Bacterial biofilm: structure, function, and antimicrobial resistance

Abstract

Biofilms are microbial communities attached to surfaces and encased in an extracellular matrix of microbial origin. They represent the predominant form of microbial life. Biofilms are everywhere and can develop on virtually every natural and man-made surface. Biofilms are also ubiquitous in both normal and pathogenic human processes. Biofilm formation has been demonstrated for numerous pathogens and is clearly one of the main strategies for bacterial survival in a variety of sites within the human body. In almost all instances, the biofilm lifestyle helps bacteria survive and persist within the environment. This review discusses the fundamental biology of microbial biofilm and how biofilms impact the pathogenesis of human infections. The different mechanisms involved in the reduced antimicrobial susceptibility of microorganisms in pathogenic biofilms are discussed in detail in this review. Possible approaches that could be explored in the search for new anti-biofilm strategies to eradicate medically relevant biofilms are also presented.

The Formation of Streptococcus mutans Persisters Induced by the Quorum-Sensing Peptide Pheromone Is Affected by the LexA Regulator

“…A major survival mechanism of bacteria is antibiotic tolerance, whereby bacterial cells that have a slower or reduced growth rate become more tolerant toward antibiotic killing (2,3). This reduction in bacterial growth is prominently perceived as one of the main survival mechanisms elicited in bacterial biofilms, by which the slower growth of biofilm cells contributes toward the highly recalcitrant nature of biofilm infections, even in biofilm populations that lack genetically encoded antibiotic resistance markers (4,5).…”

Construction and verification of the transcriptional regulatory response network of Streptococcus mutansupon treatment with the biofilm inhibitor carolacton

“…This is attributed to its ability to form biofilms which are generally difficult or impossible to eradicate by antibiotic therapy because biofilm cells are resistant to antibiotics [1, 2]. …”

Synthesis and functional evaluation of peptide modified poly (lactic-co-glycolic acid) nanoparticles to inhibit porphyromonas gingivalis biofilm formation.

“…8,22 Over 700 different species of bacteria colonize and interact with each other to form dental plaque 14 . In a state of health, the oral cavity is comprised of benign commensals, majorly Actinomyces and streptococci 22 .…”

“…Following initial attachment, adherent bacteria begin to proliferate and form microcolonies 14,31 . Each microcolony acts as an independent community and may contain a variety of bacterial species 31 .…”

“…Bacteria that are located in the center of the microcolony usually live in a strict anaerobic environment, while others at the periphery of the microcolony are exposed to a more aerobic environment 22 . Therefore, a biofilm is a dynamic structure that can provide a range of environments with respect to nutrient and oxygen concentrations and thus may successfully harbor a diverse bacterial population 31 To sustain these bacterial populations, a series of fluid channels exist between microcolonies to provide nutrients and oxygen required for normal bacterial growth and to facilitate outward movement of bacterial metabolites, waste products, and enzymes 14,32,38 . Additionally, each bacterial microcolony uses chemical signals to create a primitive communication system within the biofilm, a perfect niche for bacterial propagation and existence 33,33,34 .…”