Antibacterial surfaces on expanded polytetrafluoroethylene; penicillin attachment

Expanded polytetrafluoroethylene (ePTFE) was chemically modified to retard the growth of Staphylococcus aureus bacteria. This was accomplished by microwave plasma reactions in the presence of maleic anhydride (MA) to create acid functional groups on ePTFE surfaces, followed by esterification reactions with 200 and 600 molecular weight linear polyethylene glycol (PEG). Such surfaces were utilized for further reactions with penicillin (PEN) through etherification reactions to create anti-microbial surfaces. These reactions resulted in surface morphological changes, and spectroscopic analysis using attenuated total reflectance Fourier transform infrared spectroscopy (ATR FT-IR) revealed the formation of ester linkages resulting from reactions between PEN and PEG functionalities. Antibacterial activities were evaluated by a series of experiments where PEN-modified ePTFE specimens were immersed in a liquid aureus culture, and the bacteria growth was quantified by measuring % absorbance of the suspension at 600 nm wavelength. The lowest absorbance was observed for the solution containing PEN-PEG-MA-ePTFE specimens, thus showing highly effective anti-bacterial activity toward gram-positive Staphylococcus aureus bacteria. To our best knowledge, this is the first study that shows PEN-ePTFE surface modifications that are effective against gram-positive aureus bacteria.     

The effectiveness of antibiotic activity of penicillin attached to expanded poly(tetrafluoroethylene) (ePTFE) surfaces: a quantitative assessment

Recent studies identified and established a platform of polymer surface modifications allowing the attachment of penicillin (PEN) to expanded poly(tetrafluoroethylene) (ePTFE) surfaces. The effectiveness of this approach was accomplished by creating surfaces with chemically attached PEN that prevent the proliferation of microbes. In this study, quantitative assessments of PEN effectiveness attached to ePTFE were conducted. Using variable-angle attenuated total reflectance (ATR-FTIR) spectroscopy, the volume concentration changes of PEN were determined as a function of depth from the ePTFE surface. At depths ranging from 0.2 to 1.2 mum from the surface, PEN concentration levels decrease from 8.85 to 3.33 mug/m3. Assessments of concentration levels of the colony forming units (CFUs) of Staphylococcus aureus bacteria as a function of contact time with the penicillin-polyethylene glycol spacer separated by maleic anhydride ePTFE (PEN-PEG-MA-ePTFE) surfaces showed profound effectiveness of PEN in preventing microbial proliferation. Hydrolytic stability of PEN-PEG-MA-ePTFE surfaces revealed that even with a 32% loss of PEN due to the cleavage of the ester linkages between PEN and PEG spacer, antimicrobial activity is still maintained.     

Lipase-catalyzed production of a bioactive fatty amide derivative of 7,10-dihydroxy-8(E)-octadecenoic acid

Enzymatic syntheses of fatty amides are of considerable interest due to their wide ranging industrial applications in detergents, shampoo, cosmetics and surfactant formulations. Amidation reaction of Candida antarctica lipase B (CALB) was investigated for direct amidation of carboxylic acid in organic solvent. CALB-mediated production of a novel secondary amide was carried out by reacting the hydroxy oleic acid derivative, 7,10-dihydroxy-8(E)-octadecenoic acid (DOD), with N-methylethanol amine in organic solvent medium. A single, new product peak corresponding to the secondary amide of DOD (D2AM) was detected by high-performance liquid chromatography and thin-layer chromatography. The production of D2AM was achieved in high yields (95%) after 72 h at 50 degrees C in a CALB-catalyzed reaction that contained 100 IU enzyme activity, 50 mM DOD, and 100 mM N-methylethanol amine in isoamyl alcohol. The new fatty amide D2AM displayed potent antimicrobial activity towards Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative bacteria (Proteus vulgaris and Klebsiella pneumonae). D2AM also exhibited antioxidative activity by its alpha,alpha-diphenyl-beta-picryl-hydrazyl (DPPH) radicals scavenging effects.     

