​​Understanding the phenotypical heterogeneity between diverse species or strains after antibiotic treatment​

Antibiotics have been used for decades; their targets and modes of action have been extensively studied, but primarily using model organisms and common pathogens. A growing body of evidence suggests that the way antibiotics affect diverse species or strains is sometimes different from what is described in textbooks. We, for example, discovered that macrolides and tetracyclines, two classes of bacteriostatic protein synthesis inhibitors (PSIs), actually kill several gut microbe species and can therefore be classified as bactericidal. Further, in some cases, we observed that PSIs cause unexpected cell shape defects, including lysis (Maier*, Goemans*, Nature, 2021). Our first objective is to understand the molecular mechanism(s) that underline(s) the phenotypical heterogeneity of these different bacterial strains and species after antibiotic treatment.

Understanding how diverse bacterial responses to antibiotics affect communities

Exposure to antibiotics affects the composition and diversity of our gut microbial community, which is associated with short- and long-term health problems. Most of the available information on how antibiotics affect our gut microbiota comes from studies using top-down approaches (cohorts or in vivo studies) which typically provide association-based results. In a recent study (Maier*, Goemans*, Nature, 2021), we probed the direct impact of antibiotics on isolated gut microbes, and observed that different species and even strains exhibit very distinct behaviors after treatment with the same antibiotic. Our second objective is to understand how different phenotypical responses by diverse species or strains to an antibiotic impacts the composition of both synthetic (de novo assembled) or ex-vivo (stool-derived) communities.

Understanding how diverse bacterial responses to antibiotics impacts the development of antibiotic resistance

Efficiently reducing the pace of resistance emergence is crucial; hence, there is a need to elucidate the paths by which such resistance mechanisms naturally occur. The typical methods used to detect and understand antibiotic resistance are either based on the analysis of metagenomics datasets, where the goal is to detect known resistance elements in microbiomes, or on experimental evolution experiments, that mostly focus on model strains and common pathogens. Our third objective is to understand how resistance develops in gut microbes and how it is impacted by species/strain diversity.

Prof. Camille Goemans
​School of Life Sciences - Global Health Institute
Station 19   
CH-1015 Lausanne
​​Camille Goemans- Copyright © 2023