Outwitting Germs that Never Say Die

The following is the article discussed: http://www.boston.com/business/healthcare/articles/2010/03/15/researchers_trying_to_outwit_undead_germs_that_may_cause_chronic_infections/

This is the paper in the Public Library of Science which the article discusses: http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1000317

We’ve learned that when the survival of a bacteria is threatened it can retreat in effect to a dormant stage, which will allow it to become active once more in the future, and protect it from whatever external conditions are capable of destroying it.  There is an additional form that some bacteria can take, they are called “persisters”.  These persisters are essentially dormant cells, but the key difference that the literature I’ve looked at discusses is that these cells are highly tolerant of antibiotics, to the point where some antibiotics used to target bacterial DNA may actually induce bacteria to enter this persister state.  Because of their ability to seemingly return from the dead, persisters have been likened to zombies by several investigators working in the field.

Persisters had been present in scientific discourse since 1944, however there hadn’t been much research devoted to them until recently.  Even in the early 2000s, persisters were referred to as hypothetical constructs whose existence hasn’t been effectively tested.  Recently there has been increased interest in persisters, precisely because not much is known about them, but the medical ramifications of their existence could be very important in patient care.

An article in the Boston Globe outlines the research of Dr. Kim Lewis, at Northeastern University.  Dr. Lewis has been working on isolating one of the ways E.Coli is provoked into entering a persister state.  While very few cells may actually become persisters, an amount as small as 1% in a bacterial film, they could bring back previously had diseases by re-growing the population.  Dr. Lewis and colleagues administered ciproflaxin, which is an antibiotic that targets and damages the DNA of bacteria, to E.Coli, and found that some cells have a repair response which resulted in the bacteria forming certain proteins, one of which when present in large numbers, results in presisters.

The potential for the application of knowledge surrounding persisters could be fundamental to improving patient care, particularly looking at the rate of infections in hospitals.  Reinfection could be understood more clearly, as well as the general knowledge of bacterial survival.

Dr. Lewis received funding from a source that particularly funds what the article calls “innovative and risky research projects,” so one reason for the lack of research in this area despite the possibility of enormous benefit could be a lack of financial will.  Traditionally governments haven’t been too vocal about supporting basic research, and when encountering a virtually unknown area of study, basic research is what is necessary.  As researchers such as Dr. Lewis make gains studying persisters however, it is likely that additional research will appear, and hopefully more than one method of creating persisters will be identified.

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