Antibiotics promoting oxidative stress inhibit formation of Escherichia coli biofilm via indole signalling

Res Microbiol. 2010 Dec;161(10):847-53. doi: 10.1016/j.resmic.2010.09.012. Epub 2010 Sep 22.


Recent studies have revealed that antibiotics can promote the formation of reactive oxygen species which contribute to cell death. In this study, we report that five different antibiotics known to stimulate production of reactive oxygen species inhibited growth of Escherichia coli biofilm. We demonstrated that supression of biofilm formation was mainly a consequence of the increase in the extracellular concentration of indole, a signal molecule which suppresses growth of bacterial biofilm. Indole production was enhanced under antibiotic-mediated oxidative stress due to overexpression of tryptophanase (TnaA), which catalyzes synthesis of indole. We found that DMSO (dimethyl sulfoxide), a hydrogen peroxide scavenger, or the lack of trypthophanase, which catalyzes production of indole, partly restored formation of E. coli biofilm in the presence of antibiotics. In conclusion, these findings confirmed that antibiotics which promote formation of ROS (reactive oxygen species) can inhibit development of E. coli biofilm in an indole-dependent process.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • Biofilms / drug effects*
  • Biofilms / growth & development*
  • Dimethyl Sulfoxide / metabolism
  • Escherichia coli / drug effects*
  • Escherichia coli / growth & development
  • Escherichia coli / physiology
  • Free Radical Scavengers / metabolism
  • Gene Expression Profiling
  • Indoles / metabolism*
  • Oxidative Stress*
  • Reactive Oxygen Species / metabolism
  • Signal Transduction*
  • Tryptophanase / biosynthesis


  • Anti-Bacterial Agents
  • Free Radical Scavengers
  • Indoles
  • Reactive Oxygen Species
  • indole
  • Tryptophanase
  • Dimethyl Sulfoxide