Biofilm antimicrobial susceptibility through an experimental evolutionary lens

Abstract

Experimental evolution experiments in which bacterial populations are repeatedly exposed to an antimicrobial treatment, and examination of the genotype and phenotype of the resulting evolved bacteria, can help shed light on mechanisms behind reduced susceptibility. In this review we present an overview of why it is important to include biofilms in experimental evolution, which approaches are available to study experimental evolution in biofilms and what experimental evolution has taught us about tolerance and resistance in biofilms. Finally, we present an emerging consensus view on biofilm antimicrobial susceptibility supported by data obtained during experimental evolution studies.

Biofilms preserve the transmissibility of a multi-drug resistance plasmid

“…These biofilm features allow bacteria to access more fitness peaks in rugged adaptive landscapes. This can result in evolutionary outcomes that may not be observed in planktonic populations that routinely experience strong selective sweeps [40][41][42] . Previously we showed that under antibiotic selection, evolution in biofilms results in a higher diversity of plasmid persistence phenotypes as compared to planktonic populations 43 .…”

All-electrical antibiotic susceptibility and resistance profiling of electrogenic Pseudomonas aeruginosa

“…The pellet was resuspended in a new LB medium and diluted to prepare three samples with 0.1, 0.5, and 1.0 OD 600 . Antibiotic-resistant P. aeruginosa was obtained by repeatedly exposing the bacteria to low concentrations of each antibiotic, GEM, CIP, and AMP, 32 and their resistance was confirmed by the disk diffusion test (Fig. S3 †).…”

“…This in vitro experimental evolution of bacteria to antibiotics has been commonly used to identify the mechanisms of antibiotic resistance. 32,33…”

Biofilms preserve the transmissibility of a multi-drug resistance plasmid

“…These biofilm features allow bacteria to access more fitness peaks in rugged adaptive landscapes. This can result in evolutionary outcomes that may not be observed in planktonic populations that routinely experience strong selective sweeps 40–42 . Previously we showed that under antibiotic selection, evolution in biofilms results in a higher diversity of plasmid persistence phenotypes as compared to planktonic populations 43 .…”

“…These biofilm features allow bacteria to access more fitness peaks in rugged adaptive landscapes. This can result in evolutionary outcomes that may not be observed in planktonic populations that routinely experience strong selective sweeps [40][41][42] .…”