C-terminal amidation of PMAP-23: translocation to the inner membrane of Gram-negative bacteria

PMAP-23 is a member of the cathelicidin family derived from pig myeloid cells and has potent antimicrobial activity. Amidation of the carboxyl terminus (C-terminus) of an antimicrobial peptide generally enhances its structural stability and antimicrobial activity or decreases its cytotoxicity. The aim of the present study was to investigate the effect of amidation on the mode of action in PMAP-23. Irrespective of amidation, PMAP-23 adopts a helix–hinge–helix structure in a membrane-mimetic environment. The antibacterial activities of PMAP-23C, which had a free C-terminus, and PMAP-23N, which had an amidated C-terminus, were similar against Gram-negative bacteria, reflecting a similar ability to neutralize lipopolysaccharide. However, PMAP-23N assumed a perpendicular orientation across the outer to the inner leaflet of the bacterial inner membrane, while PMAP-23C was orientated parallel to the lipid bilayer, as determined by following the blue shift in tryptophan fluorescence, as well as calcein release from liposomes and SYTOX Green uptake assays. These results suggest that N-terminal amidation of PMAP-23 provides structural stability and increases the peptide’s cationic charge, facilitating translocation into the bacterial inner membrane.     

Novel monodisperse PEG-dendrons as new tools for targeted drug delivery: synthesis, characterization and cellular uptake

Dendrimers, dendrons, and hyperbranched polymers are gaining popularity as novel drugs, imaging agents, and drug delivery systems. They present advantages of well-defined molecular weight, multivalent surfaces, and high drug carrying capacity. Moreover, it is emerging that such architectures can display unique endocytic properties. As poly(ethylene glycol) (PEG) is widely used for protein and drug conjugation, the aim of this study was for the first time to synthesize novel, branched PEG-based architectures, to define their cytotoxicity and, via preparation of Oregon green (OG) conjugates define the effect of structure on their cellular uptake. Five PEG-based dendrons were synthesized using monodisperse Fmoc-amino PEG propionic acid (M(w) = 840) as a monomer, and cadaverine, tris(2-aminoethyl)amine or lysine as the branching moieties. These were diamino,bisPEG (M(w) = 1300); triamino,trisPEG (Mw = 1946); tetraamino,tetraPEG (M(w) = 3956); monocarboxy,diamino,bisPEG (M(w) = 1346); and monocarboxy,tetraamino,tetraPEG (M(w) = 3999). These products had NH(2) or both NH(2) and COOH terminal groups and the identity was verified by amino group analysis and ESI-TOF mass spectroscopy. Purity was determined by HPLC. Representative structures were not toxic towards an endothelial-like cell line (ECV304) at concentrations up to 4 mg/mL (over 72 h). At 37 degrees C, all of the OG-labeled PEG dendrons showed progressive uptake by ECV304 cells, but tetraamino,tetraPEG showed the greatest rate of internalization over the first 20 min. Cellular uptake was inhibited at 4 degrees C, and PEG dendron localization to perinuclear vesicles was confirmed by fluorescence microscopy. These well-defined novel architectures have potential for further development as targetable drug delivery systems or tools for construction of structurally defined modified surfaces.     

Dual host-defence functions of SPLUNC2/PSP and synthetic peptides derived from the protein

PSP (parotid secretory protein)/SPLUNC2 (short palate, lung and nasal epithelium clone 2) is expressed in human salivary glands and saliva. The protein exists as an N-glycosylated and non-glycosylated form and both appear to induce agglutination of bacteria, a major antibacterial function for salivary proteins. Both forms of PSP/SPLUNC2 bind LPS (lipopolysaccharide), suggesting that the protein may also play an anti-inflammatory role. Based on the predicted structure of PSP/SPLUNC2 and the location of known antibacterial and anti-inflammatory peptides in BPI (bactericidal/permeability-increasing protein) and LBP (LPS-binding protein), we designed GL13NH2 and GL13K, synthetic peptides that capture these proposed functions of PSP/SPLUNC2. GL13NH3 agglutinates bacteria, leading to increased clearance by macrophages and reduced spread of infection in a plant model. GL13K kills bacteria with a minimal inhibitory concentration of 5-10 μg/ml, kills bacteria in biofilm and retains activity in 150?mM NaCl and 50% saliva. Both peptides block endotoxin action, but only GL13K appears to bind endotoxin. The peptides do not cause haemolysis, haemagglutination in serum, inhibit mammalian cell proliferation or induce an inflammatory response in macrophages. These results suggest that the GL13NH2 and the modified peptide GL13K capture the biological activity of PSP/SPLUNC2 and can serve as lead compounds for the development of novel antimicrobial and anti-inflammatory peptides.     

