Title

Triclosan Enriches for Dehalococcoides-like Chloroflexi in Anaerobic Soil at Environmentally Relevant Concentrations

Document Type

Article

Language

eng

Format of Original

5 p.

Publication Date

2007

Publisher

Oxford University Press

Source Publication

FEMS Microbiology Letters

Source ISSN

0378-1097

Original Item ID

doi: 10.1111/1574-6968.12153

Abstract

Triclosan is an antimicrobial agent that is discharged to soils with land-applied wastewater biosolids, is persistent under anaerobic conditions, and yet its impact on anaerobic microbial communities in soils is largely unknown. We hypothesized that triclosan enriches for Dehalococcoides-like Chloroflexi because these bacteria respire organochlorides and are likely less sensitive, relative to other bacteria, to the antimicrobial effects of triclosan. Triplicate anaerobic soil microcosms were seeded with agricultural soil, which was not previously exposed to triclosan, and were amended with 1 mg kg−1 of triclosan. Triplicate control microcosms did not receive triclosan, and the experiment was run for 618 days. The overall bacterial community (assessed by automated ribosomal intergenic spacer analysis and denaturing gradient gel electrophoresis) was not impacted by triclosan; however, the abundance of Dehalococcoides-like Chloroflexi 16S rRNA genes (determined by qPCR) increased 20-fold with triclosan amendment compared with a fivefold increase without triclosan. This work demonstrates that triclosan impacts anaerobic soil communities at environmentally relevant levels.

Comments

FEMS Microbiology Letters, Vol. 344, No. 1 (2007): 48-52. DOI.