Isolation and characterization of biofilm-forming bacteria and associated extracellular polymeric substances from oral cavity

Kirti Jain, Sheetal Parida, Neelam Mangwani, Hirak R. Dash, Surajit Das

Research output: Contribution to journalArticlepeer-review

Abstract

The current work deals with the studies on characterization of two biofilm-forming bacteria isolated from the oral cavity. The major constituent of biofilm other than bacterial cells is the extracellular polymeric substance (EPS) matrix, which is secreted by the bacterial cells themselves. Physical properties of biofilms such as attachment, mechanical strength, antibiotic resistance can be attributed to EPS matrix. Molecular phylogeny confirmed these two isolates as Pseudomonas aeruginosa and Bacillus subtilis. It was observed that cell attachment in both the strains was maximal when xylose was used as the sole carbon source. The EPS characterization result indicated the presence of a macromolecular complex constituting of carbohydrate, protein, lipids and nucleic acids. Test for biofilm formation in the presence of metal salts of iron and zinc showed moderate to high inhibition of biofilm formation. However, calcium, iron and copper have been found to enhance biofilm growth significantly. There was more than 50 % increase in biofilm growth by P. aeruginosa with an increase in calcium concentration up to 80 ppm (Two tailed t-test P<0.05), whereas ≥ 15 % increase in biofilm growth by B. subtilis was observed in the presence of 80 ppm of calcium. However, variations were significant (Two way ANOVA, P<0.01) between different metals in different concentrations. In this study, attempts have been made to examine the effect of different carbon sources and physiological conditions on biofilm growth.

Original languageEnglish (US)
Pages (from-to)1553-1562
Number of pages10
JournalAnnals of Microbiology
Volume63
Issue number4
DOIs
StatePublished - Dec 2013
Externally publishedYes

Keywords

  • Bacillus
  • Biofilms
  • EPS
  • Macromolecules
  • Pseudomonas
  • Xylose

ASJC Scopus subject areas

  • Applied Microbiology and Biotechnology

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