N-Acetyl-l-Cysteine Affects Growth, Extracellular Polysaccharide Production, and Bacterial Biofilm Formation on Solid Surfaces

ABSTRACT N-Acetyl-l-cysteine (NAC) is used in medical treatment of patients with chronic bronchitis. The positive effects of NAC treatment have primarily been attributed to the mucus-dissolving properties of NAC, as well as its ability to decrease biofilm formation, which reduces bacterial infections. Our results suggest that NAC also may be an interesting candidate for use as an agent to reduce and prevent biofilm formation on stainless steel surfaces in environments typical of paper mill plants. Using 10 different bacterial strains isolated from a paper mill, we found that the mode of action of NAC is chemical, as well as biological, in the case of bacterial adhesion to stainless steel surfaces. The initial adhesion of bacteria is dependent on the wettability of the substratum. NAC was shown to bind to stainless steel, increasing the wettability of the surface. Moreover, NAC decreased bacterial adhesion and even detached bacteria that were adhering to stainless steel surfaces. Growth of various bacteria, as monocultures or in a multispecies community, was inhibited at different concentrations of NAC. We also found that there was no detectable degradation of extracellular polysaccharides (EPS) by NAC, indicating that NAC reduced the production of EPS, in most bacteria tested, even at concentrations at which growth was not affected. Altogether, the presence of NAC changes the texture of the biofilm formed and makes NAC an interesting candidate for use as a general inhibitor of formation of bacterial biofilms on stainless steel surfaces.

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Disrupting Irreversible Bacterial Adhesion and Biofilm Formation with an Engineered Enzyme

Applied and Environmental Microbiology ◽

10.1128/aem.00265-21 ◽

2021 ◽

Author(s):

Holly M. Mayton ◽

Sharon L. Walker ◽

Bryan W. Berger

Keyword(s):

Listeria Monocytogenes ◽

Bacterial Adhesion ◽

Biofilm Formation ◽

Glycosyl Hydrolase ◽

Cell Surface Hydrophobicity ◽

Bacterial Biofilm ◽

Enzyme Treatment ◽

E Coli ◽

Initial Adhesion ◽

The Impact

Biofilm formation is often attributed to post-harvest bacteria persistence on fresh produce and food handling surfaces. In this study, a predicted glycosyl hydrolase enzyme was expressed, purified and validated for removal of microbial biofilms from biotic and abiotic surfaces under conditions used for chemical cleaning agents. Crystal violet biofilm staining assays revealed that 0.1 mg/mL of enzyme inhibited up to 41% of biofilm formation by E. coli O157:H7, E. coli 25922, Salmonella Typhimurium, and Listeria monocytogenes. Further, the enzyme was effective at removing mature biofilms, providing a 35% improvement over rinsing with a saline solution alone. Additionally, a parallel-plate flow cell was used to directly observe and quantify the impact of enzyme rinses on E. coli O157:H7 cells adhered to spinach leaf surfaces. The presence of 1 mg/L enzyme resulted in nearly 6 times greater detachment rate coefficients than a DI water rinse, while the total cells removed from the surface increased from 10% to 25% over the 30 minute rinse time, reversing the initial phases of biofilm formation. Enzyme treatment of all 4 cell types resulted in significantly reduced cell surface hydrophobicity, and collapse of negatively stained E. coli 25922 cells imaged by electron microscopy, suggesting potential polysaccharide surface modification of enzyme-treated bacteria. Collectively, these results point to the broad substrate specificity and robustness of the enzyme to different types of biofilm stages, solution conditions and pathogen biofilm types, and may be useful as a method for removal or inhibition of bacterial biofilm formation. IMPORTANCE In this study, the ability of an engineered enzyme to reduce bacterial adhesion and biofilm formation of several foodborne pathogens was demonstrated, representing a promising option for enhancing or replacing chlorine and other chemical sanitizers in food processing applications. Specifically, significant reductions of the pathogens Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes biofilms are observed, as well as reduction in initial adhesion. Enzymes have the added benefits of being green, sustainable alternatives to chemical sanitizers, as well as having minimal impact on food properties, in contrast with many alternative antimicrobial options such as bleach that aim to minimize food safety risks.

