Evidence of gene transfer via Integrative and Conjugative Elements (ICEs) between bacteria in the human small intestine environment using the dynamic in vitro system TIM-1. - INRAE - Institut national de recherche pour l’agriculture, l’alimentation et l’environnement Access content directly
Conference Papers Year : 2021

Evidence of gene transfer via Integrative and Conjugative Elements (ICEs) between bacteria in the human small intestine environment using the dynamic in vitro system TIM-1.

Abstract

Consumption of food brings large amounts of various bacteria able to interact and exchange genes with the host ones. Gene acquisition can confer novel properties to bacteria (antibiotic resistance, catabolic properties…) which may threat the equilibrium of digestive microbiota or lead to the emergence of new pathogens. Conjugation is the main mechanism of gene acquisition. Gene transfer can occur between strains belonging to the same species but also between very distantly related bacteria. Several classes of mobile genetic elements can be transferred by conjugation, in particular chromosomal elements called Integrative and Conjugative Elements (ICEs), a widespread but poorly known class of elements. To give a first insight on the incidence of gene transfers mediated by ICEs in the human digestive ecosystem, we evaluated their occurrence between dietary and intestinal commensal bacteria during digestion, using the TIM-1 model able to mimic gastric and small intestine environment. Different pairs of ICE donors (Streptococcus thermophilus, S. salivarius) and receptors (S. thermophilus, S. salivarius, Enterococcus faecalis) were immobilized on alginate/agar/chitosan beads and maintained in the jejunum and the ileum of the TIM-1 during milk digestion. Generation of transconjugants (receptors integrating ICE) was evaluated after an exposure of 5h to those conditions, and compared to exposure to undigested milk and M17 broth. Among the 11 pairs tested, 4 gave transconjugants during in vitro digestion whereas all generated conjugates in milk and/or M17. Remarkably, two pairs involved transfer between different genera (S. thermophilus x E. faecalis), whereas the other two involved the same species (S. thermophilus x S. thermophilus). Our study highlights that gene acquisition via transfer of ICEs should occur relatively frequently in the human digestive environment. Moreover, the use of dynamic in vitro models such as the TIM-1 gives a good alternative to in vivo study, to explore such phenomenon easily without ethical constraints.
No file

Dates and versions

hal-03395998 , version 1 (22-10-2021)

Identifiers

  • HAL Id : hal-03395998 , version 1

Cite

Sylvain Denis, Pauline Herviou, Johan Staub, Carine Mazal, Christine Delorme, et al.. Evidence of gene transfer via Integrative and Conjugative Elements (ICEs) between bacteria in the human small intestine environment using the dynamic in vitro system TIM-1.. 12. International Symposium on Gut Microbiology, Oct 2021, En ligne, France. ⟨hal-03395998⟩
55 View
0 Download

Share

Gmail Facebook X LinkedIn More