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Is this part significant?

> A virus from a pond just 40 miles from his house apparently gave him a new lease on life—and gave a new meaning to the term “local medicine.”

That is, are phages for a specific bacterium more likely to be found local to the person infected? Would they have been even more likely to find the right phage if they had collected samples from the patient's neighborhood, family and friends? Nearby people who weren't infected?

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The short answer is no. Bacteria like pseudomonas don't really have geographical ranges because they are not just human pathogens- they are prolific in temperate soils throughout the world. The same species can be found throughout the world and spread from place to place with great ease, and there will be hundreds of pseudomonas phages capable of infecting any given strain. I am fairly confident that you could isolate an infectious phage for this pseudomonas strain from many temperate soils or mucky ponds anywhere in the world. This is not universally true for all bacteria, but is mostly true for bacteria like pseudomonas.

I'm not a doctor or research biologist, but I have the same question. My default assumption is that it depends on whether this is a locally evolved bacterium. If it's a common strain found everywhere then the phage is probably pretty common too. If this is some unusual strain of Pseudomonas that's localized to his area then a phage that coevolved locally with that specific strain might be the most effective fighting it. Either way, it's a probability situation as there's no guarantee a particular phage will fight a particular bacterium until it's tried.

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