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Proc Natl Acad Sci U S A. 2017 Jun 13;114(24):6334-6339. doi: 10.1073/pnas.1702077114. Epub 2017 May 30.

Deciphering the landscape of host barriers to Listeria monocytogenes infection.

Author information

1
Division of Infectious Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115.
2
Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115.
3
Department of Pharmacy, University of Tromso, The Arctic University of Norway, 9037 Tromso, Norway.
4
Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06510.
5
Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan.
6
Division of Infectious Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115; mwaldor@research.bwh.harvard.edu.
7
Howard Hughes Medical Institute, Boston, MA 02115.

Abstract

Listeria monocytogenes is a common food-borne pathogen that can disseminate from the intestine and infect multiple organs. Here, we used sequence tag-based analysis of microbial populations (STAMP) to investigate Lmonocytogenes population dynamics during infection. We created a genetically barcoded library of murinized Lmonocytogenes and then used deep sequencing to track the pathogen's dissemination routes and quantify its founding population (Nb) sizes in different organs. We found that the pathogen disseminates from the gastrointestinal tract to distal sites through multiple independent routes and that Nb sizes vary greatly among tissues, indicative of diverse host barriers to infection. Unexpectedly, comparative analyses of sequence tags revealed that fecally excreted organisms are largely derived from the very small number of L. monocytogenes cells that colonize the gallbladder. Immune depletion studies suggest that distinct innate immune cells restrict the pathogen's capacity to establish replicative niches in the spleen and liver. Finally, studies in germ-free mice suggest that the microbiota plays a critical role in the development of the splenic, but not the hepatic, barriers that prevent L. monocytogenes from seeding these organs. Collectively, these observations illustrate the potency of the STAMP approach to decipher the impact of host factors on population dynamics of pathogens during infection.

KEYWORDS:

Listeria monocytogenes; STAMP; pathogen dissemination; pathogen transmission; population dynamics

PMID:
28559314
PMCID:
PMC5474794
DOI:
10.1073/pnas.1702077114
[Indexed for MEDLINE]
Free PMC Article

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