Protein carboxyl amidation increases the potential extent of protein polyethylene glycol conjugation

Chemical coupling of polyethylene glycol (PEG) to therapeutic proteins reduces their immunogenicity and prolongs their circulating half-life. The limitation of this approach is the number and distribution of sites on proteins available for PEGylation (the N terminus and the -amino group of lysines). To increase the extent of PEGylation, we have developed a method to increase the number of PEGylation sites in a model protein, recombinant methionine alpha,gamma-lyase (recombinant methioninase; rMETase), an enzyme cancer therapeutic cloned from Pseudomonas putida. rMETase was first PEGylated with methoxypolyethylene glycol succinimidyl glutarate-5000 with a molar ratio of PEG:rMETase of 15:1. The carboxyl groups of the initially PEGylated protein were then conjugated with diaminobutane, resulting in carboxyl amidation. This reaction was catalyzed by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide, a water-soluble carbodiimide. The steric hindrance provided by the PEG chains already coupled to the protein prevented cross-linking between rMETase molecules during the carboxyl amidation reaction. The carboxyl-amidated PEGylated rMETase was hyper-PEGylated at a molar ratio of PEG to PEG-rMETase of 60:1. Biochemical analysis indicated that 13 PEG chains were coupled to each subunit of rMETase after hyper-PEGylation compared with 6-8 PEG chains attached to the non-carboxyl-amidated PEG-rMETase. Approximately 15-20% of the non-PEGylated rMETase activity was retained in the hyper-PEGylated molecule. Immunogenicity of the hyper-PEG-rMETase was significantly reduced relative to PEG-rMETase and rMETase. Initial results suggest that hyper-PEGylation may become a new strategy for PEGylation of protein biologics.     

PIII 改性ePTFE 膜对细菌生存状态的影响研究

目的:探讨等离子注入技术(Plasma immersion ion implantation,PⅢ)对膨体聚四氟乙烯(ePTFE)膜改性后表面性能以及对细菌生存状态的影响.方法:采用氧等离子注入技术(PⅢ)对ePTFE膜表面处理,获得改性ePTFE膜,利用扫描电镜(SEM)观察改性ePTFE膜和未处理膜的表面形貌,体外培养变形链球菌,观察改性前后各组膜作体外细菌生存状态变化.结果:与未处理ePTFE膜相比,改性ePTFE膜表面形貌、亲水性发生改变.荧光染色后观察长脉冲组表面的细菌最少;短脉冲组膜表面粘附的细菌密集,形成生物膜;空白组可见少量死菌和活菌粘附于ePTFE膜上.结论:长脉冲PⅢ改性ePTFE膜后有良好的抗细菌粘附能力.     

A high-density poly(ethylene glycol) polymer brush for immobilization on glass-type surfaces.

Label-free heterogeneous phase detection critically depends on the properties of the interfacial layer. We have obtained high-density monomolecular poly(ethylene glycol) (PEG) layers by solvent-free coupling of homo-bifunctional PEGs (2,000 g/mol) at 75 degrees C to silica surfaces silanized with glycidyloxipropyltrimethoxysilane (GOPTS). Characterization by ellipsometry and contact angles revealed that PEG layers up to 3.4 ng/mm2 with low roughness and flexibility were obtained. Specific and non-specific binding at these PEG surfaces was monitored by reflectometric interference spectroscopy (RIfS). No significant non-specific adsorption upon incubation of 1 mg/ml ovalbumin was detectable (< 10 pg/mm2), and 150 pg/mm2 upon incubation of 10% calf serum, less than 10% of the amount adsorbed to the solely silanized surfaces. The terminal functional groups of the PEG layers were utilized to couple ligands and a protein. Specific protein interaction with these immobilized compounds was detected with saturation loadings in the range of protein monolayers (2-4 ng/mm2). The excellent functional properties, the high stability of the layers, the generic and practical coupling procedure and the versatility for immobilizing compounds of very different functionality make these PEG layers very attractive for application in label-free detection with silica or metal-oxide based transducers.     

