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Persistent little buggers

Ed Yong might be my favorite blogger. He’s certainly the most prolific one I’m aware of (don’t sign up for his twitter feed if you don’t want to be inundated all day long — how do people keep up with that sort of thing?!). But more importantly he’s entertaining and good at what he does.

So imagine my excitement when I saw his byline on a magazine article about one of our very own faculty in the most recent issue of NewScientist. I’ve mentioned Professor Kim Lewis a couple of times, but I don’t think I’ve talked specifically about his theory of “persister” cells.

Yong calls them “sleeper cells” in the article (of the same name) and does a good job explaining the theory, which attempts to explain how some bacterial infections persist after antibiotic treatment.

One common and accepted mechanism is antibiotic resistance. Here individual bacteria with mutations that make them resistant to the drug survive while their un-mutated neighbors die. Over time, all that’s left are strong, antibiotic resistant, mutated bacteria.

Bacterial persistence, on the other hand, says that a small subset of bacterial cells specialize in survival by “going to sleep” when conditions are bad (ie., when an antibiotic comes around).

In the last few years, Lewis and his team have begun to show that bacterial persistence is responsible for disease areas that were previously thought to depend on antibiotic resistance. For example, Cystic Fibrosis patients often die from pneumonia despite the fact that cultures of the incriminating bacteria die when exposed to antibiotics in the lab. In 2010 Lewis’ team showed that these patients actually have significantly more persister cells than normal.

Yong’s article goes into a bit more detail about other researchers in the field who are attempting to find ways to kill off persister cells, for example by punching holes in their cell walls.

You’ll be able to access the full article online for a few days with a free account, but it will soon go behind the paywall and then I can’t do anything for you unless you want to drop by the office and read the paper copy (gasp!).