Recent perspectives on the molecular basis of biofilm formation by Pseudomonas aeruginosa and approaches for treatment and biofilm dispersal

Abstract

Pseudomonas aeruginosa, a Gram-negative, rod-shaped bacterium causes widespread diseases in humans. This bacterium is frequently related to nosocomial infections such as pneumonia, urinary tract infections (UTIs) and bacteriaemia especially in immunocompromised patients. The current review focuses on the recent perspectives on biofilms formation by these bacteria. Biofilms are communities of microorganisms in which cells stick to each other and often adhere to a surface. These adherent cells are usually embedded within a self-produced matrix of extracellular polymeric substance (EPS). Pel, psl and alg operons present in P. aeruginosa are responsible for the biosynthesis of extracellular polysaccharide which plays an important role in cell surface interactions during biofilm formation. Recent studies suggested that cAMP signalling pathway, quorum-sensing pathway, Gac/Rsm pathway and c-di-GMP signalling pathway are the main mechanism that leads to the biofilm formation. Understanding the bacterial virulence depends on a number of cell-associated and extracellular factors and is very essential for the development of potential drug targets. Thus, the review focuses on the major genes involved in the biofilm formation, the state of art update on the biofilm treatment and the dispersal approaches such as targeting adhesion and maturation, targeting virulence factors and other strategies such as small molecule-based inhibitors, phytochemicals, bacteriophage therapy, photodynamic therapy, antimicrobial peptides and natural therapies and vaccines to curtail the biofilm formation by P. aeruginosa.

Characterization of Ocular Clinical Isolates of Pseudomonas aeruginosa from Non-Contact Lens Related Keratitis Patients from South India

“…In agreement with this, we found that out of the seven strains which were multi-drug resistant, five were exoU positive. Moreover, these MDR isolates formed moderate to strong biofilms which is consistent with association of biofilm formation with antibiotic resistance reported previously [19]. Swarming has also been associated with increased antibiotic resistance [12].…”

“…Pseudomonas spp. are also known to form biofilms that prevent the penetration of antibiotics contributing to its virulence and are notoriously difficult to eradicate [19]. LadS, a calcium-responsive kinase is required for biofilm formation and is responsible for the swirtch in acute-chronic Pseudomonas infection [20,21].…”

Antibiofilm potential of purified environmental bacteriophage preparations against early stage Pseudomonas aeruginosa biofilms

“…; Skariyachan et al . ). Thus, a biofilm provides P. aeruginosa a protective mode of growth, where individual bacteria can reproduce while circumventing external stresses.…”

“…Bacteria in a biofilm display many different features from their planktonic counterparts. These structured and aggregated bacterial communities are known to be notorious for their resistance to a variety of antibiotics and the action of host defences (Singh et al 2017;Skariyachan et al 2018).…”

Functional Characterization of c-di-GMP Signaling-Related Genes in the Probiotic Lactobacillus acidophilus

“…These GGDEF or EAL domains, in tandem with other signaling domains and located in the cytoplasm or cytomembranes, precisely regulate local intracellular c-di-GMP concentrations by responding to diverse upstream activating signals. C-di-GMP regulates a variety of physiological processes, including cell-cell interactions (Matsuyama et al, 2016; Lin C. S. et al, 2017), biofilm formation and dispersal (Ha and O'Toole, 2015; Skariyachan et al, 2018), cell motility (Orr and Lee, 2016), and the responses to a variety of external stimulation, such as oxygen (Burns et al, 2016), nitric oxide (Rinaldo et al, 2018), and light (Blain-Hartung et al, 2017). The c-di-GMP signaling pathway is present in many Gram-negative bacteria but is less reported in Gram-positive bacteria (Purcell and Tamayo, 2016).…”