Effect of Lactoferrin on Staphylococcus Epidermidis biofilm Development

Lactoferrin was found to significantly reduce Staphylococcus epidermidis biofilm growth in a concentration dependent manner. S. epidermidis is one of the most common causes of nosocomial (hospital-acquired) infections in the US. The primary virulence factor of S. epidermidis is biofilm formation. Bacterial biofilms are surface-adherent communities of bacterial cells encapsulated by a self-produced matrix. Lactoferrin, a protein prevalent throughout the human body, including in blood, human milk, and the tear film, is known to have an antimicrobial effect on planktonic, free-floating S. epidermidis cells by iron chelation and cell wall disruption. However, the antimicrobial effect of lactoferrin on S. epidermidis biofilms is not fully understood. Quantitative image analysis of confocal laser scanning microscopy images was utilized to evaluate the effect of lactoferrin on biofilm development, bacterial cell wall integrity, and biofilm mechanics. Biofilm development was assessed by evaluating biofilm biovolume, height, and porosity. Cell wall integrity was assessed through analysis of the prevalence of cells labeled with propidium iodide. Biofilm mechanics were evaluated using microrheology measurements. Lactoferrin influences S. epidermidis biofilm development in a concentration dependent manner where treatment with higher concentrations of lactoferrin results in shorter, more porous biofilms, an increased prevalence of cells with compromised cell membranes, and biofilms with softer mechanics. Understanding the effect of lactoferrin on S. epidermidis biofilm development is important for developing antibiofilm therapeutics and ultimately reducing the prevalence of nosocomial infections.