Microbial Biofilms: Microbes in Social Mode

Abstract

Biofilm is a community of microorganisms embedded in extracellular polymeric substances. Organisms in their biofilm form get many advantages over their planktonic counterparts, making them prefer to exist as biofilm. Biofilm formation involves adhesion of microbes on surfaces, followed by maturation stage which is controlled by quorum sensing (QS). Organisms present in biofilm can be 10-1000 times more resistant to antimicrobials compared to their planktonic stage. This may be due to incomplete penetration of antibiotics into the biofilm, slow growth rate of organisms in biofilm, or certain phenotypic changes. Biofilm forming ability of microorganisms has been a source of problems for human health, industry, and agriculture. Natural products including plant extracts, and quorum sensing inhibitors seem to be good alternatives of conventional antibiotics against biofilms. Biofilm forming microbes can be exploited for beneficial applications viz. waste water treatment, N2 fixation, oil degradation, and heavy metal sequestration. This review describes salient features of microbial biofilms, quorum sensing and drugresistance in biofilms, problems caused by biofilms, their potential applications, and methods available for their study.