Bacterial populations contain persisters, phenotypic variants that constitute approximately 1% of cells in stationary phase and biofilm cultures. Multidrug tolerance of persisters is largely responsible for the inability of antibiotics to completely eradicate infections. Recent progress in understanding persisters is encouraging, but the main obstacle in understanding their nature was our inability to isolate these elusive cells from a wild-type population since their discovery in 1944.
We hypothesized that persisters are dormant cells with a low level of translation, and used this to physically sort dim E. coli cells which do not contain sufficient amounts of unstable GFP expressed from a promoter whose activity depends on the growth rate. The dim cells were tolerant to antibiotics and exhibited a gene expression profile distinctly different from those observed for cells in exponential or stationary phases. Genes coding for toxin-antitoxin module proteins were expressed in persisters and are likely contributors to this condition.
We report a method for persister isolation and conclude that these cells represent a distinct state of bacterial physiology.
bacteria, persisters, multidrug tolerance, antibiotics
Multidrug resistance, Antibiotics, Drug resistance in microorganisms, Escherichia coli
Copyright 2006. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Devang Shah, Zhigang Zhang, Arkady B. Khodursky, Niilo Kaldalu, Kristi Kurg, Kim Lewis
Shah, Devang; Zhang, Zhigang; Khodursky, Arkady B.; Kaldalu, Niilo; Kurg, Kristi; and Lewis, Kim, "Persisters: a distinct physiological state of E. coli" (2006). Biology Faculty Publications. Paper 11. http://hdl.handle.net/2047/d20000892
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Additional Filespersisters gene expression data.xls (208 kB)