"Phage therapy" is short for bacteriophage therapy. Bacteriophage are viruses that kill bacteria .The basic concept of phage therapy is to introduce the phage into an infected patient. The phage infects the bacterium–an infection of an infection! Then the phage multiply within the bacterium, explode from the inside the host bacterium and move onto the next bacterium. Essentially, you have a self-manufacturing antibiotic.

Phages have been used for a long time — since about 1915 in fact, and were soon regarded as an effective treatment for infection (they were discovered independently by English, French-Canadian, and Georgian doctors). American pharmaceutical giant Eli Lilly was even making them for a time.

Then, in 1941, penicillin hit the market. Hit the market in the West, that is, where it was regarded as miraculous, putting phages out of business. However, there was a long-term price for the miracle: Our reliance on antibiotics soon caught up with us. Stronger antibiotics forced bacteria to evolve into drug-resistant strains.

So that's the concept, but does it actually work? Success rates are typically equivalent to traditional antibiotics. Phage therapy has two other advantages: it's very cheap (which is probably why it is unavailable to us now), and the phage are far more robust to heat than some antibiotics (no refrigeration needed). But the best part is that the bacterium does not develop a resistance as they do with traditional antibiotics.

There can be some treatment side effects. Often, when exposed to phage, bacteria enter what can be called a “panic mode” where the bacteria produce every nasty little thing they can including all sorts of toxins (if they have toxin-producing capability). This can happen with traditional antibiotics too; however, the presence of traditional antibiotics can also lower toxin production.

Ultimately, the advantage and the disadvantage of phage therapy is that it is a narrow spectrum treatment: a particular phage works against a certain species (or even a subset of a species). The disadvantage is that you have to know something about the infectious bacterium such as what species it is, and such diagnoses can take several days that many patients do not have. Phage therapy won't be a magic bullet. But, hopefully, phage therapy will become one more tool we can use to stop the evolution of antibiotic resistance.

Here in the US, the FDA would require every phage to go through a multi-year testing process – by which time the bug may have evolved again. There is hope, although it may be a while coming here because of the FDA approval rules. But, there are a handful of Western companies — Intralytix (in Baltimore), Novolytics (in the U.K.), and GangaGen (in Bangalore, California, and Ontario) — working to bring phage therapy to our market.

There's also the possibility that phages can be used for animals, even if they aren't approved for humans, which would improve our dairy and meat supplies.

And, of course, even if phage clinics never cross our borders, Tijuana isn't far too go to save someone's life — even though it is so strange that we should have to do that.