Biofilm susceptibility to metal toxicity

Environ Microbiol. 2004 Dec;6(12):1220-7. doi: 10.1111/j.1462-2920.2004.00656.x.


This study compared bacterial biofilm and planktonic cell susceptibility to metal toxicity by evaluating the minimum inhibitory concentration (MIC), the planktonic minimum bactericidal concentration (MBC), and minimum biofilm eradication concentration (MBEC) using the MBEC device. In total, 17 metal cations and oxyanions, chosen to represent groups VIB to VIA of the periodic table, were each tested on biofilm and planktonic cultures of Escherichia coli JM109, Staphylococcus aureus ATCC 29213, and Pseudomonas aeruginosa ATCC 27853. In contrast to control antibiotic assays, where biofilm cultures were 2 to 64 times less susceptible to killing than logarithmically growing planktonic bacteria, metal compounds killed planktonic and biofilm cultures at the same concentration in the vast majority of combinations. Our data indicate that, under the conditions reported, growth in a biofilm does not provide resistance to bacteria against killing by metal cations or oxyanions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Biofilms / drug effects*
  • Biofilms / growth & development
  • Cations / pharmacology
  • Escherichia coli / drug effects*
  • Escherichia coli / growth & development
  • Metals / pharmacology*
  • Microbial Sensitivity Tests
  • Pseudomonas aeruginosa / drug effects*
  • Pseudomonas aeruginosa / growth & development
  • Staphylococcus aureus / drug effects*
  • Staphylococcus aureus / growth & development


  • Anti-Bacterial Agents
  • Cations
  • Metals