Influence of polymerized siloxane coating on growth and biofilm formation of aerobic grown nosocomial bacteria

Abstract

A recent study showed that polymerized siloxane (PDMS) coating of biomaterials like polycarbonate, stainless steel or glass results in a hydrophobic and positively charged surface, which is known to be advantageous for cell adhesion. However, when Escherichia coli and Staphylococcus epidermidis were cultured on PDMS coated materials for one hour, this resulted in a significant decrease of bacterial adherence compared to non-coated materials. The study therefore aimed at investigating antimicrobial effects of PDMS. We used nosocomial aerobic grown bacteria S. epidermidis, Pseudomonas aeruginosa, E. coli and the biofilm formation model organism Bacillus subtilis, which were exposed to PDMS in a planktonic culture assay and additionally while biofilm formation. PDMS had a significant impact on the growth of these bacteria in both culture assays. In planktonic culture, PDMS exposition resulted in a decreased growth of all bacteria tested, which was strongly species specific. Biofilm culture in contrast caused an increased growth of E. coli and P. aeruginosa, while growth of S. epidermidis and B. subtilis was decreased. However, these results are based on tests of single species biofilms. Previous to practical application it is necessary to confirm these results by tests in which different bacterial species are able to interact like in natural biofilms resulting in modified bacterial growth behavior and toxin resistance.

Comparative effect of seven prophylactic locks to prevent biofilm biomass and viability in intravenous catheters

“…Overall, it appears that after exposure of intravenous catheters to a variety of interventions and the same density of E. coli and S. epidermidis over the same period of time, the E. coli biofilm was several times more plentiful than the S. epidermidis biofilm, producing highly significant differences even at the extremes of the sensitivity analyses. This observation, affecting both biofilm biomass and viability, was also found in a study of biofilms involving polystyrene wells, 11 although another study using polystyrene wells 12 found that biofilm biomass was greater with S. epidermidis than E. coli. The discrepancies between studies may be due to methodological differences.…”

Biosynthesis enhancement of tropodithietic acid (TDA) antibacterial compound through biofilm formation by marine bacteria Phaeobacter inhibens on micro-structured polymer surfaces

“…The effect of surface energy on biolm adhesion is debateable and other factors may play a larger role. 31,32 In a more recent study by Gupta et al, the inuences of uid shear stress and surface roughness of Ti surfaces for attachment and retention of Staphylococcus aureus aggregates were investigated. 33 In this study, of relevance for orthopaedic implants, the structures consisted of machined parallel grooves and ridges with depths and pitches in the hundred mm range.…”