Chemical antibiotics are currently the best and most developed tool we have for bacterial infection, but other options are being explored, including defensins[1,2,3] (antimicrobial peptides) and—as mentioned in the article—phage therapy[4,5,6,7] (viruses that infect and replicate within a bacterium). Like many of our current antibiotics, they have their origins in nature. As therapeutics, they're far off, and would have to be characterized and go through the usual clinical trial process to be evaluated for efficacy and safety. Specificity is an issue for phages, and delivery is a challenges for both. One novel application is a defensin-based chewing gum being developed by the US military to combat the bacteria responsible for dental plaque[8,9].

1. http://www.nature.com/nri/journal/v3/n9/full/nri1180.html

2. https://en.wikipedia.org/wiki/Defensin

3. http://onlinelibrary.wiley.com/doi/10.1002/biot.200700148/ab...

4. http://www.nature.com/news/phage-therapy-gets-revitalized-1....

5. https://www.amazon.com/Forgotten-Cure-Future-Phage-Therapy/d...

7. https://en.wikipedia.org/wiki/Phage_therapy

8. http://www.newyorker.com/tech/elements/zero-dark-cavity

9. http://www.usaisr.amedd.army.mil/news/news_stories/2014_FEB/...