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Fire Ant Venom Alkaloids Inhibit Biofilm Formation

Toxins ◽

10.3390/toxins11070420 ◽

2019 ◽

Vol 11 (7) ◽

pp. 420 ◽

Cited By ~ 4

Author(s):

Danielle Bruno de Carvalho ◽

Eduardo Gonçalves Paterson Fox ◽

Diogo Gama dos Santos ◽

Joab Sampaio de Sousa ◽

Denise Maria Guimarães Freire ◽

...

Keyword(s):

Stainless Steel ◽

Bacterial Adhesion ◽

Solenopsis Invicta ◽

Biofilm Formation ◽

Food Industry ◽

Fire Ant ◽

Ant Venom ◽

Steel Surfaces ◽

Adhesion Inhibition ◽

Medical Health

Biofilm formation on exposed surfaces is a serious issue for the food industry and medical health facilities. There are many proposed strategies to delay, reduce, or even eliminate biofilm formation on surfaces. The present study focuses on the applicability of fire ant venom alkaloids (aka ‘solenopsins’, from Solenopsis invicta) tested on polystyrene and stainless steel surfaces relative to the adhesion and biofilm-formation by the bacterium Pseudomonas fluorescens. Conditioning with solenopsins demonstrates significant reduction of bacterial adhesion. Inhibition rates were 62.7% on polystyrene and 59.0% on stainless steel surfaces. In addition, solenopsins drastically reduced cell populations already growing on conditioned surfaces. Contrary to assumptions by previous authors, solenopsins tested negative for amphipathic properties, thus understanding the mechanisms behind the observed effects still relies on further investigation.

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

Applied and Environmental Microbiology ◽

10.1128/aem.71.5.2705-2712.2005 ◽

2005 ◽

Vol 71 (5) ◽

pp. 2705-2712 ◽

Cited By ~ 37

Author(s):

Ann-Cathrin Olofsson ◽

Malte Hermansson ◽

Hans Elwing

Keyword(s):

Stainless Steel ◽

Life Cycle ◽

Cell Surface ◽

Quartz Crystal Microbalance ◽

Viscoelastic Properties ◽

Quartz Crystal ◽

Life Cycle Stage ◽

Bacterial Biofilm ◽

Initial Adhesion ◽

Steel Surfaces

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.

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The Effectiveness of Nafion-Coated Stainless Steel Surfaces for Inhibiting Bacillus Subtilis Biofilm Formation

Applied Sciences ◽

10.3390/app10145001 ◽

2020 ◽

Vol 10 (14) ◽

pp. 5001

Author(s):

Lijuan Zhong ◽

Yibo Song ◽

Shufeng Zhou

Keyword(s):

Stainless Steel ◽

Bacillus Subtilis ◽

Bacterial Adhesion ◽

Biofilm Formation ◽

Stainless Steel Surface ◽

Electrostatic Effects ◽

Uncoated Surface ◽

Coated Surface ◽

Steel Surfaces

Stainless steel is one of most commonly used materials in the world; however, biofilms on the surfaces of stainless steel cause many serious problems. In order to find effective methods of reducing bacterial adhesion to stainless steel, and to investigate the role of electrostatic effects during the formation of biofilms, this study used a stainless steel surface that was negatively charged by being coated with Nafion which was terminated by sulfonic groups. The results showed that the roughness of stainless steel discs coated with 1% Nafion was similar to an uncoated surface; however the hydrophobicity increased, and the Nafion-coated surface reduced the adhesion of Bacillus subtilis by 75% compared with uncoated surfaces. Therefore, a facile way to acquire antibacterial stainless steel was found, and it is proved that electrostatic effects have a significant influence on the formation of biofilms.

