Triclosan Exposure Increases Triclosan Resistance and Influences Taxonomic Composition of Benthic Bacterial Communities

Abstract

Triclosan (TCS) is a broad-spectrum antimicrobial compound that is incorporated into numerous consumer products. TCS has been detected in aquatic ecosystems across the U.S., raising concern about its potential ecological effects. We conducted a field survey and an artificial stream experiment to assess effects of TCS on benthic bacterial communities. Field sampling indicated that TCS concentrations in stream sediments increased with degree of urbanization. There was significant correlation between sediment TCS concentration and the proportion of cultivable benthic bacteria that were resistant to TCS, demonstrating that the levels of TCS present in these streams was affecting the native communities. An artificial stream experiment confirmed that TCS exposure could trigger increases in TCS resistance within cultivable benthic bacteria, and pyrosequencing analysis indicated that TCS resulted in decreased benthic bacterial diversity and shifts in bacterial community composition. One notable change was a 6-fold increase in the relative abundance of cyanobacterial sequences and a dramatic die-off of algae within the artificial streams. Selection of cyanobacteria over algae could have significant implications for higher trophic levels within streams. Finally, there were no observed effects of TCS on bacterial abundance or respiration rates, suggesting that bacterial density and function were highly resilient to TCS exposure.

Sorption and degradation of triclosan in sediments and its effect on microbes

“…4) might be bacterial species that can utilize TCS as carbon source. Drury et al (2013) reported that TCS exposure could trigger increasing TCS resistance with benthic bacteria and decreased benthic bacterial diversity. The similarity coefficient in UPGMA clustering among treatments and control basically declined with the increase of TCS concentrations in the sediments, indicating that the effects of TCS on bacterial community increased with TCS concentrations.…”

Strategies to Prevent Healthcare-Associated Infections through Hand Hygiene

“…187 Furthermore, recent studies suggest that triclosan exposure can lead to resistance, particularly for Pseudomonas aeruginosa. 164,165 Finally, a 2014 study found that the presence of triclosan in the nasal cavities of healthy adults was associated with S. aureus nasal colonization, suggesting that the impact of triclosan on the microbiome is potentially important and warrants further investigation. 166 …”

Partitioning and Degradation of Triclosan and Formation of Methyl-Triclosan in Water-Sediment Systems

“…The 96-h half maximal effective concentration (EC50) and 96-h no observed effect concentration (NOEC) for Scenedesmus were 1.4 and 0.69 μg L −1 , respectively, and the 96-h median lethal concentration (LC50) for Pimephales promelas and Lepomis macrochirus were 260 and 370 μg L −1 , respectively (Orvos et al 2002). Exposure to TCS might increase antimicrobial resistance and lead to crossresistance to antibiotics (Drury et al 2013;Schweizer 2001). TCS can significantly elevate the vitellogenin mRNA expression of mature male western mosquitofish, suggesting that TCS has the potential to act as an endocrine disruptor (Raut and Angus 2010).…”