Antimicrobial and Antibiofilm N-acetyl-L-cysteine Grafted Siloxane Polymers with Potential for Use in Water Systems

Abstract

Antibiofilm strategies may be based on the prevention of initial bacterial adhesion, the inhibition of biofilm maturation or biofilm eradication. N-acetyl-L-cysteine (NAC), widely used in medical treatments, offers an interesting approach to biofilm destruction. However, many Eubacteria strains are able to enzymatically decompose the NAC molecule. This is the first report on the action of two hybrid materials, NAC-Si-1 and NAC-Si-2, against bacteria isolated from a water environment: Agrobacterium tumefaciens, Aeromonas hydrophila, Citrobacter freundii, Enterobacter soli, Janthinobacterium lividum and Stenotrophomonas maltophilia. The NAC was grafted onto functional siloxane polymers to reduce its availability to bacterial enzymes. The results confirm the bioactivity of NAC. However, the final effect of its action was environment- and strain-dependent. Moreover, all the tested bacterial strains showed the ability to degrade NAC by various metabolic routes. The NAC polymers were less effective bacterial inhibitors than NAC, but more effective at eradicating mature bacterial biofilms.

NO Candida auris: Nitric Oxide in Nanotherapeutics to Combat Emerging Fungal Pathogen Candida auris

“…These effects may be due to the physico-chemical properties of the nanoparticles (e.g., particle size, charge, and surface chemistry) causing disruption in cell-to-cell communication and other cellular processes such as quorum sensing that are involved in biofilm formation [ 31 ]. We have found similar results in our previous studies with different blank particle formulations [ 31 , 41 ], where thiols are known to interact with disulfide bonds and react with extracellular polysaccharides, impairing ECM formation and adhesion of biofilm to surfaces [ 35 , 36 ]. In the blank-np for this experiment, the amines present on the particles may also have contributed to the antimicrobial activity of the particles [ 44 ].…”

“…In the present work, we demonstrate the efficacy of a novel NAC-SNO-np treatment platform against six strains of both planktonic and biofilm forms of C. auris . This nanoparticle formulation releases NO, NAC, and NAC-SNO—All of which have previously demonstrated antimicrobial effects [ 35 , 36 , 37 , 38 ]. Thiol groups from NAC have been shown to exhibit antimicrobial activity through the formation of peroxynitrite [ 39 ].…”

Expression of a Shiga-Like Toxin during Plastic Colonization by Two Multidrug-Resistant Bacteria, Aeromonas hydrophila RIT668 and Citrobacter freundii RIT669, Isolated from Endangered Turtles (Clemmys guttata)

“…Antibiotic-resistant C. freundii strains have been increasing around the world, and extended β-lactamase and plasmid-mediated quinolone resistance have been documented [66,[68][69][70][71][72]. C. freundii strains have been isolated from mixed biofilms from water supply systems, growing along with strains such as Agrobacterium tumefaciens, A. hydrophila, Enterobacter soli and Stenotrophomonas maltophilia [73]. The presence of C. freundii worsens existing Pseudomonas aeruginosa infections in murine models and also likely in patients with co-infection [74].…”

Novel nitric oxide‒generating platform using manuka honey as an anti‐biofilm strategy in chronic rhinosinusitis

“…This effect may be mediated by thiol groups in the blank microparticle, which harbor intrinsic antioxidant and antimicrobial properties. This has been demonstrated in N ‐acetylcysteine, a well‐characterized molecule that, like our blank microparticle, contains thiol groups . Thiols can irreversibly react with the disulfide bonds of key bacterial proteins involved in growth.…”

“…This has been demonstrated in N-acetylcysteine, a well-characterized molecule that, like our blank microparticle, contains thiol groups. 36,37 Thiols can irreversibly react with the disulfide bonds of key bacterial proteins involved in growth. The thiol groups can also react with proteins governing the production of extracellular polysaccharide, thus preventing the production of the biofilm extracellular matrix and impairing the adhesion of biofilms to surfaces and thereby interrupting the biofilm lifecycle.…”