Phage therapy—constraints and possibilities

Abstract

The rise of antibiotic-resistant bacterial strains, causing intractable infections, has resulted in an increased interest in phage therapy. Phage therapy preceded antibiotic treatment against bacterial infections and involves the use of bacteriophages, bacterial viruses, to fight bacteria. Virulent phages are abundant and have proven to be very effective in vitro, where they in most cases lyse any bacteria within the hour. Clinical trials on animals and humans show promising results but also that the treatments are not completely effective. This is partly due to the studies being carried out with few phages, and with limited experimental groups, but also the fact that phage therapy has limitations in vivo. Phages are large compared with small antibiotic molecules, and each phage can only infect one or a few bacterial strains. A very large number of different phages are needed to treat infections as these are caused by genetically different strains of bacteria. Phages are effective only if enough of them can reach the bacteria and increase in number in situ. Taken together, this entails high demands on resources for the construction of phage libraries and the testing of individual phages. The effectiveness and host range must be characterized, and immunological risks must be assessed for every single phage.

Key words::

• Antibiotic resistance
• bacteriophage
• phage
• phage therapy

Acknowledgements

The author wishes to honour Professor Otto Cars for his research achievements and efforts to contain antibiotic resistance. The author would also like to express his gratitude to The Olle Engkvist Foundation for financial support.

Declaration of interest: The author declares that no conflict of interest exists. No financial disclosures were reported by the author of this paper.