Carrier tests to assess microbicidal activities of chemical disinfectants for use on medical devices and environmental surfaces

For well over a decade, many deficiencies have been identified in current AOAC methods used to assess the microbicidal activities of chemical disinfectants on medical devices and environmental surfaces. This report discusses the development of quantitative carrier tests (QCT) designed to address these concerns. Decontamination of surfaces with dried inocula is invariably more difficult than when microorganisms are in suspension. For medical device as well as environmental decontamination, microbicides are used on contaminated surfaces, thus making it necessary to evaluate their microbicidal action on representative carrier materials contaminated with a dried challenge microorganism(s). Our approach is a 2-tiered QCT. The first tier (QCT-1) uses relatively ideal conditions to assess performance of the microbicide for screening purposes; the test uses smooth glass surfaces and quantities of disinfectant in excess of those likely to be experienced in the field. The second tier of testing (QCT-2) is more stringent because it uses (1) disks of brushed stainless steel as carriers, (2) only 50 microL of the test formulation on each carrier as compared to 1 mL in QCT-1, and (3) an added soil load to simulate the presence of residual body fluids or accumulated surface dirt. This review also discusses the factors that affect disinfection of medical devices and environmental surfaces in the context of the methodology used to evaluate the potency of microbicides. Specific recommendations for discussion are included, and performance criteria are suggested based on a risk-reduction approach for different classes of disinfectants. The focus is on improving the relevance of the test methodology to actual field use of disinfectants for devices and facilities in health care, and potentially in other settings. It is hoped that this review and its recommendations will initiate needed discussion and resolution of the many issues identified.     

Microbiological methods for testing disinfectant efficiency on Pseudomonas biofilm

Biofilms of the Gram-negative bacteria Pseudomonas aeruginosa and Pseudomonas fragi were grown on stainless steel surfaces (AISI 304, 2B) for 4 days in slime broth. These biofilms were treated with four commercial disinfectants. The disinfectants were alcohol-based, tenside-based, peroxide-based and chlorine-based products, covering most disinfectant types used in the food industry. The effects of the disinfectants on the bacterial cells were first investigated in suspension using the permeabilisation test, which is based on fluorescence assessment of hydrophobic 1-N-phenyl-naphtylamine (NPN). The surfaces covered with disinfectant-treated biofilms were investigated using conventional cultivation, impedimetry and epifluorescence microscopy in combination with image analysis of preparations stained with the DNA-stain acridine orange and with the metabolic indicator system CTC-DAPI. The results showed that the tenside-based and peroxide-based disinfectants permeabilised the cells in suspension. The overall biofilm results showed that of the agents tested, the peroxide-based and chlorine-based disinfectants acted most effectively on cells in biofilms.     

Biocide Use in the Antimicrobial Era: A Review

Biocides are widely used in healthcare and industry to control infections and microbial contamination. Ineffectual disinfection of surfaces and inappropriate use of biocides can result in the survival of microorganisms such as bacteria and viruses on inanimate surfaces, often contributing to the transmission of infectious agents. Biocidal disinfectants employ varying modes of action to kill microorganisms, ranging from oxidization to solubilizing lipids. This review considers the main biocides used within healthcare and industry environments and highlights their modes of action, efficacy and relevance to disinfection of pathogenic bacteria. This information is vital for rational use and development of biocides in an era where microorganisms are becoming resistant to chemical antimicrobial agents.     

UV Inactivation of Common Pathogens and Surrogates Under 222 nm Irradiation from KrCl* Excimer Lamps

Germicidal ultraviolet (UV) devices have been widely used for pathogen disinfection in water, air, and on food and surfaces. Emerging UV technologies, like the krypton chloride (KrCl*) excimer emitting at 222 nm, are rapidly gaining popularity due to their minimal adverse effects on skin and eyes compared with conventional UV lamps emitting at 254 nm, opening opportunities for UV disinfection in occupied public spaces. In this study, inactivation of seven bacteria and five viruses, including waterborne, foodborne and respiratory pathogens, was determined in a thin-film aqueous solution using a filtered KrCl* excimer emitting primarily at 222 nm. Our results show that the KrCl* excimer can effectively inactivate all tested bacteria and viruses, with most microorganisms achieving more than 4-log (99.99%) reduction with a UV dose of 10 mJ cm⁻². Compared with conventional UV lamps, the KrCl* excimer lamp exhibited better disinfection performance for viruses but was slightly less effective for bacteria. The relationships between UV sensitivities at 222 and 254 nm for bacteria and viruses were evaluated using regression analysis, resulting in factors that could be used to estimate the KrCl* excimer disinfection performance from well-documented UV kinetics using conventional 254 nm UV lamps. This study provides fundamental information for pathogen disinfection when employing KrCl* excimers.     

