Bacterial Adhesion Forces with Substratum Surfaces and the Susceptibility of Biofilms to Antibiotics

Biofilms causing biomaterial-associated infection resist antibiotic treatment and usually necessitate the replacement of infected implants. Here we relate bacterial adhesion forces and the antibiotic susceptibility of biofilms on uncoated and polymer brush-coated silicone rubber. Nine strains of Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa adhered more weakly to brush-coated silicone rubber (0.05 0.03 to0.51 0.62 nN) than to uncoated silicone rubber (1.05 0.46 to5.1 1.3 nN). Biofilms of weakly adhering organisms on polymer brush coatings remained in a planktonic state, susceptible to gentamicin, unlike biofilms formed on uncoated silicone rubber. Biomaterial-associated infections (BAI) remain the numberone cause of failure of biomaterial implants or devices despite the development of various strategies to control BAI during im-plantation, like, e.g., modern, ventilated operating theaters and impermeable personnel clothing (14). Microbial adhesion is con-sidered to be the onset of BAI and can lead to the formation of a biofilm, inwhichmicroorganisms embed themselves in a complex matrix of extracellular polymeric substances (EPS), which pro-vides protection against antibiotic treatment and the host im-mune system (5, 7). Surfacemodifications can significantly reduc