[Ravengenocide]

According to this link: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3278644/ phages target specific pathogenic bacteria, and "[...]phages only minimally impact non-target bacteria or body tissues". So that would mean that even though they target bacteria, they would only target a specific bacteria and not all.

[Amadou]

You do have to wonder if they aren't over-stating the specificity. The older I get, the more I come to expect the unstated "but..." on claims like that. As the saying goes, "When it's too good to be true, it probably is."

[bhickey]

I don't think they're overstating this claim. It's a double-edged sword.

If you have an infection your doctor can give you antibiotics and send you home. Antibiotics tend to be wide spectrum and kill entire classes of bacteria, like gram-positive, indiscriminately.

A phage that kills one strain of E.coli might be completely incapable of infecting a closely related E.coli strain. Thinking that a single phage could be effective against closely relate pathogens, for example E.coli AND Salmonella, is wishful thinking. This might have the upside of preserving gut flora, but it's easy to see how it would confound treatment: some things are very difficult to grow in vitro.

[aroch]

Phages will and do target E. Coli and other "pathogenic" bacterium that do in fact reside in your digestive system

[manmal]

Exactly my concern. There are special (very expensive) bacterial supplements (e.g. Mutaflor) which reportedly help people with Colitis Ulcerosa and other inflammatory disease, and they are nothing other than special E. Coli strains. I wouldn't want a supplier to silently introduce something that can kill beneficial gut flora. This is the kind of stuff that lifestyle diseases are made of.