Photochemical inactivation of Pseudomonas aeruginosa

Adaptability to a broad range of environments together with relatively high resistance to antibiotics and to disinfectants makes Pseudomonas aeruginosa a concern in hospitals and in public health. We investigated whether UVA-mediated photochemical inactivation of P. aeruginosa could be accomplished with high efficiency while at the same time preserving the sensitivity of subsequent diagnostic tests. We characterized dose responses and bactericidal kinetic rates of 5-iodonaphthyl 1-azide (INA) and of amotosalen (AMO) as these substances exposed to UVA are known to inactivate germs with minimal impact to blood products or to viral antigens. Neither UVA without photochemicals nor INA or AMO in the dark inactivated bacteria. We found that AMO was ca 1000-fold more effective in inactivating P. aeruginosa cells than INA under similar conditions. Photoinactivation with either INA or AMO at conditions that abolished bacterial infectivity did not impair polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) testing. For comparison, similar titers of Bacillus atrophaeus spores (a surrogate for B. anthracis) remained unaffected at conditions that reduced the survival of P. aeruginosa below detection levels. The results presented in this study should assist in improved methods to inactivate P. aeruginosa in environmental, clinical and forensic samples without impairing subsequent nucleic acid- or immune-based analysis.     

Synthesis of silver nanoparticles in an aqueous suspension of graphene oxide sheets and its antimicrobial activity

A solution-based approach to the synthesis of silver (Ag) nanoparticles by chemical reduction of AgNO(3) in a graphene oxide (GrO) suspension is demonstrated. X-ray diffraction and transmission electron microscopy indicate that the Ag nanoparticles, of size range 5-25nm, were decorated on the GrO sheets. The size and shape of the Ag nanoparticles are dependent on the concentration of the AgNO(3) solution. Antimicrobial activity of such hybrids materials is investigated against the Gram negative bacteria Escherichia coli and Pseudomonous aeruginosa. The bacterial growth kinetics was monitored in nutrient broth supplemented with the Ag nanoparticle-GrO suspension at different conditions. It was observed that P. aeruginosa is comparatively more sensitive to the Ag nanoparticle-GrO suspension.     

A UVC device for intra-luminal disinfection of catheters: in vitro tests on soft polymer tubes contaminated with Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli and Candida albicans

Bacterial colonization of central venous catheters (CVCs) causes severe complications in patients. As a result, developing methods to remove and prevent bacterial and fungal colonization of CVCs is imperative. Recently, we have demonstrated that disinfection by radiation of polymer tubes with UVC light is possible. In this paper we present dose-response results using a newly developed UVC disinfection device, which can be connected to a Luer catheter hub. The device was tested on soft polymer tubes contaminated with a pallet of microorganisms, including Candida albicans, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa (ca 10(3) CFU mL(-1)). The tubes were equipped with a modified catheter hub and interfaced to the disinfection device via a middle piece separating the disinfection device from the hub. The contamination lasted for 3 h prior to treatment to simulate an aseptic breach. Our results show UVC killing in a dose and time dependent manner, with no viable counts after 2 min of radiation for bacteria. Killing of C. albicans was obtained at >20 min in an UVC absorbing suspension. We believe our results to be transferable directly to the clinic, and we are currently working on a setup for clinical trial.     

