Phage therapy is an approach in which viruses (bacteriophages or phages) fight specific pathogenic bacteria while leaving beneficial bacteria, people, animals and plants unharmed.
A phage fights a certain bacteria by specifically attaching itself to it and injecting its hereditary material into the bacteria cell. The bacterial cell is disabled as a result and will then start producing many completely new phages. Since the phages make holes in the cell wall from the inside out (lysis), this dies off. The phages that are then released re-attach themselves to a new prey and this cycle repeats itself. In addition to phage therapy, it is also possible to use the enzymes caused by this lysis for specific anti-bacterial activities. This is known as lysine therapy.
Bacterial infections
Phage therapy has been around since the beginning of the previous century. In the Western world, this method decreased in popularity due in part to the fact that antibiotics became available for the treatment of bacterial infections. Over the years however, there has been increased resistance to the use of antibiotics. The demand for other forms of anti-pathogenic treatment (such as phage therapy) has increased as a result.
Anti-pathogenic treatment
The Central veterinary Institute at Wageningen UR is carrying out research into various applications of phage and lysine therapy to improve food safety and animal health.
Each year in the Netherlands, some 130,000 people become infected with Campylobacter and Salmonella, primarily through contaminated food. The research in the field of phage therapy is currently focusing on fighting pathogenes such as Campylobacter.
Salmonella and Campylobacter
Phage therapy has not yet been applied in practice to fight Salmonella and Campylobacter. This is not due to any doubts regarding the safety of this therapy, but because there are still practical obstacles to this which are preventing large-scale cost-effective application. Among other areas, the study is focusing on determining the most suitable “product” (live animals, carcasses, end products) in order to obtain the most possible human health benefits (lower incidence of disease) using a low dosage of phages. Studies are also being carried out to determine the risk of developing resistance which can also occur as a result of phage therapy. A combination of phages must be used for Campylobacter in order to fight all of the strains of Campylobacter. The effectiveness of a combination of treatments is being studied.
Animal health
This study focuses primarily on the development of phage and lysine therapy to fight Streptococcus suis infections in pigs. S. suis is one of the most important bacterial infections in the pig production sector, and can result in serious symptoms such as meningitis (inflammation of the cerebral membrane) and arthritis (inflammation of the joints). Antibiotics are often used to treat these conditions. Selected by ImmunoValley, this project falls within the ' Alternatives to antibiotics' (ALTANT) program of the Ministry of Agriculture, Nature and Food Quality.
Food safety
Research has shown that the use of phages in live animals (broiler chicks) can yield a reduction in Campylobacter and Salmonella. In the CARMA (Campylobacter Risk Management and Assessment) project, it has been established that a reduction in the number of Campylobacter bacteria in live broiler chicks will have a positive effect on the human health problems associated with Campylobacter. In the recently started current project, phages and lysines are isolated, described, purified and produced. The most suitable candidates are tested for their applicability in practice. Among other conclusions, it has become clear that the combination of the type of infection, phage and host is very significant for the final result.
From: wur.nl