Chapter 31 – Antimicrobial Phages

Since their discovery near the beginning of the 20th century lytic viruses of bacteria known as bacteriophages (phages), have been widely used as antimicrobial agents even prior to their characterization as viruses. Early studies demonstrated their potential to treat infections in large but poorly described trials in cholera and dysentery patients. Phage therapy was commercialized by several large companies in the 1920s and 1930s but preparations were heterogeneous in quality and were recommended for the treatment of diseases that did not have a bacterial aetiology. The introduction of antibiotics into human and veterinary medicine side-lined the use of phage to pockets of use in countries in Eastern Europe and the countries of the former USSR where they are still used today. Phages were central to early discoveries in molecular biology and this and studies in animal models of infection in the 1980s led to a revival in interest as therapeutic agents. More recently, several early-stage clinical trials have been performed to demonstrate their safety in topical applications and a small phase 2/2a study showed efficacy in the treatment of antibiotic-resistant otitis. Phage genomics is still at an early stage and most phage genes are of unknown function, however expanding antibiotic resistance and a paucity of novel antibiotics has generated recent, further interest in their therapeutic development built upon genetically characterized bacteriophages.