Natural phages

Phages are the natural predators of bacteria.They are the most ubiquitous (numerous) biological species on Earth. Phages are present in all aquatic and terrestrial environments (and so called natural). They are viruses that only infect bacteria. They are not capable of infecting eukaryotic cells (human, animal, fungus, plants and insects).

General

phage structure

Bacteriophages may have a lytic or lysogenic cycle and some combine both. With lytic phages such as T4, the bacterial cells are lysed immediately after replication of the virion.

Once the cell is destroyed, the newly created phages can find new hosts to promote a new cycle.

At the other end, lysogenic phages can propagate without killing the bacterial host.

Consequently, Pherecydes Pharma selects and produces exclusively lytic phages.

Picture source: The Portal to Science, Engineering, and Technology

Bacteriophage cycle

Download the cycle diagram

The infectious cycle begins with the bacteriophage specific recognition of receptor(s) located on the surface of the bacteria.

In a second step, the bacteriophage genetic material is injected into the cytoplasm of the bacterium. Then, phage proteins and/or gene material take over the host cellular machinery to produce large numbers of new phage genomes and protein structures.

After an assembling step, the new virions are formed and break out into the external medium as the lysis (dissolution) of the bacterium takes place.

The proliferation of bacteriophages is fast and is always dependent on the presence of a host bacteria.

See three different “morphotypes” bacteriophages.

Therapeutic applications have already been tested

For decades, various bacterial infections (i.e. pulmonary, cutaneous, gastrointestinal, etc.) have been treated with bacteriophages in Georgia, Poland, Russia, either alone or in combination with antibiotics. Unfortunatly, no clinical studies have been performed under todays’s Western drug development standards and no phage treatment is approved in Western Europe or the USA.

Thanks to its unique expertise in the characterisation and selection of lytic phages, Pherecydes Pharma is building a large collection of phages. The most efficacious ones are selected and produced to generate drug products to fight bacterial infections, including antibiotic-resistant ones.

Screening and characterization of phage

Pherecydes Pharma has developed an internal screening process, supported by large collections of E. coli, Pseudomonas aeruginosa and staphylococci bacterial strains, including multidrug-resistant and nosocomial germs. Thus, Phercydes Pharma masters a complete system for developing therapeutic phage cocktails with high specificity against pathogens.

Various tests performed in vivo, against different infections carried out by antibiotic multidrug-resistant bugs (E. coli or P. aeruginosa) have demonstrated dramatic results in terms of efficacy and safety, without side effect. Now, the first products are being evaluated clinically, according to the best European standards applied in this field.


The Company is working in parallel to optimize the product formulation, the stability over time and the manufacturing process.