Clinical Escherichia coli: From Biofilm Formation to New Antibiofilm Strategies

Abstract

Escherichia coli is one of the species most frequently involved in biofilm-related diseases, being especially important in urinary tract infections, causing relapses or chronic infections. Compared to their planktonic analogues, biofilms confer to the bacteria the capacity to be up to 1000-fold more resistant to antibiotics and to evade the action of the host’s immune system. For this reason, biofilm-related infections are very difficult to treat. To develop new strategies against biofilms, it is important to know the mechanisms involved in their formation. In this review, the different steps of biofilm formation in E. coli, the mechanisms of tolerance to antimicrobials and new compounds and strategies to combat biofilms are discussed.

Efficacy of Antimicrobial Photodynamic Therapy Mediated by Photosensitizers Conjugated with Inorganic Nanoparticles: Systematic Review and Meta-Analysis

“…The biofilm formation of E. coli occurs in followed phases; reversible attachment, irreversible attachment, maturation, and dispersion [ 48 ]. In particular, the maturation phase is characterized by the final architecture and arrangement of the biofilm conferred by the matrix formation [ 49 ]. The matrix provides biofilm stability, promotes intercellular interaction, and enables the transport of nutrients and waste through the biofilms.…”

Anti-Biofilm Effect of Bacteriophages and Antibiotics against Uropathogenic Escherichia coli

“…Studies show that the ability to create a biofilm depends on various factors. One of them is that biofilm formation is genetically encoded and is one of the defense mechanisms that ensure resistance [ 14 , 15 ]. Many studies indicate that the mechanical and physical–chemical properties of the biofilm matrix reduce or delay the penetration of many compounds, including antibacterial agents.…”

Analysis of the Metabolic Response of Planktonic Cells and Biofilms of Klebsiella pneumoniae to Sublethal Disinfection with Sodium Hypochlorite Measured by NMR

“…The development of biofilm at a surface results from physical, chemical, and microbial processes, including pH, hydrodynamics, osmolarity, presence of specific ions, nutrients, and factors derived from the biotic environment [ 8 ]. The transition from the planktonic to the biofilm state involves the interaction of several proteins and regulatory systems, such as 3′,5′-cyclic diguanylic acid (c-di-GMP), two-component signaling systems (TCS), the RcsCDB regulator, and quorum sensing (QS) [ 9 ]. Other factors contributing to K. pneumoniae biofilm formation include, among others, the presence of a polysaccharide capsule, lipopolysaccharide (LPS), fimbriae, pili, iron metabolism, and the presence of other bacterial species [ 10 , 11 ].…”

“…They can survive the presence of disinfectants, shear forces, thermal stress, and predators [ 4 ]. The resistance mechanisms of biofilms include the physical barrier provided by the extracellular matrix, which decreases antimicrobial penetration; alteration of the outer membrane; the production of enzymes that transform biocides into non-toxic forms; persister cells; efflux pumps; high heterogeneity in metabolism and growth rates; horizontal gene transfer [ 9 , 12 ]; and adaptive mutagenesis [ 13 ].…”