Use of a Quartz Crystal Microbalance To Investigate the Antiadhesive Potential of N -Acetyl- l -Cysteine

Abstract

The reduction of bacterial biofilm formation on stainless steel surfaces by N-acetyl-L-cysteine (NAC) is attributed to effects on bacterial growth and polysaccharide production, as well as an increase in the wettability of steel surfaces. In this report, we show that NAC-coated stainless steel and polystyrene surfaces affect both the initial adhesion of Bacillus cereus and Bacillus subtilis and the viscoelastic properties of the interaction between the adhered bacteria and the surface. A quartz crystal microbalance with dissipation was shown to be a powerful and sensitive technique for investigating changes in the applied NAC coating for initial cell surface interactions of bacteria. The kinetics of frequency and dissipation shifts were dependent on the bacteria, the life cycle stage of the bacteria, and the surface. We found that exponentially grown cells gave rise to a positive frequency shift as long as their cell surface hydrophobicity was zero. Furthermore, when the characteristics of binding between the cell and the surface for different growth phases were compared, the rigidity increased from exponentially grown cells to starved cells. There was a trend in which an increase in the viscoelastic properties of the interaction, caused by the NAC coating on stainless steel, resulted in a reduction in irreversibly adhered cells. Interestingly, for B. cereus that adhered to polystyrene, the viscoelastic properties decreased, while there was a reduction in adhered cells, regardless of the life cycle stage. Altogether, NAC coating on surfaces was often effective and could both decrease the initial adhesion and increase the detachment of adhered cells and spores. The most effective reduction was found for B. cereus spores, for which the decrease was caused by a combination of these two parameters.Bacteria commonly adhere to a surface and are part of a complex biofilm. Since the growth of biofilms causes enormous economic losses and health problems in industrial systems like food and paper production, huge efforts are made to solve this problem. The adhesion of bacteria to surfaces is a complex interplay of physical, chemical, and biological factors (5), and there are large variations in the adhesion behaviors of different bacteria and also for different life cycle stages of one strain (41). It is very important to consider these differences when antiadhesion coatings are developed. It is generally thought that bacterial adhesion is preceded by the adsorption of a conditioning layer of molecules that influence adhesion of bacteria to surfaces (43). A good antiadhesion coating should form a conditioning film that prevents adhesion and has a low cohesive strength, making a weak bond between the biofilm and the surface (6). One such agent may be N-acetyl-L-cysteine (NAC). NAC is commonly used in medical treatment of chronic bronchitis and cancer (38,46) and is one of the smallest drug molecules in use (30). Moreover, we recently demonstrated that NAC affects several processes that are important for bacterial biofilm fo...

Activity of some Mucolytics Against Bacterial Adherence to Mammalian Cells

“…These findings agrees with that of Zheng et al [11] who observed by electron microscope a fine, granular, electrondense, ruthenium red-positive layer on the surface of pharyngeal epithelial cells; this layer was absent on cell surfaces treated with mucoregulating drugs; they owed the antiadherent effect of some mucolytics to the disappearance of such molecules. However, our findings are consistent with those of Olofsson et al [34] who attributed the antiadherent activity of the mucolytic agent N-acetyl cysteine to reduction of microbial exopolysaccharide production. Taken together, the findings of the present study open up a new possibility of interfering with bacterial adhesiveness and its resulting pathogenicity by agents devoid of antibacterial activity.…”

Critical review on biofilm methods

“…Non-rigid binding leads to energy dissipation, which can be recorded simultaneously by QCM with dissipation monitoring (QCM-D) (Rodahl et al, 1995). This technique has been used in a wide range of adhesion studies (Olofsson et al, 2005;Otto et al, 1999;Otto & Silhavy, 2002).…”

In Vitro Activity and Durability of a Combination of an Antibiofilm and an Antibiotic against Vascular Catheter Colonization

“…NAC also adversely affects bacterial growth and polysaccharide production and disrupts disulfide bonds in mucus, reducing the viscosity of secretions. These properties may contribute to the prevention and disruption of biofilm around different polymeric and metallic surfaces (9,(19)(20)(21). Not only does NAC diminish the formation of biofilm by common pathogens (19,22,23), it also possesses some in vitro intrinsic antimicrobial activity against both Gram-positive and Gram-negative bacteria (24).…”

“…Cell surface proteins and polysaccharide production by bacterial cells reportedly contribute to the formation of biofilm that can then protect pathogens by impeding both the penetration of antibiotics and the function of phagocytic immune cells, thus hindering the ability to combat colonizing pathogens (7)(8)(9).…”