Mechanisms and Control Strategies of Antibiotic Resistance in Pathological Biofilms

Abstract

Bacterial biofilm is a community of bacteria that are embedded and structured in a self-secreted extracellular matrix. An important clinical-related characteristic of bacterial biofilms is that they are much more resistant to antimicrobial agents than the planktonic cells (up to 1,000 times), which is one of the main causes of antibiotic resistance in clinics. Therefore, infections caused by biofilms are notoriously difficult to eradicate, such as lung infection caused by Pseudomonas aeruginosa in cystic fibrosis patients. Understanding the resistance mechanisms of biofilms will provide direct insights into how we overcome such resistance. In this review, we summarize the characteristics of biofilms and chronic infections associated with bacterial biofilms. We examine the current understanding and research progress on the major mechanisms of antibiotic resistance in biofilms, including quorum sensing. We also discuss the potential strategies that may overcome biofilm-related antibiotic resistance, focusing on targeting biofilm EPSs, blocking quorum sensing signaling, and using recombinant phages.

Keywords: Biofilm; antibiotic resistance mechanisms; control strategies; quorum sensing.

Fig. 1. Structure and life cycle of bacterial biofilms.

(1) Initial surface attachment of planktonic bacteria cells; (2) cell to cell adhesion and biofilm growth; (3) biofilm maturation; and (4) cell detachment and biofilm dispersal. Polysaccharides, nucleic acids, protein and lipids are major components of biofilms. The biofilm form of bacteria is resistant to many environmental insults, including UV light, antibiotics, and salinity. Anti-biofilm methods mentioned in this review are shown, indicated with green arrows at the locations where they act.