Use of a modified Robbins device to directly compare the adhesion ofStaphylococcus epidermidisRP62A to surfaces

Abstract

C .J . L I NT ON , A. SH E RR IF F AN D M . R. MI L LA R. 1999.Staphylococcus epidermidis is a frequent cause of infection associated with the use of biomedical devices. Flow cell studies of the interaction between bacteria and surfaces do not generally allow direct comparison of different materials using the same bacterial suspension. The use of a modified Robbins Device (MRD) to compare the adhesion to different surfaces of Staph. epidermidis RP62A grown in continuous culture was investigated. Adhesion to glass was compared with siliconized glass, plasma-conditioned glass, titanium, stainless steel and Teflon. Attachment to siliconized glass was also compared with glass under differing ionic strength, and divalent cation concentrations. Both the differences in numbers adhering and changes in adhesion (slope) through the MRD were compared. There was a trend towards higher numbers adhering to the discs at the in-flow end of the MRD than at the outflow end, probably reflecting depletion of adherent bacteria in the interacting stream. Adhesion of Staph. epidermidis RP62A to siliconized glass and Teflon was reduced when compared to glass with increasing flow rates. Adhesion to stainless steel was not affected by flow rate and titanium gave a different slope of adhesion through the MRD when compared with glass, suggesting an interaction with different sub-populations within the interacting stream. Differences between siliconized glass and glass at flow rates of 300 ml h −1 were abolished by the addition of calcium or EDTA and reduced by the addition of magnesium. Increasing ionic strength reduced the statistical significance of the differences between glass and siliconized glass. Pre-conditioning of glass with pooled human plasma reduced adhesion compared with untreated glass and again gave a different slope to glass. The MRD linked to a chemostat can be used to compare directly bacterial adhesion to potential biomaterials. Variable depletion of the interacting stream should be taken into account in the interpretation of results. Divalent cation concentration, substrate properties and flow rate were important determinants of the comparative adhesion of Staph. epidermidis RP62A to surfaces.

Antimicrobial Efficacy of Two Surface Barrier Discharges with Air Plasma against In Vitro Biofilms

“…The used biofilm model with incubation times of 48 h at 37°C and early replacement of medium showed optimal results for stable and standardized biofilms in previous experiments. The used test microorganisms Pseudomonas aeruginosa SG81 and Staphylococcus epidermidis RP62A are often used for biofilm analyses and tests [40], [41], [42], [43], [44]. They are relevant biofilm forming pathogens in chronic wounds or device related infections [29], [45].…”

Interaction of Staphylococcus epidermidis with endothelial cells in vitro

“…and strain 35984 (RP62A) was obtained from the American Type Culture Collection. Both were clinical isolates, produce bio®lm, and have been well characterized [3, 15,18,20,21,22,26,35]. Bacterial stock cultures were maintained on tryptic soy agar (TSA; Difco, Becton Dickinson and Co., Sparks, Md.)…”

Spatial and Temporal Variations in Chitinolytic Gene Expression and Bacterial Biomass Production during Chitin Degradation

“…However, a study evaluating the effect of shear stress on the adhesion of Staphylococcus epidermidis to a variety of materials including glass, siliconized glass, plasma-conditioned glass, titanium, stainless steel, and Teflon suggested that shear stresses ranging from 0.2 to 1.0 pN m Ϫ2 had little effect on the detachment rate of the surface-colonizing bacteria (32). Thus, the shear stress of 0.004 pN m Ϫ2 calculated for cells of S91 attached to surfaces exposed to flowing seawater in the present study likely represents a negligible force for these bacteria.…”