Interactions in multispecies biofilms: do they actually matter?

•Synergistic interactions affect biovolume and functionality of multispecies biofilms. •Properties and functions relevant to human health are altered in multispecies biofilms. •Multispecies biofilms are hot spots for generation of novel genotypes by means of horizontal gene transfer (HGT). •Recent advances in technologies enable omic studies of interactions in multispecies biofilms. The recent focus on complex bacterial communities has led to the recognition of interactions across species boundaries. This is particularly pronounced in multispecies biofilms, where synergistic interactions impact the bacterial distribution and overall biomass produced. Importantly, in a number of settings, the interactions in a multispecies biofilm affect its overall function, physiology, or surroundings, by resulting in enhanced resistance, virulence, or degradation of pollutants, which is of significant importance to human health and activities. The underlying mechanisms causing these synergistic effects are to some extent characterized at the molecular and evolutionary levels, and further exploration is now possible due to the enhanced resolution and higher throughput of available techniques. The recent focus on complex bacterial communities has led to the recognition of interactions across species boundaries. This is particularly pronounced in multispecies biofilms, where synergistic interactions impact the bacterial distribution and overall biomass produced. Importantly, in a number of settings, the interactions in a multispecies biofilm affect its overall function, physiology, or surroundings, by resulting in enhanced resistance, virulence, or degradation of pollutants, which is of significant importance to human health and activities. The underlying mechanisms causing these synergistic effects are to some extent characterized at the molecular and evolutionary levels, and further exploration is now possible due to the enhanced resolution and higher throughput of available techniques. cell–cell attachment through specific components on the cell surface. a social behavior having a negative effect of the receiver of the act. a social behavior having a positive effect on the receiver of the act. bacterial aggregates in suspension, usually in aquatic environments. Involved in degradation of organic material in wastewater treatment plants. transfer of genetic material between organisms through specific mechanisms as opposed to vertical genetic transfer though reproduction. the sum of the fitness obtained through own reproduction (direct fitness) and the indirect fitness gained from enhancing reproduction of relatives. matrix-enclosed cell clusters constituting a biofilm. May be surface attached and separated by water channels, host tissue, etc. the fraction of a bacterial population capable of receiving and maintaining a specific plasmid. a sensory system that enables bacteria to detect population densities and regulate gene expression accordingly. interactions of which the total outcome is functionally different or higher than expected from the individual components.