Dual species biofilms: do staphylococci like other bacteria?

Abstract number: p822

Walencka  E., Sadowska  B., Rozalska  B.


Different forms of the interdependencies between microorganisms, like tolerance, interference commensalism or synergism, develop during coexistence of bacteria in the same ecological niche. They also play an important role when multispecies biofilm consisting of both physiologic or/and pathogenic microflora is formed. The aim of the study was to determine the interactions between staphylococci and other bacteria and their influence on dual species biofilm formation.


The interdependencies between Staphylococcus aureus or Staphylococcus epidermidis clinical strains and selected reference or clinical strains of Pseudomonas aeruginosa, Proteus mirabilis, Escherichia coli, Enterococcus faecalis were estimated in different stages of dual species biofilm formation. The influence of bacteriocin-like inhibitory substances (BLIS) produced by coaggregating strains on the growth of S. aureus A3 and S. epidermidis A4c was determined by two-layer plate assay and by dilution assay for bacterial supernatants. The activity of BLIS against bacterial adherence and biofilm formation was estimated using spectrophotometric assay (MTT). The quantitative method using the carriers of biofilm was developed to determine the composition of mixed biofilms.


All bacterial strains used for the study were capable of the biofilm formation with S. aureus and S. epidermidis, however with different intensity. The antagonistic activity of BLIS on the growth, adherence or/and biofilm formation by S. aureus or S. epidermidis was not always correlated with the blocking of coadhesion. The biggest interference during staphylococcal biofilm formation was observed when E. coli and P. aeruginosa strains were used as the second element of this structure.


Understanding of the mechanisms of bacterial interference in mixed species biofilms development and the survival of different microbial species living at the close proximity in the same matrix may help in the proceeding on therapeutic strategies.


Supported by Grant No. 2 PO5A 149 29 from State Committee for Scientific Research.

Session Details

Date: 01/08/2007
Time: 00:00-00:00
Session name: XXIst ISTH Congress
Location: Oxford, UK
Presentation type:
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