Bacterial capture efficiency and antimicrobial activity of phage-functionalized model surfaces

The rise of antibiotic-resistant bacteria has directed substantial attention toward the use of bacteriophages as a means to control bacterial populations. It has been proposed that bacteriophages can be applied as a coating on surfaces in healthcare settings or on indwelling medical devices to create an antimicrobial surface. In this study, antimicrobial model surfaces functionalized with five different types of bacteriophage were prepared and characterized with X-ray photoelectron spectroscopy and atomic force microscopy. The bacterial capture efficiency of these functionalized surfaces was studied for two common bacteria, Escherichia coli and Salmonella typhimurium. Binding of the phages to a solid surface affected their biofunctionality as expressed by the capture efficiency and rate of host membrane disruption. Moreover, the size and shape of the bacteriophage and positioning of its specific binding proteins significantly affected its bacterial capture capability in the immobilized state. Symmetric bacteriophages were found to be a better choice for antibacterial surfaces compared to more asymmetric tailed bacteriophages. Immobilized phages were found to disrupt the membranes of attached bacteria and are thus proposed as a candidate for antimicrobial surfaces.     

In vitro production of Clostridium difficile spores for use in the efficacy evaluation of disinfectants: a precollaborative investigation

Clostridium difficile is a strict anaerobic spore-forming bacterium, and an increasingly common nosocomial pathogen. The U.S. Environmental Protection Agency (EPA) is responsible for the registration of disinfectants, including products designed to treat environmental surfaces contaminated with spores of C. difficile. Product efficacy data are required for registration; however, there is a lack of methodology for generating high-quality spore suspensions for evaluating product performance. As such, a study was carried out to select a suitable C. difficile strain and to develop a stand-alone method to prepare a spore suspension that meets specific criteria necessary for quantitative testing of disinfectants. The criteria are: (1) a spore titer of > 8 log10/mL, (2) > or = 90% spores to vegetative cells, and (3) resistance of spores (determined by viability) to 2.5 M hydrochloric acid (HCl). Several strains of C. difficile (toxigenic and nontoxigenic) were grown on various media (solid and liquid) for varying lengths of time to determine the best combination of incubation conditions and media to optimize spore production and quality. Once the spore production procedure was optimized, a toxigenic strain of C. difficile [American Type Culture Collection (ATCC) 43598] was selected for use in trials to verify repeatability from one production run to the next. The spore suspension was initiated by spreading vegetative cells of C. difficile (ATCC 43598) on CDC anaerobic 5% sheep blood agar plates and incubating for 7-10 days at 36 +/- 1 degrees C under anaerobic conditions. Spores were harvested when > or = 90% of the cells converted to spores as determined by observation using phase-contrast microscopy. The spores were washed three times with saline-Tween-80, resuspended in cold deionized water, heated to 70 degrees C for 10 min, evaluated microscopically for quality, and enumerated on cycloserine-cefoxitin-fructose agar containing horse blood and taurocholate. The spore suspension was used to inoculate brushed stainless steel carriers (1 cm in diameter) with and without a soil load in accordance with the Standard Quantitative Carrier Disk Test Method (ASTM E-2197-02) to determine carrier load. Once it was determined that > 6 log10 spores/carrier could be recovered, spores were evaluated for resistance to HCI. The sporulation method presented in this report is simple and repeatable and results in spore suspension of high titer (> 8 log10/mL) and quality (> or = 90% spores to vegetative cells) that met acid resistance criteria (spores were resistant to 2.5 M HCI for 10 min). In addition, recovery from brushed stainless steel carriers with and without soil load was > 6 log10 spores/carrier. A 6 log10 performance standard was set forth in the EPA's interim guidance for generating data to support a label claim for effectiveness against C. difficile spores on hard, nonporous surfaces. This precollaborative investigation successfully demonstrated the use of a methodology for in vitro production of C. difficile spores (ATCC 43598) necessary for conducting efficacy tests. A proposal will be submitted to the AOAC INTERNATIONAL Methods Committee on Antimicrobial Efficacy Testing for a collaborative study; see Appendix.     

An investigation of the bactericidal and fungicidal effects of certain disinfectants by use of a capacity test

The bactericidal and fungicidal effects of five disinfectants and one combination of two disinfectants were tested using a modified Kelsey-Sykes method in which living microorganisms suspended in a sterilized yeast suspension («dirtyå conditions) and in sterile distilled water («cleanå conditions) were added to the disinfectants in three stages. Six bacteria and two fungal organisms were employed as test microbes.Results showed that formaldehyde was virtually inactive at the dilution tested (1/50), whereas phenol and the combination propylene-phenoxetol +benzalkonium chloride were moderately effective, the latter compound being better. Glutaraldehyde was manifestly the most effective of the disinfectants tested, followed by tricresol. At a 1/50 dilution, chloramine proved to have a surprisingly strong fungicidal effect on Candida albicans and Aspergillus fumigatus under «dirtyå conditions, whereas the same fungal organisms proved rather resistant to chloramine under «cleanå conditions. The same was demonstrated–though less markedly—when higher dilutions o chrloramine were used. The search for an explanation is still in progress. At relatively high dilutions, chloramine also proved effective against most of the test bacteria, especially under «cleanå conditions. It is recommended that the yeast suspension of chloramine against fungal strains under «dirtyå conditions.     

