“Bacteriophages represent a totally different approach to antimicrobial therapy and offer the potential to treat a wide range of diseases, particularly those caused by antibiotic-resistant bacterial strains”
Bacteriophages are the world’s most abundant organisms. It’s estimated that the total number of bacteriophages on Earth exceeds ten thousand billion billion billion (10³¹). They prey only on bacteria, never on human cells or those of any more complex organism. While resistance mechanisms do exist, as living organisms, bacteriophages are constantly changing and adapting alongside their host bacteria, bypassing the development of resistance.
Even among their bacterial hosts, bacteriophages are highly specific, with most infecting only a single species of bacteria. In many cases, only specific strains within that species are infected.
Once the bacteriophage has infected the host cell, the resulting infection may be either lytic, reprogramming and then destroying the infected cell, or lysogenic, where the bacteriophage genome is integrated into the bacterial genome and passed on to future generations of bacteria. Lysogenic bacteriophages may also reactivate, producing a new generation of viruses.
Lytic bacteriophages are the type used for most therapeutic approaches. A typical lytic bacteriophage will produce hundreds of new bacteriophages from an infected bacterial cell in a matter of hours. These can then go on to infect and destroy yet more of the target bacteria. This exponential replication only stops when the bacteriophages run out of target bacteria. Then, they cannot grow any more. Without their target, they are simply small lumps of protein and nucleic acid, to be removed by the normal clearance processes of the body.
AmpliPhi Biosciences has applied its knowledge of bacteriophage to the generation of novel therapeutic solutions including BioPhage-PA and BioPhage-PR. As leading innovators in bacteriophage research, we are pleased to be able to translate the promise of bacteriophages into applicable treatment approaches that hold promise to have a significant impact on the control of bacterial infections.
More than ninety per cent of known bacteriophages have a head containing the double-stranded DNA genome and an attached tail through which the DNA can pass into the cell.
This tail can be long or short, flexible or stiff, and is a key characteristic of the different families of bacteriophages. Fibers at the end of the tail find specific receptors on the surface of target bacteria.
The virus then binds and its DNA enters into the host bacterial cell. For bacteriophages like the one pictured, this process is similar to a hypodermic injection.