Microbial attachment, modes

The increased resistance of bacteria to antibiotic therapy is a growing concern for doctors and medical officials worldwide. In the last two decades bacteria have developed resistance to almost all the commercially available antibiotics and the number of new antibiotics expected to enter the market is limited. One of the modes by which bacteria exert this resistance is their ability to develop biofilms. Biofilms are bacterial communities encased in a hydrated polymeric matrix. Biofilm development is known to follow a series of complex but discrete and well-regulated steps (Fig. 4.1) (1) microbial attachment to the surface, (2) growth and aggregation of cells into microcolonies, (3) maturation, and (4) dissemination of progeny cells for new colony formalion (87,88). 

In recent years, it has become obvious that the biofilm mode of growth is associated with a specific expression of genes and altered growth rates. To take into consideration the adoption of characteristic biofilm phenotypes by planktonic bacteria, a modern definition of a biofilm has been given by Donlan and Costerton (2002), who described a biofilm as a microbially derived sessile community characterized by cells that are irreversibly attached to a substratum or interface or to each other, are embedded in a matrix of EPS that they have produced, and exhibit an altered phenotype with respect to growth rate and gene transcription . 

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