Bacteria‐Triggered Release of Antimicrobial Agents

Medical devices employed in healthcare practice are often susceptible to microbial contamination. Pathogenic bacteria may attach themselves to device surfaces of catheters or implants by formation of chemically complex biofilms, which may be the direct cause of device failure. Extracellular bacterial lipases are particularly abundant at sites of infection. Herein it is shown how active or proactive compounds attached to polymeric surfaces using lipase‐sensitive linkages, such as fatty acid esters or anhydrides, may be released in response to infection. Proof‐of‐concept of the responsive material is demonstrated by the bacteria‐triggered release of antibiotics to control bacterial populations and signaling molecules to modulate quorum sensing. The self‐regulating system provides the basis for the development of device‐relevant polymeric materials, which only release antibiotics in dependency of the titer of bacteria surrounding the medical device.     

Nano/microscale order affects the early stages of biofilm formation on metal surfaces

The adhesion of Pseudomonas fluorescens was studied on nano/microengineered surfaces. Results show that these bacteria formed well-defined aggregates on randomly oriented nanosized granular gold substrates. These aggregates consist of aligned ensembles of bacteria, with some of them strongly elongated. This kind of biological structure was not found on ordered engineered surfaces because bacterial alignment and cell-to-cell sticking were hindered. Importantly, differences in cell morphology, length, orientation, and flagellation were observed between bacteria attached on the ordered nano/microstructures and the randomly ordered surfaces. The implications of the results are related to the design of engineered surfaces to enhance (nanostructured filters) or inhibit (medical implants and industrial biofouling) bacterial colonization on the surfaces and to the biocontrol of soil ecosystems.     

Monitoring metal ion binding in single-layer Pseudomonas aeruginosa biofilms using ATR-IR spectroscopy

The binding of metal ions to Pseudomonas aeruginosa PAO1 cells attached to a ZnSe surface has been observed in this research through cation exchange experiments using ATR-IR spectroscopy. A biofilm consisting of a single layer of Pseudomonas aeruginosa PAO1 cells was formed on a ZnSe prism by flowing a bacterial suspension in a 0.03 mol L(-)(1) NaNO(3) solution at pH 5.0 across its surface. Exposure of the biofilm to chromium(III) nitrate solution resulted in increases in all band absorbances. This absorbance increase has been attributed to the binding of chromium(III) to the bacterial exopolymers associated with the prism surface. The chromium(III) binding causes the exopolymers to contract and move the bacterial cell closer to the ZnSe surface. Further study of chromium(III) ion exchange using a mutant P. aeruginosa with a truncated lipopolysaccharide (LPS) chain resulted in much smaller absorbance changes. This observation supports the view that the extension of bacterial exopolymers and hence the distance of the bacterial cell from the surface is strongly influenced by environmental factors such as the presence of metal cations. Following chromium(III) cation exchange, the bacterial band absorbances remained constant even when the bacteria were washed with a 0.03 mol L(-)(1) NaNO(3) solution, indicating that the chromium(III) was irreversibly bound. Ion exchange with nickel(II) and cobalt(II) nitrate solutions within identical biofilms showed that these cations caused relatively small increases in absorbances that were reversible, indicating that nickel(II) and cobalt(II) are less strongly bound than chromium(III) within P. aeruginosa biofilms. The absence of discernible IR spectral changes with metal binding appears to indicate a predominantly electrostatic mechanism for binding of Cr(III), Ni(II), and Co(II) ions by bacteria in the early stages of biofilm formation.     

