Bacterial cooperation in multispecies biofilms associated to food production devices

Målgruppe:Biology, Bioinformatics, Molecular Biomedicine
Niveau:Bachelor, Masters

Bacteria cause many serious and sometimes lethal human infections. A significant route of entrance of bacteria into the human body is through food contaminated with pathogenic bacteria. Some food-borne pathogens contaminate the food-processing environment and colonize this together with commensal bacteria, and several species, including pathogens, have been isolated from food production devices.

The contamination of food production devices is likely to be caused by bacterial biofilm formation on these. In a biofilm, bacteria are enclosed in a self-produced polymeric matrix and more protected from disinfectants and antimicrobial agents than their planktonic counterparts. Therefore, bacterial biofilms on equipment may be hard to eradicate.

It has been observed that the protective effect of biofilms may be further enhanced in multispecies biofilms due to various interactions including conjugation. The presence of some species provides a protective effect on other species and may shield them from inactivating compounds. Therefore, species incapable of biofilm formation by themselves may be present in multispecies biofilms, which is of particular interest – and concern – with respect to pathogenic bacteria.

The main aim of this project is to identify the characteristics and prevalence of bacterial cooperation in association to biofilm formation of isolates from food processing environments. Screening of combinations of multiple species from bacterial strain collections will provide information on the prevalence of synergetic bacterial interactions. By use of species-specific detection techniques (qualitative PCR or similar), species dynamics including identification of the species important for the observed synergy will be identified. The ability of the multispecies biofilm to support growth of relevant bacterial pathogens associated to food contamination may also be explored under different growth conditions.

M. Burmølle, J. Webb, D. Rao, L. H. Hansen, S. J. Sørensen and S. Kjelleberg (2006). Enhanced biofilm formation and increased resistance to antimicrobial agents and bacterial invasion are caused by synergistic interactions in multispecies biofilms. Applied and Environmental Microbiology, 72: 3916-23.

Supervisors: Mette Burmølle:
                      Søren J Sørensen:
                      - and relevant co-supervisors

Keywords:Multispecies biofilms, Food contamination
Vejleder(e): Søren J. Sørensen og Mette Burmølle