Influence of Surface Properties on the Adhesion of Staphylococcus epidermidis to Acrylic and Silicone

Abstract

The aim of the present study was to compare the ability of eight Staphylococcus epidermidis strains to adhere to acrylic and silicone, two polymers normally used in medical devices manufacture. Furthermore, it was tried to correlate that with the surface properties of substrata and cells. Therefore, hydrophobicity and surface tension components were calculated through contact angle measurements. Surface roughness of substrata was also assessed by atomic force microscopy (AFM). No relationship was found between microbial surface hydrophobicity and adhesion capability. Nevertheless, Staphylococcus epidermidis IE214 showed very unique adhesion behaviour, with cells highly aggregated between them, which is a consequence of their specific surface features. All strains, determined as being hydrophilic, adhered at a higher extent to silicone than to acrylic, most likely due to its more hydrophobic character and higher roughness. This demonstrates the importance of biomaterial surface characteristics for bacterial adhesion.

Biofilm formation of Brazilian meticillin-resistant Staphylococcus aureus strains: prevalence of biofilm determinants and clonal profiles

“…This fact is corroborated by previous studies (Cerca et al, 2005;Sousa et al, 2009) and suggests that other cell surface factors, such as bacterial adhesins, can contribute to the initial adhesion process. However, when the evaluation was carried out according to the SCCmec type, strains harbouring SCCmec types III and IV were more weakly hydrophilic and adhered better than SCCmecII strains.…”

“…The analysis by SCCmec type showed that the higher the c + component values, the higher the numbers of adhered cells. The surfaces of polystyrene and polymers used in the manufacture of medical devices, such as acrylic and silicone, have electron donor features (Sousa et al, 2009). Increased interactions between electron-donor groups of the substrata and electron-acceptor groups of cells may explain this result.…”

“…Hydrophobicity parameters of bacterial cell surface were determined through the sessile drop contact angle technique, using an automated contact angle device (OCA 15 Plus; Dataphysics), as described previously (Sousa et al, 2009), with some modifications. Briefly, a 20 ml suspension of S. aureus cells, adjusted to a concentration of approximately 1|10 9 cells ml 21 in saline solution (NaCl, 0.9 % w/v), was deposited onto a 0.45 mm cellulose filter (Pall Life Sciences), previously wetted with 10 ml of distilled water.…”

The potential of photo-deposited silver coatings on Foley catheters to prevent urinary tract infections

“…Silicone is widely used as inert biomaterial for urinary devices [26]; however, silicone is more hydrophobic and rougher than acrylic and, thus presents a surface more easily able to be colonised by common human-associated microorganisms such as Staphylococcus epidermidis [43].…”

Preparation, properties, and antibacterial behavior of a novel cellulose derivative containing lactam groups

“…In fact, bacterial adhesion depends on surface properties, including roughness, charge, hydrophobicity, and chemical composition, the hydrophobicity and charge of the bacterial envelope and other surface structures. 36 Bacteria with a hydrophobic exterior will adhere preferentially to hydrophobic substrates, whereas bacteria with hydrophilic surfaces favor hydrophilic materials. 37 The E. coli bacteria used in this study present a predominantly negatively charged, hydrophilic surface composed of lipopolysaccharides and outer membrane proteins, whereas S. aureus, although possessing a negatively-charged surface composed of peptidoglycan, techoic acids, and surface proteins, is radically different in character.…”