Phage Therapy Pt. 3

When we propose the bacteriophage as an alternative to antibiotic antimicrobial treatments, we cannot ignore the possible resistance issues with phage therapy. As many readers know, bacteria are becoming more and more resistant to traditional antibiotic treatments. Phage therapy is often celebrated as the antibiotic resistance miracle cure however it is important to remember that bacteria can and will develop resistance to any form of therapy including phage because of their ability to transfer genes horizontally. Because phage are subject to the same nary a of selection that cause antibiotic resistance, the phage that successfully kill bacteria will be those that can infect bacteria and will release their progeny. This back and forth battle between bacteria and bacteriophage has been likened to an "evolutionary arms race"- an apt analogy. The outcome of this arms race is, even theoretically, largely unstudied. Bruce Levin of Emory University and James Bull of the University of Texas at Austin published an article in 2004 on many of these issues of resistance and evolution. The article puts forth the idea that bacterial resistance could proceed so that the mechanisms of virulence are simultaneously disabled along with the bacterium's susceptibility to bacteriophage infection. In other words, the cell receptors that allow bacteriophage to attach to the exterior of a bacterial cell could be eliminated so that the bacteria could resist phage attack. Mutants who lose these receptors might also lose their ability to attach to tissues in humans (the exterior cell receptors are responsible for host pathogenesis). This hypothesis merits further study.