Bacterial colonization of surfaces in flowing systems: methods and analysis

Surfaces in flowing systems are subject to colonization by bacteria. Adsorbed bacteria are a potential source of contamination for any material that contacts the surface, a consideration of importance in pure-water systems. This article describes an experimental strategy for studying initial events in bacterial colonization of surfaces. The experimental goal is to identify surface features that affect the rate and pattern of bacterial adsorption. Greater understanding of these factors could lead to improved control of bacterial adsorption and therefore of process stream contamination. Several quantitative theories for bacterial adsorption have been proposed by others. These theories discriminate between two types of bacterial adsorption: physical adsorption, and chemisorption or adhesion. Physical adsorption is a reversible or equilibrium adsorption involving primary physical forces. Chemisorption is generally irreversible and is the result of short range forces, including chemical bonds, dipole interactions, and hydrophobic bonding. The objective of this work is to uncover empirical relationships between bacterial adsorption locations and physical/chemical surface characteristics. In order to arrive at an empirical description, novel procedures for viewing the colonization process and quantifying the data were devised. This article describes the methodology and presents some preliminary results.