The effect of surface wettability on induction and growth of neurites from the PC-12 cell on a polymer surface

Surface properties of polymeric devices that are used to regenerate nervous damage are a point to be considered for axon regeneration in nerve system. In our previous studies, we prepared a wettability gradient on polyethylene (PE) surfaces using a corona discharge treatment from a knife-type electrode whose power increases gradually along the sample length. The PE surfaces were oxidized gradually with increasing power. The effect of surface wettability on the different types of cells has an important role for cell adhesion and proliferation. The purpose of this study is to investigate neurite formation on polymer surfaces with different wettability. Induction and growth of neurites from the rat pheochromocytoma (PC-12) cells attached on the polymer surfaces with different hydrophilicity were investigated using the wettability gradient PE surfaces prepared by a corona discharge treatment. Neurites were investigated for number and length of neurites in terms of surface wettability. It was observed that neurite formation of PC-12 cells was increased more onto the positions with moderate hydrophilicity of the wettability gradient surface than onto the more hydrophobic or hydrophilic positions. From those results, it could be assumed that initial adhesion of PC-12 cells was caused by more calf serum (CS) protein than nerve growth factor (NGF), whereas the neurite formation of PC-12 cells was caused by more NGF than CS protein. It follows from what has been said thus far that PC-12 cells are a differentiated neuronal phenotype with a long neurite at around the position 2.5 cm (water contact angle of about 55 deg). In conclusion, surface wettability plays an important role for neurite formation on the polymer surfaces for axon regeneration.     

Theoretical and experimental aspects of microbicidal activities of hard surface disinfectants: are their label claims based on testing under field conditions?

High-touch environmental surfaces are important in the spread of many nosocomial pathogens. Although such surfaces are routinely disinfected, the testing and label claims of many common disinfectants do not reflect the realities of field use. A study was conducted to determine the influence of several crucial factors on the action of disinfectants in general, and to assess the killing efficiency of selected chemistries against Staphylococcus aureus and Pseudomonas aeruginosa, related to their drying times (i.e., after one application) and label-specified contact times using a quantitative carrier test. The products were also tested for their ability to wet a hydrophobic (epoxy resin) surface. The hard-surface disinfectants (in-use concentration in ppm) tested were: (a) chlorine bleach (500); (b) quaternary ammonium compounds (quat; 600) alone; (c) quat (3000) with 17% isopropanol (v/v); (d) quat (3000) with 60% ethanol (v/v); (e) phenolic (800) alone; (f) quat (2000), phenolic (3000) with 70% ethanol (v/v); and (g) accelerated hydrogen peroxide (AHP; 5000 of H2O2). The arbitrarily set criterion of bactericidal activity was > or = 6 log10 reduction in the viability of both species tested. All surfaces tested with all products dried in < 5 min, with alcohol-based surfaces drying significantly faster. Even though the alcohol-free quat and phenolic claim a contact time of 10 min, they dried in < 4 min after a single application and failed to meet the performance criterion. Bleach (500 ppm) dried in about 3 min and was effective. AHP also dried in about 3 min and met its label claim even at 1 min of contact. Quat (3000) with 17% isopropanol dried at 1 min and was effective. Quat (3000) with 60% ethanol and quat (2000), phenolic (3000) with 70% ethanol dried in < 1 min, and were ineffective. AHP, alcohol-containing quats, and quat-phenolic-alcohol gave acceptable wettability, while quat and phenolic alone, as well as bleach, covered the treated surface unevenly. The findings show that label claims, especially those for contact times, fail to reflect the way many hard-surface disinfectants are used in the field.     

Effect of monovalent and divalent cations on the photoinactivation of bacteria with meso-substituted cationic porphyrins

It is well established that for successful photoinactivation (PI) of gram-negative bacteria a cationic photosensitizer is required. This requirement suggests a charge-dependent interaction between the photosensitizer and the gram-negative bacterium, which may be influenced by the presence of ions in the suspending medium. The aim of the present study was to investigate the effect of cations Na+ and Ca2+ on the efficacy of the PI of the gram-negative Pseudomonas aeruginosa and the gram-positive Staphylococcus aureus. The bacteria were suspended in buffer containing either meso-tetra(N-methyl-4-pyridyl)-porphyrin or meso-mono-phenyl-tri(N-methyl-4-pyridyl)-porphyrin as photosensitizer and various concentrations of Na+ or Ca2+. The cell suspensions were exposed to a broadband light dose of 9 J/cm2. In buffer without added cations, P. aeruginosa and S. aureus were equally sensitive to PI. Addition of cations strongly decreased the sensitivity of both bacteria to PI, with the PI of P. aeruginosa being much more decreased than that of S. aureus, and Ca2+ being more effective than Na+. The decreased sensitivity was accompanied by a reduced binding of the photosensitizers to the bacteria.     