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Bond Strengthening in Oral Bacterial Adhesion to Salivary Conditioning Films

Applied and Environmental Microbiology ◽

10.1128/aem.01119-08 ◽

2008 ◽

Vol 74 (17) ◽

pp. 5511-5515 ◽

Cited By ~ 40

Author(s):

Henny C. van der Mei ◽

Minie Rustema-Abbing ◽

Joop de Vries ◽

Henk J. Busscher

Keyword(s):

Bacterial Adhesion ◽

Biofilm Formation ◽

Specific Interactions ◽

Adhesion Forces ◽

Bacterial Strains ◽

Bacterial Interactions ◽

Initial Adhesion ◽

Conditioning Film ◽

Interacting Surfaces ◽

Conditioning Films

ABSTRACT Transition from reversible to irreversible bacterial adhesion is a highly relevant but poorly understood step in initial biofilm formation. We hypothesize that in oral biofilm formation, irreversible adhesion is caused by bond strengthening due to specific bacterial interactions with salivary conditioning films. Here, we compared the initial adhesion of six oral bacterial strains to salivary conditioning films with their adhesion to a bovine serum albumin (BSA) coating and related their adhesion to the strengthening of the binding forces measured with bacteria-coated atomic force microscopy cantilevers. All strains adhered in higher numbers to salivary conditioning films than to BSA coatings, and specific bacterial interactions with salivary conditioning films were accompanied by stronger initial adhesion forces. Bond strengthening occurred on a time scale of several tens of seconds and was slower for actinomyces than for streptococci. Nonspecific interactions between bacteria and BSA coatings strengthened twofold faster than their specific interactions with salivary conditioning films, likely because specific interactions require a closer approach of interacting surfaces with the removal of interfacial water and a more extensive rearrangement of surface structures. After bond strengthening, bacterial adhesion forces with a salivary conditioning film remained stronger than those with BSA coatings.

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Impact of Marine Bacterial Adhesion on the Physico-chemical Properties of Stainless Steel Surfaces

Asian Journal of Scientific Research ◽

10.3923/ajsr.2020.50.57 ◽

2019 ◽

Vol 13 (1) ◽

pp. 50-57

Author(s):

Douaae Ou-yahia ◽

Kawtar Fikri-Benb ◽

Yassir Lekbach ◽

Fadoua Bennouna ◽

Hassan Barkai ◽

...

Keyword(s):

Stainless Steel ◽

Bacterial Adhesion ◽

Chemical Properties ◽

Physico Chemical ◽

Steel Surfaces

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Nanoengineered Superhydrophobic Surfaces to Prevent Adhesion of Listeria monocytogenes for Improved Food Safety

Transactions of the ASABE ◽

10.13031/trans.13934 ◽

2020 ◽

Vol 63 (5) ◽

pp. 1401-1407

Author(s):

Bog Eum Lee ◽

Youngsang You ◽

Won Choi ◽

Eun-mi Hong ◽

Marisa M. Wall ◽

...

Keyword(s):

Stainless Steel ◽

Listeria Monocytogenes ◽

Biofilm Formation ◽

Electrochemical Etching ◽

Contact Angles ◽

Bacterial Attachment ◽

Superhydrophobic Surfaces ◽

List Type ◽

Ptfe Film ◽

Steel Surfaces

HighlightsNanoporous superhydrophobic surfaces were fabricated using electrochemical etching and Teflon coating.Adhesion of Listeria monocytogenes to the nanoengineered stainless steel surfaces was reduced.Self-cleanable food-contact surfaces prevent bacterial attachment and subsequent biofilm formation.Abstract. Bacterial attachment on solid surfaces and subsequent biofilm formation is a significant problem in the food industry. Superhydrophobic surfaces have potential to prevent bacterial adhesion by minimizing the contact area between bacterial cells and the surface. In this study, stainless steel-based superhydrophobic surfaces were fabricated by manipulating nanostructures with electrochemical etching and polytetrafluoroethylene (PTFE) film. The formation of nanostructures on stainless steel surfaces was characterized by field emission scanning electron microscopy (FESEM). The stainless steel surfaces etched at 10 V for 5 min and at 10 V for 10 min with PTFE deposition resulted in average water contact angles of 154° ±4° with pore diameters of 50 nm. In addition, adhesion of Listeria monocytogenes was decreased by up to 99% compared to the bare substrate. These findings demonstrate the potential for the development of antibacterial surfaces by combining nanoporous patterns with PTFE films. Keywords: Electrochemical etching, PTFE, Nanoengineered surface, L. monocytogenes, Superhydrophobic.

