Journal
APPLIED AND ENVIRONMENTAL MICROBIOLOGY
Volume 79, Issue 23, Pages 7390-7397Publisher
AMER SOC MICROBIOLOGY
DOI: 10.1128/AEM.02184-13
Keywords
-
Categories
Funding
- Danish Council for Independent Research, Technology, and Production Sciences [09-066098 (274-08-0531)]
Ask authors/readers for more resources
Listeria monocytogenes can cause the serious infection listeriosis, which despite antibiotic treatment has a high mortality. Understanding the response of L. monocytogenes to antibiotic exposure is therefore important to ensure treatment success. Some bacteria survive antibiotic treatment by formation of persisters, which are a dormant antibiotic-tolerant subpopulation. The purpose of this study was to determine whether L. monocytogenes can form persisters and how bacterial physiology affects the number of persisters in the population. A stationary-phase culture of L. monocytogenes was adjusted to 10(8) CFU ml(-1), and 10(3) to 10(4) CFU ml(-1) survived 72-h treatment with 100 mu g of norfloxacin ml(-1), indicating a persister subpopulation. This survival was not caused by antibiotic resistance as regrown persisters were as sensitive to norfloxacin as the parental strain. Higher numbers of persisters (10(5) to 10(6)) were surviving when older stationary phase or surface-associated cells were treated with 100 mu g of norfloxacin ml(-1). The number of persisters was similar when a Delta sigB mutant and the wild type were treated with norfloxacin, but the killing rate was higher in the Delta sigB mutant. Dormant norfloxacin persisters could be activated by the addition of fermentable carbohydrates and subsequently killed by gentamicin; however, a stable surviving subpopulation of 10(3) CFU ml(-1) remained. Nitrofurantoin that has a growth-independent mode of action was effective against both growing and dormant cells, suggesting that eradication of persisters is possible. Our study adds L. monocytogenes to the list of bacterial species capable of surviving bactericidal antibiotics in a dormant stage, and this persister phenomenon should be borne in mind when developing treatment regimens.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available