A facile synthesis of azido-terminated heterobifunctional poly(ethylene glycol)s for "click" conjugation

New azido-terminated heterobifunctional poly(ethylene glycol) (PEG) derivatives having primary amine and carboxyl end groups, (Azide-PEG-NH 2 and Azide-PEG-COOH, respectively) were synthesized with high efficiency. An alpha-allyl-omega-hydroxyl PEG was prepared as the first step to Azide-PEG-X (X = NH 2 and COOH) through the ring-opening polymerization of ethylene oxide (EO) with allyl alcohol as an initiator, followed by two-step modification of the hydroxyl end to an azido group. To introduce primary amino or carboxyl functional groups, amination and carboxylation reactions of the allyl terminal ends was then conducted by a radical addition of thiol compounds. Molecular functionalities of both ends of the PEG derivatives thus prepared were characterized by (1)H, (13)C NMR, and MALDI-TOF MS spectra, validating that the reaction proceeded quantitatively. The terminal azido functionality is available to conjugate various ligands with an alkyne group through the 1,3-dipolar cycloaddition reaction condition ("click chemistry").     

Design and synthesis of self-degradable antibacterial polymers by simultaneous chain- and step-growth radical copolymerization

Self-degradable antimicrobial copolymers bearing cationic side chains and main-chain ester linkages were synthesized using the simultaneous chain- and step-growth radical polymerization of t-butyl acrylate and 3-butenyl 2-chloropropionate, followed by the transformation of t-butyl groups into primary ammonium salts. We prepared a series of copolymers with different structural features in terms of molecular weight, monomer composition, amine functionality, and side chain structures to examine the effect of polymer properties on their antimicrobial and hemolytic activities. The acrylate copolymers containing primary amine side chains displayed moderate antimicrobial activity against E. coli but were relatively hemolytic. The acrylate copolymer with quaternary ammonium groups and the acrylamide copolymers showed low or no antimicrobial and hemolytic activities. An acrylate copolymer with primary amine side chains degraded to lower molecular weight oligomers with lower antimicrobial activity in aqueous solution. This degradation was due to amidation of the ester groups of the polymer chains by the nucleophilic addition of primary amine groups in the side chains resulting in cleavage of the polymer main chain. The degradation mechanism was studied in detail by model reactions between amine compounds and precursor copolymers.     

Suppression of Listeria monocytogenes colonization following adsorption of nisin onto silica surfaces.

Nisin is an antimicrobial peptide proven to be an effective inhibitor of gram-positive bacteria. It is known that nisin can adsorb to various surfaces and still retain much of its original activity (M. A. Daeschel, J. McGuire, and H. Al-Makhlafi, J. Food Prot. 55:731-735, 1992). In this study, nisin films were allowed to form on silanized silica surfaces and then exposed to medium containing Listeria monocytogenes. Representative areas were selected from each surface, and images of resident listeriae were obtained at 4-h intervals for 12 h. During this time, cells on surfaces that had been in contact with a high concentration of nisin (1.0 mg/ml) exhibited no signs of growth and many displayed evidence of cellular deterioration. Surfaces treated with a lower concentration of nisin (0.1 mg/ml) had a smaller degree of inhibition. In contrast, both protein-free surfaces and those with films of heat-inactivated nisin allowed attached L. monocytogenes cells to grow and reproduce. These studies, when repeated with a nisin-resistant strain of L. monocytogenes, resulted in no inhibition of growth on surfaces with adsorbed nisin. The bactericidal effect of adsorbed nisin was also studied with iodonitrotetrazolium violet, a tetrazolium salt, which is reduced to a red formazan crystal by viable bacteria. Crystals were visible in 95% of the cells adhered to control surfaces but were present in less than 20% of the cells on surfaces with adsorbed nisin. These data indicate that adsorbed nisin may have potential for use as a food grade antimicrobial agent on food contact surfaces.     

Ability of cofactors to support peptide amidation is cell-type specific

The ability of various cofactors to substitute for ascorbate in the biosynthesis of alpha-aidated peptides from pro-ACTH/endorphin (PAE) was compared in corticotrope tumor cells (AtT-20) and in primary anterior and intermediate pituitary cultures. In all three systems, ascorbate was the most potent cofactor tested. In AtT-20 cells, dopamine, norepinephrine, epinephrine, dehydroascorbate and dihydro- and tetrahydrobiopterin supported significant alpha-amidation of joining peptide [PAE(77-94)NH2]. In contrast, amidation of joining peptide by primary corticotropes was stimulated only slightly by catecholamines and not by tetrahydrobiopterin. Neither catecholamines nor tetrahydrobiopterin stimulated peptide amidation by melanotropes. The ability of cofactors to support the synthesis of alpha-amidated peptides is cell-type specific.     

