The Deposition of Streptococcus sanguis NCTC 7868 from a Flowing Suspension

Abstract

Measurements were made of the rates at which continuously cultured Streptococcus sanguis NCTC 7868 cells accumulated on the inside surfaces of narrow glass capillaries from suspensions of the bacteria flowing down the capillaries at different velocities. Initially, the rate of accumulation of bacteria on the clean walls of the capillary was rapid. The deposition rate decreased with time, however, resulting in a saturation coverage of the glass surface which was considerably less than a monolayer. Multilayer coverage of the tube surface by bacteria was only achieved when fresh nutrient was pumped over deposited cells. This was attributed to cell growth. Although theoretical considerations of the deposition of small particles on to the walls of a tube suggest that the initial deposition rate should increase with flow rate, this was not the case with cells grown at dilution rates of 0.2 and 0.5 h-1. It is suggested that this can be explained by a polymer bridging mechanism of attachment.

Adhesion and biofilm development on suspended carriers in airlift reactors: Hydrodynamic conditions versus surface characteristics

“…Reduced adhesion or sticking efficiency at high shear rates has been reported before (Duddridge et al, 1982;Lau and Liu, 1993;Powel and Slater, 1983;Rutter and Leech, 1980). Rutter and Leech (1980) suggested that it can be explained by a polymer bridging mechanism for adhesion.…”

“…Reduced adhesion or sticking efficiency at high shear rates has been reported before (Duddridge et al, 1982;Lau and Liu, 1993;Powel and Slater, 1983;Rutter and Leech, 1980). Rutter and Leech (1980) suggested that it can be explained by a polymer bridging mechanism for adhesion. After a relatively weak physical adsorption, during which lateral displacement of the cells over a homogenous surface does not in- fluence the interactions, the cells are anchored to the carrier surface by bridges or extracellular polymers.…”

“…However, other processes are also involved and might ultimately have greater influence on biofilm formation. For example, increased levels of liquid shear have been shown to reduce bacterial adhesion (Duddridge et al, 1982;Lau and Liu, 1993;Powel and Slater, 1983;Rutter and Leech, 1980). In full-scale biofilm reactors like fluidized-bed and airlift reactors, hydrodynamic conditions differ greatly from those applied in most adhesion assays.…”

Physicochemical Interactions of the Substratum, Microorganisms, and the Fluid Phase

“…Cell multiplication due to growth should also be eliminated or minimized. Techniques using small glass capillaries have been developed by a number of authors (19,22). Generally, the deposition rate of cells to the glass walls of the capillary is much less than the collision rate.…”

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

“…This could result in an increase in adhesion to the surface, as with polystyrene latex beads (Rutter and leach 1980). However, this is not always the case with bacteria as in this study, and with Streptococcus sanguis NCTC 7868, adhering to the walls of glass capillaries (Rutter and Leech 1980). The effect of conditioning of a surface on the adherence of bacteria is difficult to determine.…”