Bacterial biofilms: from the Natural environment to infectious diseases

Abstract

Biofilms are clusters of microorganisms that stick to non-biological surfaces, such as rocks in a stream, as well as to surfaces on plants (roots) or in animals (epithelium). These clusters are often encased in an outer polymer layer that can be produced by the microorganism or by the defensive mechanisms of the colonized host. Biofilm formation is astonishingly widespread in nature and appears very early in the fossil record. Biofilm development also occurs in a vastly diverse range of microorganisms, including those that have changed little over of time. So, biofilm formation seems to be an ancient and fundamental part of the life cycles of many microorganisms and essential for survival in diverse environments. Biofilm formation represents a protected mode of growth that not only allows cells to survive in hostile environments, but also to colonize new niches by dispersal of microorganisms from the microbial clusters. Biofilms are an important, but incompletely understood, form of growth and survival for many bacteria. Recent evidence reveals that biofilms are structurally complex, dynamic systems that have both the characteristics of primitive multicellularly organized organisms and complex ecosystems. In this review, the implications of survival and dispersal mechanisms are discussed in the context of both the natural environment and infectious diseases.