Understanding the Influence of Mammalian Epithelial Cells on Staphylococcus aureus Quorum Sensing in Flow Conditions

Abstract

Staphylococcus aureus (S. aureus) is a major cause of many nosocomial infections. Over the last 70 years, different strains of the bacteria have evolved resistance to several different antibiotics, making continued development of new antibiotics necessary for treatment. As such, other potential therapeutics have been explored, including suppressing the ability of S. aureus to perform quorum sensing (QS). During quorum sensing, S. aureus synchronize expression of the genes that ultimately contribute to their pathogenicity through the production and secretion of extracellular protein signals that other cells detect once the population reaches a high cell density. Despite the role QS plays in the context of human infection, the patterns of S. aureus QS in in vivo conditions containing mammalian host cells is not fully understood. This study investigated whether interactions between S. aureus and human intestinal epithelial cells influenced patterns in bacterial growth and QS output. Using fluorescence microscopy and co-cultures of cells in microfluidic systems, we did not observe any distinct differences in trends of bacterial growth nor QS output between co-cultures and monocultures of bacteria under flow conditions. A deeper understanding of S. aureus QS in a mammalian host context could have major implications on public health and the treatment of potentially fatal bacterial infections. Further studies will be critical to further characterize the patterns of QS spatially and temporally during infection.