Introducing RGD peptides on PHBV films through PEG-containing cross-linkers to improve the biocompatibility

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), a biodegradable polyester, has been a good candidate of biomaterial employed in tissue engineering. However, the PHBV film is hydrophobic and has no recognition sites for cell attachment. In this study, PHBV films are activated by ammonia plasma treatment to produce amino groups on the surface, followed by sequential reactions with a heterobifunctional cross-linker containing a segment of poly(ethylene glycol) (PEG) and further with RGD-containing peptides. XPS analyses of modified surfaces after each reaction step reveal that the RGD-containing peptides have been covalently grafted onto PHBV films. The result of cell viability assay indicates that the RGD-modified PHBV films exhibit a distinctly improved cellular compatibility. Moreover, according to the results of serum adsorption tests by optical waveguide lightmode spectroscopy (OWLS) and fibrinogen adsorption tests by enzyme-linked immunosorbent assay (ELISA) on unmodified and modified PHBV surfaces, the introduced PEG chains can significantly decrease the nonspecific adsorption of proteins from serum and fibrinogen from plasma, thus decreasing the risk of thrombus formation and improving the blood compatibility of implanted materials.     

The use of graft copolymers to inhibit the adhesion of bacteria to solid surfaces

Twelve graft copolymers have been evaluated for their ability to prevent the adhesion of bacteria to substrata. The copolymers had polyethylene glycol (PEG) side-chains (‘teeth’) and a backbone that was either uncharged, acidic, basic or amphoteric. The copolymers were adsorbed onto glass, stainless steel and hydroxyapatite substrata, and 2-hpetri-dish adhesion experiments performed with bacteria isolated from marine (Pseudomonas sp. NCMB 2021), paper mill (S. marcescens NCIB 12211) and oral (S. mutans NCTC 10449) environments. The copolymers containing the most charged groups in the backbone had the most significant effect on bacterial adhesion levels, with anti-adhesive effects up to 99% achieved. An amphoteric copolymer (Compound 12) on glass, and acidic copolymer (Compound 11) on stainless steel and hydroxyapatite gave the most impressive anti-adhesive effects. These copolymers had non-specific bacterial anti-adhesive properties.It is proposed that the graft copolymers adsorbed onto hydrophilic surfaces via their charged backbone in such a way that the PEG side-chains were pointing out into the aqueous phase, and it was this orientation that was responsible for the observed anti-adhesive effect.     

Antibacterial activities of poly(amidoamine) dendrimers terminated with amino and poly(ethylene glycol) groups

Poly(amidoamine) (PAMAM) dendrimer derivatives have been investigated for their biological applications, especially for delivery of drugs, including antimicrobial drugs to eukaryotic cells, but their effects on bacterial cells are largely unexplored. Herein we report that amino-terminated PAMAM dendrimers are highly toxic to the common Gram-negative pathogen Pseudomonas aeruginosa. The concentration that kills 50% of the bacteria (EC50) was in the range of approximately 0.9-1.5 microg/mL for the generation 5, amino-terminated dendrimers with or without partial (43%) coating of poly(ethylene glycol) (PEG). These EC50 values were lower than that ( approximately 1.9-2.8 microg/mL) for LL-37, a potent antimicrobial peptide expressed in a variety of epithelia. On the contrary, the dendrimers were far less toxic (EC50 > 21 microg/mL) to the Gram-positive pathogen Staphylococcus aureus than LL-37 (EC50 = approximately 1.9 microg/mL). In agreement with the previous studies on other cell types, the dendrimers were not cytotoxic to human corneal epithelial cells at the concentrations that were toxic to P. aeruginosa. Our findings indicate that amino-terminated PAMAM dendrimers and their partially PEG-coated derivatives possess attractive antimicrobial properties, particularly against Gram-negative bacteria, thus expanding the potential biological application of the dendrimers.     

Adrenomedullin and mucosal defence: interaction between host and microorganism

Many surface epithelial cells express adrenomedullin (AM) and it is postulated that it may have an important protective role. This peptide has many properties in common with other cationic antimicrobial peptides including the human beta-defensins. Antimicrobial activity against members of the human skin, oral, respiratory tract and gastric microflora has been demonstrated. Both pathogenic and commensal strains of bacteria are sensitive; Gram-positive and Gram-negative bacteria being equally susceptible. No activity against the yeast Candida albicans was observed. Minimum inhibitory and minimum bacteriocidal concentrations range from 7.75 x 10(-4) to 12.5 and 0.003 to >25.0 microg ml(-1), respectively. On exposure of oral, skin and gastric epithelial cells to whole cells and culture supernatants from bacteria isolated from these sites an increase in AM peptide and gene expression has been observed. No upregulation was detected with C. albicans. In cultured cells and an animal infection model increased AM peptide and gene expression has been demonstrated using immunohistochemical and in situ hybridization techniques. These collective findings suggest that AM represents a new category of antimicrobial peptide, which contributes to the mucosal host defence system.     