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Direct and Indirect Evidence of the Microbially Induced Pitting Corrosion of Steel Structures in Humid Environments

Coatings ◽

10.3390/coatings10100983 ◽

2020 ◽

Vol 10 (10) ◽

pp. 983

Author(s):

Jingzhong Zhou ◽

Kuoteng Sun ◽

Songqiang Huang ◽

Xuemin He ◽

Zhaowei Hu ◽

...

Keyword(s):

Stainless Steel ◽

Pitting Corrosion ◽

Biofilm Formation ◽

Indirect Evidence ◽

Steel Structures ◽

Electrochemical Analysis ◽

Bacterial Biofilm ◽

Direct Role ◽

Severe Problem ◽

Corrosion Of Steel

Corrosion is a severe problem for steel structures in humid environments. In particular, humidity usually triggers the surface adhesion of microorganisms, leading to microbiologically induced corrosion. This study aims to explore the effect of bacterial biofilm formation on the pitting corrosion of stainless steel. This research uses electrochemical methods to obtain indirect evidence of the pitting corrosion of steel. In addition, in order to obtain direct evidence of the pitting corrosion of stainless steel, field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) were used to characterize the dimensional morphology of the stainless steel after pitting. It was shown that the bacterial adhesion increased with the pH and temperature, which significantly increased the surface roughness of the stainless steel. Electrochemical analysis revealed that the formation of biofilm greatly destroyed the oxide film of 304 SS and accelerated the corrosion of stainless steel by forming an oxygen concentration battery. SEM and AFM analyses showed cracks and dislocations on the surface of stainless steel underneath the attached bacteria, which suggested a direct role of biofilm in corrosion induction. The results presented here show that the bacterial biofilm formation on the steel surfaces significantly accelerated the corrosion and affected the pitting corrosion process of the steel structure.

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Biofilm Formation byMycobacterium bovis: Influence of Surface Kind and Temperatures of Sanitizer Treatments on Biofilm Control

BioMed Research International ◽

10.1155/2014/210165 ◽

2014 ◽

Vol 2014 ◽

pp. 1-7 ◽

Cited By ~ 9

Author(s):

Victoria O. Adetunji ◽

Aderemi O. Kehinde ◽

Olayemi K. Bolatito ◽

Jinru Chen

Keyword(s):

Stainless Steel ◽

Ammonium Chloride ◽

Mycobacterium Bovis ◽

Biofilm Formation ◽

Binding Assay ◽

Liver Extract ◽

Hot Water ◽

Solid Surfaces ◽

Pine Oil ◽

Steel Surfaces

Mycobacterium boviscauses classic bovine tuberculosis, a zoonosis which is still a concern in Africa. Biofilm forming ability of twoMycobacterium bovisstrains was assessed on coupons of cement, ceramic, or stainless steel in three different microbiological media at 37°C with agitation for 2, 3, or 4 weeks to determine the medium that promotes biofilm. Biofilm mass accumulated on coupons was treated with 2 sanitizers (sanitizer A (5.5 mg L−1active iodine) and sanitizer B (170.6 g1alkyl dimethylbenzyl ammonium chloride, 78 g−1didecyldimethyl ammonium chloride, 107.25 g L−1glutaraldehyde, 146.25 g L−1isopropanol, and 20 g L−1pine oil) at 28 and 45°C and in hot water at 85°C for 5 min. Residual biofilms on treated coupons were quantified using crystal violet binding assay. The two strains had a similar ability to form biofilms on the three surfaces. More biofilms were developed in media containing 5% liver extract. Biofilm mass increased as incubation time increased till the 3rd week. More biofilms were formed on cement than on ceramic and stainless steel surfaces. Treatment with hot water at 85°C reduced biofilm mass, however, sanitizing treatments at 45°C removed more biofilms than at 28°C. However, neither treatment completely eliminated the biofilms. The choice of processing surface and temperatures used for sanitizing treatments had an impact on biofilm formation and its removal from solid surfaces.

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