Evaluation of different detection methods of biofilm formation in Staphylococcus aureus

Med Microbiol Immunol. 2002 Oct;191(2):101-6. doi: 10.1007/s00430-002-0124-3. Epub 2002 Jun 29.


The icaADBC gene locus of Staphylococcus aureus and its polysaccharide intercellular adhesin (PIA/PNSG) were recently identified, but biofilm formation has rarely been detected in vitro. In this study we evaluated a tissue culture plate (TCP) assay and a tube test, as well as Congo red agar, using the two basic media trypticase soy broth (TSB) and brain heart infusion (BHI) broth with different sugar supplements for detection of biofilm formation in 128 ica-positive S. aureus isolates. Of the S. aureus strains, 57.1% displayed a biofilm-positive phenotype under optimized conditions in the TCP test. The tube test correlated well with the TCP test for strongly biofilm-producing strains, whereas weak producers were not safely discriminated from biofilm-negative strains. Screening on Congo red agar displayed a strong correlation with the TCP and the tube test for only 3.8%, and is therefore not recommended for investigation of biofilm formation in S. aureus.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Agar / metabolism
  • Biofilms / growth & development*
  • Caseins
  • Congo Red / metabolism
  • Culture Media / classification
  • Culture Techniques / methods
  • N-Acetylglucosaminyltransferases
  • Polymerase Chain Reaction / methods
  • Protein Hydrolysates
  • Staphylococcus aureus / genetics
  • Staphylococcus aureus / isolation & purification
  • Staphylococcus aureus / physiology*
  • Time Factors


  • Caseins
  • Culture Media
  • Protein Hydrolysates
  • trypticase-soy broth
  • Congo Red
  • Agar
  • N-Acetylglucosaminyltransferases
  • N-acetyllactosaminide beta-1,6-N-acetylglucosaminyltransferase