Phage therapy is super interesting, but there are a lot of technical problems. If I ever leave software engineering, it'll be to go back to mucking around with phage.

Immune clearance: The immune system really enjoys soaking up phage. Blood titers drop stupidly fast. Maybe we could flood the colon with a phage-bearing solution to handle GI infections, but in general I'm really skeptical. There was a paper ~8 years ago describing serial passages in rabbits to enrich for immunocompatible phage. Don't know if further work has been done here.

Specificity: Phage really, really like their hosts. I had a strain of Phi X174 in lab that would simply never infect wild type E coli. To deploy phage effectively, you need to culture whatever it is that you're after. Next you'd want to infect the pathogen in culture and pass your phage for O(many) generations. A lot of human pathogens are just miserable to grow.

Efficacy: Antibiotics are just better at killing bacteria (resistance aside.)

Regulatory: You'd need to convince the FDA to approve a viral cocktail that is potentially going to kill the patient through anaphylaxis.

Indeed, the name of one of the major hospital-acquired human pathogens, Clostridium difficile, literally means "Clostridium pain in my ass to culture".

I once tried to grow magnetotactic bacteria. For the growth media, you had to prepare a witch's brew of unusual chemicals which sent me on a goose hunt around a few friendly chem labs. The protocol called for making a couple of litres; smaller quantities would just exacerbate measurement errors. After cooking it up, you were supposed to add 2mL to the growth media and incubate the whole mess for four weeks.

Needless to say, I could never get them to grow.

Edit: I found the protocol!

NTA 1.5g

MgSO4 3.0g

MnSO4 0.5g

NaCl 1.5g

FeSO4 0.1g

CaCl2 0.1g

CoSO4 0.1g

ZnSO4 0.1g

CuSO4 0.025g

AlK(SO4)2 0.01g

H3BO3 0.01g

Na2MoO4 0.4g

NiCl2 0.01g

Phew. Did I mention: it was an anaerobe? Flushing an exotic growth media with nitrogen is a dull way to spend a Friday afternoon.

Perhaps:

http://www.the-scientist.com/?articles.view/articleNo/44785/...

It does seem to be undergoing a growth in interest in the research and development communities. I suspect that this might get squashed by the newfound ability to discover new classes of antibiotics pretty much as needed, however:

http://www.popsci.com/ichip-new-way-find-antibiotics-and-oth...

A start-up from Boston called Sample6 is using phages in diagnostics, currently only for food but it is start. I would be very afraid it ends up like the introduction of Mongoose to Hawaii to control rats in the 19th century.

> I would be very afraid it ends up like the introduction of Mongoose to Hawaii to control rats in the 19th century.

There's no way for them to jump domains prokaryotes to eukaryotes. It's just biologically implausible. Phage are very narrow spectrum and coevolve with their hosts. They're all over our environment and have been since just about the dawn of life.

Hypothetically, I guess you could accidentally sterilize your gut flora, but again: they aren't broad spectrum.

The biggest risk for phage therapy is an adverse reaction to bacterial endotoxins as the phages cause them to lyse.