Triclosan changes community composition and selects for specific bacterial taxa in marine periphyton biofilms in low nanomolar concentrations

Abstract

The antibacterial agent Triclosan (TCS) is a ubiquitous environmental contaminant due to its widespread use. Sensitivity to TCS varies substantially among eu-and pro-karyotic species and its risk for the marine environment remains to be better elucidated. In particular, the effects that TCS causes on marine microbial communities are largely unknown. In this study we therefore used 16S amplicon rDNA sequencing to investigate TCS effects on the bacterial composition in marine periphyton communities that developed under long-term exposure to different TCS concentrations. Exposure to TCS resulted in clear changes in bacterial composition already at concentrations of 1 to 3.16 nM. We conclude that TCS affects the structure of the bacterial part of periphyton communities at concentrations that actually occur in the marine environment. Sensitive taxa, whose abundance decreased significantly with increasing TCS concentrations, include the Rhodobiaceae and Rhodobacteraceae families of Alphaproteobacteria, and unidentified members of the Candidate division Parcubacteria. Tolerant taxa, whose abundance increased significantly with higher TCS concentrations, include the families Erythrobacteraceae (Alphaproteobacteria), Flavobacteriaceae (Bacteroidetes), Bdellovibrionaceae (Deltaproteobacteria), several families of Gammaproteobacteria, and members of the Candidate phylum Gracilibacteria. Our results demonstrate the variability of TCS sensitivity among bacteria, and that TCS can change marine bacterial composition at concentrations that have been detected in the marine environment.

Repeated introduction of micropollutants enhances microbial succession despite stable degradation patterns

“…Those taxa may have affected micropollutant degradation either directly or indirectly, such as by providing enzymatic repertoires to other community members that enabled degradation, including interspecies interactions [63,64]. Actinobacteria, Alphaproteobacteria, and Bacteroidetes made up the majority of the sensitive taxa; their associations with TCS transformation were previously reported [65,66].…”

Environmental biofilms versus POCIS: efficiency to highlight environmental presence of pharmaceuticals and their effect on biofilm microbiome

“…Numerous studies have reported negative effects of PhC on microbial biofilm structure and functioning. These are commonly expressed by decrease in biomass and diversity, decline in photosynthetic activity and bacterial enzymatic activity, increase in bacterial mortality rates, suppression of algal growth and microbial respiration and others (Corcoll et al, 2014; Drury et al, 2013; Eriksson et al, 2020; Guo et al, 2016; Proia et al, 2013b, 2013a; Rosi-Marshall et al, 2015, 2013; Serra-Compte et al, 2018; Tlili et al, 2020). It is therefore important to understand better the fate of these emerging contaminants in the different environmental compartments and their impact on aquatic organisms.…”

An Overview of the Impact of Pharmaceuticals on Aquatic Microbial Communities

“…However, some studies provide insight into the effects of pharmaceutical ECs in microbial communities of different water bodies. Martin et al [ 84 ] studied the effects of triclosan, at environmentally relevant concentrations, on marine periphyton biofilms, determining that its exposure results in changes in their bacterial composition. With increasing triclosan concentrations, Rhodobiaceae and Rhodobacteraceae families of Alphaproteobacteria and unidentified members of the candidate division Parcubacteria decreased their abundance, while families Erythrobacteraceae ( Alphaproteobacteria ), Flavobacteriaceae ( Bacteroidetes ), Bdellovibrionaceae ( Deltaproteobacteria ), several families of Gammaproteobacteria , and members of the candidate phylum Gracilibacteria increased in abundance.…”