Development of novel strategies for inhibition of bacterial biofilms

Abstract

A biofilm is a three-dimensional structure of microorganism aggregates enclosed in an extracellular matrix. The microorganism produces the matrix enclosed itself. The biofilm matrix provides structural integrity and protection to microbes. In the natural conditions, biofilms are the predominant form of microbial life. Bacteria can form biofilm on any surface including biotic and abiotic. Biofilms cause many bacterial infections in the human body such as dental plaque, urinary tract infections, infective endocarditis, otitis media, and other chronic infections. Streptococcus mutans is the agent of dental caries in the human oral cavity. S. mutans can adhere to the enamel salivary pellicle and other bacteria present in dental plaque. Though normally present in healthy oral cavity, an increase in carbohydrate uptake (sucrose) increases acid production leading to higher aciduric S. mutans in a niche. Sucrose is used for glucan formation, which causes enhanced adherence of S. mutans. This disturbs homeostasis and forms caries. Though physical and chemical methods are employed for biofilm removal, they are not fully effective. Probiotics and nanoparticles have emerged as novel antibiofilm agents that counteract antimicrobial resistance in biofilms. Among probiotics Lactobacillus has shown exceptional potential in oral health, inhibiting oral biofilms and antimicrobial against oral pathogenic microorganisms. The broad aim of this study is to develop novel anti-biofilm agents. We have characterized Lactobacillus rhamnosus and Lactobacillus plantarum as potential inhibitors of biofilm formation in S. mutans. The cell-free supernatant (CFS) of Lactobacilli showed antibiofilm activity greater than 70%. We have used chromatographic techniques for the separation of the metabolites.Structure newlineelucidation by mass spectrometry and FTIR revealed the presence of Cyclo (-L-Leu-L-Pro) in L. rhamnosus and limazepines in L. plantarum CFS as the active compounds.