Bacterial Biofilms: A Common Cause of Persistent Infections

Abstract

Bacteria that attach to surfaces aggregate in a hydrated polymeric matrix of their own synthesis to form biofilms. Formation of these sessile communities and their inherent resistance to antimicrobial agents are at the root of many persistent and chronic bacterial infections. Studies of biofilms have revealed differentiated, structured groups of cells with community properties. Recent advances in our understanding of the genetic and molecular basis of bacterial community behavior point to therapeutic targets that may provide a means for the control of biofilm infections.

Two-component signal transduction systems in oral bacteria

“…pH, temperature, moist, oxygen tension), as well as exposure to diverse host defence factors [1,2]. Dental biofilms contribute to robust microbial communities organized in a complex extracellular matrix that not only provides a structural scaffold but also protects the biofilm organisms from host and exogenous antimicrobial functions [3,4]. As in most biofilms [5], the composition and structure of the extracellular matrix of dental biofilms are dynamically modulated by the colonizing bacteria in response to local biophysical conditions and the availability of substrates that support its synthesis and other metabolic functions [6].…”

The Limitations of In Vitro Experimentation in Understanding Biofilms and Chronic Infection

“…When PMNs fail to eradicate an infection, it is most likely because a biofilm has been established. In the biofilm state, the enclosing matrix of extracellular substances is capable of protecting underlying cells from the immune system, such as PMN phagocytosis [22,23]. In addition to this, biofilms are capable of suppressing the antimicrobial action of PMNs through the production of various virulence factors [19,24].…”

“…In the case of CF, chronic biofilm infections have been known to persist in the airways for over 30 years. Therefore, chronic infections are an ever increasing problem due to their recalcitrance towards extensive antibiotic treatment regimes and persistence under sustained attack from the host's innate and adaptive immune response systems [10,14].…”

Efficacy of 7‐benzyloxyindole and other halogenated indoles to inhibit Candida albicans biofilm and hyphal formation

“…Pathogenic bacteria and fungi are protected by this three‐dimensional matrix, which confers them with high tolerance to antimicrobials. (Costerton et al ., 1999; Davey and O'Toole G, 2000) . Candida albicans is an opportunistic fungal pathogen and causes systemic infections predominantly by contaminating implant devices such as pacemakers, endotracheal tubes, contact lenses, penile implants, intrauterine devices and catheters (Ramage et al ., 2005; Sardi et al ., 2013).…”