Aims

The principal aims of this chapter are to describe:

• the molecular basis of bacterial adhesion

• the range of adhesins produced by bacteria

• the types of bacterial structures involved in adhesion

• the nature of the host receptors for bacterial adhesins

• tissue tropism

• the consequences of adhesion for the bacterium and for the host cell

• the possibility of anti-adhesion approaches as prophylactic or therapeutic measures for bacterial infections

Introduction

The ability of a bacterium to adhere to its host is an often-overlooked aspect of virulence and in this chapter we will consider this crucial first stage in the induction of an infectious disease. It is difficult to understand why adhesion should be given such short shrift by many microbiologists as it is an essential preliminary to any interaction (including one of the most intimate interactions possible, disease) between a bacterium and its host. We would also like to stress that adhesion should not be regarded simply as a somewhat random, serendipitous ‘sticking’ of a bacterium to its host. Rather, the adhesion process is accomplished by highly specific molecular interactions and is accompanied by changes in the phenotype of the bacterium and, when the substratum is cellular, changes in the behaviour of the host cell.

Before we go any further, it is important to consider how we should go about investigating the interactions between bacteria and host cells. Practical bacteriology is traditionally based on the use of a ‘pure culture’ (axenic) of an organism.