Strategies for combating bacterial biofilms: A focus on anti-biofilm agents and their mechanisms of action

Abstract

Biofilm refers to the complex, sessile communities of microbes found either attached to a surface or buried firmly in an extracellular matrix as aggregates. The biofilm matrix surrounding bacteria makes them tolerant to harsh conditions and resistant to antibacterial treatments. Moreover, the biofilms are responsible for causing a broad range of chronic diseases and due to the emergence of antibiotic resistance in bacteria it has really become difficult to treat them with efficacy. Furthermore, the antibiotics available till date are ineffective for treating these biofilm related infections due to their higher values of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), which may result in in-vivo toxicity. Hence, it is critically important to design or screen anti-biofilm molecules that can effectively minimize and eradicate biofilm related infections. In the present article, we have highlighted the mechanism of biofilm formation with reference to different models and various methods used for biofilm detection. A major focus has been put on various anti-biofilm molecules discovered or tested till date which may include herbal active compounds, chelating agents, peptide antibiotics, lantibiotics and synthetic chemical compounds along with their structures, mechanism of action and their respective MICs, MBCs, minimum biofilm inhibitory concentrations (MBICs) as well as the half maximal inhibitory concentration (IC50) values available in the literature so far. Different mode of action of anti biofilm molecules addressed here are inhibition via interference in the quorum sensing pathways, adhesion mechanism, disruption of extracellular DNA, protein, lipopolysaccharides, exopolysaccharides and secondary messengers involved in various signaling pathways. From this study, we conclude that the molecules considered here might be used to treat biofilm-associated infections after significant structural modifications, thereby investigating its effective delivery in the host. It should also be ensured that minimum effective concentration of these molecules must be capable of eradicating biofilm infections with maximum potency without posing any adverse side effects on the host.

Polyvinylpyrrolidone-Capped Silver Nanoparticle Inhibits Infection of Carbapenem-Resistant Strain of Acinetobacter baumannii in the Human Pulmonary Epithelial Cell

“…Therefore, it is a high time to develop an alternative drug against carbapenem-resistant strain of A. baumannii . There are different approaches including herbal-based (5, 20, 21), nanomaterial-based (12, 22) and combination therapy (23–29), which have been tried recently against A. baumannii and few of them have shown very promising results.…”

Comparative mechanism based study on disinfectants against multidrug‐resistant Acinetobacter baumannii

“…[4][5][6][7][8][9][10][11][12][13][14] Hospital-acquired infections are associated with high mortality and morbidity rates 15,16 ; hence, their prevention and cure are urgently needed. [4][5][6][7][8][9][10][11][12][13][14] Hospital-acquired infections are associated with high mortality and morbidity rates 15,16 ; hence, their prevention and cure are urgently needed.…”

Molecular insight into the therapeutic potential of phytoconstituents targeting protein conformation and their expression

“…Current antimicrobial drugs become ineffective due to different acquiring resistance by the bacteria such as antibiotic hydrolyzing enzymes (Tiwari et al, 2012a;Moganty, 2013, 2014;Tiwari et al, 2012b), modified target proteins (Vashist et al, 2011), change in permeability (Vashist et al, 2010), up-regulated metabolisms (Tiwari and Rajeswari, 2013;Tiwari et al, 2012c) and MDR efflux pump systems (Djeussi et al, 2013;, biofilm formation (Roy et al, 2018;Tiwari et al, 2018b). Hence novel antibacterial compounds are urgently needed with new bacterial targets.…”