Cumulative effects of multiple stressors on enrichment of genes involved in antibiotic resistance and virulence in biofilm microbial communities

Microbial communities form biofilms in various environments, where they often are exposed to a variety of stressors, which all contribute to the total selective pressure posed on the communities. To survive in these environments, bacteria need to maximize their competitive ability.

Many of the genes contributing to improved competitive ability under stress are virulence factors (VF) or are involved in antibiotic resistance (AR), both of which also have important impacts on infections caused by biofilm-forming bacteria.

However, there is limited knowledge regarding how the simultaneous presence of multiple stressors affects selection processes in biofilms.

This is a great limitation as biofilms in nature are being populated by a variety of different species and are affected simultaneously by various stressors (physical, chemical or biological).

This project will investigate the responses of microbial biofilm communities of different complexity to environmentally relevant levels of individual and combined stress factors.

Particularly, we will focus on the spread of antibiotic resistance genes (ARGs) and VFs between bacterial cells in biofilms.

The project will generate knowledge about the involvement of mobile genetic elements in the stress response, as well as changes to metabolic pathways and biofilm structure.

Understanding the mechanisms for spreading VFs and ARGs in microbial biofilms is important for limiting their ability to spread to human and animal pathogens.