#Intestinal #Bile Acids Induce a Morphotype Switch in #Vancomycin-Resistant #Enterococcus that Facilitates Intestinal Colonization (Cell Host Microbe, abstract)

[Source: Cell, Host & Microbe, full page: (LINK). Abstract, edited.]

Intestinal Bile Acids Induce a Morphotype Switch in Vancomycin-Resistant Enterococcus that Facilitates Intestinal Colonization

Peter T. McKenney, Jinyuan Yan, Julien Vaubourgeix 8, Simone Becattini, Nina Lampen, Andrew Motzer, Peter J. Larson, Daniel Dannaoui, Sho Fujisawa, Joao B. Xavier, Eric G. Pamer 9

Published: April 25, 2019 / DOI: https://doi.org/10.1016/j.chom.2019.03.008



  • VRE forms long chains and biofilms in physiological concentrations of bile acids
  • This morphotype switch is reversed by cations
  • Selection against chaining is linked to sensitivity to the antibiotic daptomycin
  • Chaining-deficient VRE mutants exhibit reduced persistence in the gut



Vancomycin-resistant Enterococcus (VRE) are highly antibiotic-resistant and readily transmissible pathogens that cause severe infections in hospitalized patients. We discovered that lithocholic acid (LCA), a secondary bile acid prevalent in the cecum and colon of mice and humans, impairs separation of growing VRE diplococci, causing the formation of long chains and increased biofilm formation. Divalent cations reversed this LCA-induced switch to chaining and biofilm formation. Experimental evolution in the presence of LCA yielded mutations in the essential two-component kinase yycG/walK and three-component response regulator liaR that locked VRE in diplococcal mode, impaired biofilm formation, and increased susceptibility to the antibiotic daptomycin. These mutant VRE strains were deficient in host colonization because of their inability to compete with intestinal microbiota. This morphotype switch presents a potential non-bactericidal therapeutic target that may help clear VRE from the intestines of dominated patients, as occurs frequently during hematopoietic stem cell transplantation.

Keywords: Enterococcus – VRE – bile – microbiota – morphotype – faecium – faecalis – colonization resistance

Keywords: Antibiotics; Drugs Resistance; Vancomycin; Daptomycin; Enterococcus.


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Giuseppe Michieli

I am an Italian blogger, active since 2005 with main focus on emerging infectious diseases such as avian influenza, SARS, antibiotics resistance, and many other global Health issues. Other fields of interest are: climate change, global warming, geological and biological sciences. My activity consists mainly in collection and analysis of news, public services updates, confronting sources and making decision about what are the 'signals' of an impending crisis (an outbreak, for example). When a signal is detected, I follow traces during the entire course of an event. I started in 2005 my blog ''A TIME'S MEMORY'', now with more than 40,000 posts and 3 millions of web interactions. Subsequently I added an Italian Language blog, then discontinued because of very low traffic and interest. I contributed for seven years to a public forum (FluTrackers.com) in the midst of the Ebola epidemic in West Africa in 2014, I left the site to continue alone my data tracking job.