Biofilmes

JOURNAL OF BACTERIOLOGY, May 2000, p. 2675–2679 0021-9193/00/$04.00 0 Copyright © 2000, American Society for Microbiology. All Rights Reserved.

Vol. 182, No. 10

MINIREVIEW
Biofilm, City of Microbes
PAULA WATNICK1
AND

ROBERTO KOLTER2*

Infectious Disease Unit, Massachusetts General Hospital, Boston, Massachusetts 02114,1 and Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 021152 In most natural environments, association with a surface in a structure known as a biofilm is the prevailing microbial lifestyle. Surface association is an efficient means of lingering in a favorable microenvironment rather than being swept away by the current. Taken to the extreme, we may view the planktonic or free-swimming microbial phase primarily as a mechanism for translocation from one surface to another. Genetic studies of single-species biofilms have shown that they form in multiple steps (46), require intercellular signalling (7), and demonstrate a profile of gene transcription that is distinct from that of planktonic cells (35). From this perspective, biofilm formation may be viewed as a developmental process that shares some of the features of other bacterial developmental processes such as sporulation of gram-positive bacteria (9), fruiting body formation in Myxococcus xanthus (33, 40, 44), and stalked-cell formation by Caulobacter crescentus (13, 19, 24, 37, 48). In natural environments, however, the biofilm is almost invariably a multispecies microbial community harboring bacteria that stay and leave with purpose, share their genetic material at high rates, and fill distinct niches within the biofilm. Thus, the natural biofilm is less like a highly developed organism and more like a complex, highly differentiated, multicultural community much like our own city. There are several steps that we must take to optimize our lives in a city. The first is to choose the city in which we will live, then we must select the neighborhood