Acute, same-day effects of antecedent exercise on counterregulatory responses to subsequent hypoglycemia in type 1 diabetes mellitus

Exercise-induced hypoglycemia can occur within hours after exercise in type 1 diabetes mellitus (T1DM) patients. This study tested the hypothesis that an acute exercise bout causes (within hours) blunted autonomic and metabolic responses to subsequent hypoglycemia in patients with T1DM. Twelve T1DM patients (3 W/9 M) were studied during a single-step, 2-h hyperinsulinemic (572 +/- 4 pmol/l) hypoglycemic (2.8 +/- 0.1 mmol/l) clamp 2 h after either a hyperinsulinemic euglycemic (AM EUG) or hypoglycemic clamp (AM HYPO) or after sitting in a chair with basal insulin infusion (AM CON) or 90 min of moderate-intensity exercise (50% Vo(2 max), AM EX). Both AM HYPO and AM EX significantly blunted epinephrine responses and muscle sympathetic nerve activity responses to subsequent hypoglycemia compared with both control groups. Endogenous glucose production was significantly lower and the exogenous glucose infusion rate needed to maintain the hypoglycemic level was significantly greater during subsequent hypoglycemia in AM EX vs. CON. Rate of glucose disposal (Rd) was significantly reduced following AM HYPO. In summary, within 2.5 h, both moderate-intensity AM EX and AM HYPO blunted key autonomic counterregulatory responses. Despite this, glucose Rd was reduced during afternoon hypoglycemia following morning hypoglycemia, indicating posthypoglycemic insulin resistance. After morning exercise, endogenous glucose production was blunted, but glucose Rd was maintained during afternoon hypoglycemia, thereby indicating reduced metabolic defenses against hypoglycemia. These data suggest that exercise-induced counterregulatory failure can occur very rapidly, increasing the risk for hypoglycemia in T1DM within hours.     

Antimicrobial activity of copper and silver nanofilms on nosocomial bacterial species

Contaminated surfaces are possible vehicles in infection transmission. It is known that both Copper (Cu) and Silver (Ag) efficiently inactivate microbes by direct contact. Aiming at using these metals for benefitting from their antimicrobial effect, but to avoid subsequent toxic effects, we evaluated the antimicrobial activity of nanometric thin Silver and Copper films covering less expensive materials. Using a modified version of the Japan Industrial Standard JIS Z 2801:2000, we demonstrated the antimicrobial activity of the surfaces covered with metal ions nanofilms on microorganisms possibly involved in nosocomial infections and on Bacillus anthracis, bacteria with possible implication in bioterrorist attacks. Copper covered surfaces proved to have better antimicrobial activity than Silver surfaces. Silver covered surfaces showed better activity on Gram negative bacteria than on Gram positive cocci. Going deeper with studies on antimicrobial effects using new methods with better direct and/or functional discriminatory capacity is needed in order to provide additional information on the mechanisms of Silver and Copper nanofilms antimicrobial activity.     

Effect of antimicrobial residues on early adhesion and biofilm formation by wild-type and benzalkonium chloride-adapted Pseudomonas aeruginosa

Antimicrobial residue deposition can change the physico-chemical properties of bacteria and surfaces and thus promote or impair bacterial adhesion. This study focuses on benzalkonium chloride (BC) deposition on polystyrene (PS) surfaces and the influence of this conditioning film on the physico-chemical properties of PS and on early adhesion and biofilm formation by Pseudomonas aeruginosa wild-type and its laboratory BC-adapted strain. The latter readily acquired the ability to grow in BC, and also exhibited physico-chemical surface changes. The existence of residues on PS surfaces altered their hydrophobicity and favoured adhesion as determined by the free energy and early adhesion characterization. Adapted bacteria revealed a higher ability to adhere to surfaces and to develop biofilms, especially on BC-conditioned surfaces, which thereby could enhance resistance to sanitation attempts. These findings highlight the importance of investigations concerning the antimicrobial deposition effect after cleaning procedures, which may encourage bacterial adhesion, especially of bacteria that have been previously exposed to chemical stresses.