.

Which aquaculture\r\nsectors will these phages be most useful for?

Our first product, Bafador, kills Pseudomonas and\r\nAeromonas and is aimed at sectors including salmon, rainbow trout, carp,\r\neel and catfish. It was only launched this spring and the response from\r\nproducers has been even better than we expected, with early adopters including\r\nArctic char and rainbow trout farmers.

How are your phages\r\ndelivered?

Mainly in the feeds, but also via immersive bath treatments.

Can they be used in\r\ndifferent production systems?

Yes, indeed, Bafador has been designed to be used in a\r\nvariety of production systems – in both fresh and salt water.

Are there any\r\nregulatory constraints?

The regulatory environment for phages really varies from\r\nmarket to market, so it’s a bit of a challenge, but it’s registered as a feed\r\nadditive in Asia at the moment, and you can also use it as part of an\r\nautogenous vaccine.

What’s the level of\r\nefficacy?

The field results have confirmed our trials that it reduces\r\nmortalities by over 80 percent – it basically stops a disease event in its\r\ntracks and, typically, there is no reoccurrence.

What are your current\r\nambitions?

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We’re looking for investors to support our\r\ncommercialisation, whether private equity or industrially connected; we are\r\nalso looking to partner with veterinary groups, feed producers and leading\r\nproducers who have products or technologies that can fit with what we’re doing.\r\nThese could be partnerships in terms of delivery methods, formulation\r\nmethodologies, in terms of diagnostics, or in terms of complementary products:\r\nif we can deliver one part of a solution that’s great.

Source : The Fish SIte