Using Chemoattractants to Lure Bacteria to Contact‐Killing Surfaces

Antimicrobial surfaces with covalently attached biocidal functionalities only kill microbes that come into direct contact with the surfaces (contact‐killing surfaces). Herein, the activity of contact‐killing surfaces is shown to be enhanced by using gradients in the concentration of soluble chemoattractants (CAs) to attract bacteria to the surfaces. Two natural and nonbiocidal CAs (aspartate and glucose) were used to attract bacteria to model surfaces decorated with quaternary ammonium groups (known to kill bacteria that come into contact with them). These results demonstrate the killing of Escherichia coli and Salmonella typhimurium, two common pathogens, at levels 10‐ to 20‐times greater than that of the native surfaces alone. This approach is general and provides new strategies for the design of active or dynamic contact‐killing surfaces with enhanced antimicrobial activities.     

Dynamics of Pseudomonas aeruginosa association with anionic hydrogel surfaces in the presence of aqueous divalent-cation salts

Binding of bacteria to solid surfaces is complex with many aspects incompletely understood. We investigate Pseudomonas aeruginosa uptake kinetics onto hydrogel surfaces representative of soft-contact lenses made of nonionic poly(2-hydroxyethylmethacrylate) (p-HEMA), anionic poly(methacrylic acid) (p-MAA), and anionic poly(acrylic acid) (p-AA). Using a parallel-plate flow cell under phase-contrast microscopy, we document a kinetic "burst" at the anionic hydrogel surface: dilute aqueous P. aeruginosa first rapidly accumulates and then rapidly depletes. Upon continuing flow, divalent cations in the suspending solution sorb into the hydrogel network causing the previously surface-accumulated bacteria to desorb. The number of bacteria eventually bound to the surface is low compared to the nonionic p-HEMA hydrogel. We propose that the kinetic burst is due to reversible divalent-cation bridging between the anionic bacteria and the negatively charged hydrogel surface. The number of surface bridging sites diminishes as divalent cations impregnate into and collapse the gel. P. aeruginosa association with the surface then falls. Low eventual binding of P. aeruginosa to the anionic hydrogel is ascribed to increased surface hydrophilicity compared to the counterpart nonionic p-HEMA hydrogel.     

Spectroscopic study of decontaminated corroded carbon steel surfaces

Removal of uranium from contaminated carbon steel surfaces by chelation with hydroxycarboxylic acid has been tested as a cleaning process for decommissioning and decontaminating contaminated surfaces. Comparison of contaminated surfaces prior to decontamination with subsequently cleaned surfaces was done in order to study the effectiveness of this cleaning technique. This was accomplished using various spectroscopic techniques, including x‐ray photoelectron spectroscopy, synchrotron infrared microspectroscopy, Rutherford backscattering spectroscopy and scanning electron microscopy/energy‐dispersive spectroscopy. Mild carbon steel (1010) coupons were exposed to uranyl nitrate solution, which led to the formation of a lightly corroded surface. Some contaminated samples underwent further cyclic humidity treatment, during which additional corrosion took place. In this study, it was found that a citric acid–hydrogen peroxide–citric acid cleaning method successfully removed uranium in lightly corroded areas. However, the method but incompletely decontaminated some heavily corroded areas where more highly crystallized corrosion products are found or where complex surface structure can occlude contaminants. Use of complementary analytical techniques is essential to provide an accurate model of surface chemistry before and after decontamination. Copyright © 2004 John Wiley & Sons, Ltd.     

TiO2 films by sol-gel spin-coating deposition with microbial antiadhesion properties

Intensive use of antibiotics induced adaptations in bacteria, which developed antibiotic resistance. This is becoming a serious health problem, particularly in the hospital, food industry, or public transport. It is also important to produce surfaces that not only are bactericidal but also prevent adhesion and the consequent biofilm formation, which can make the bacteria resistant to conventional disinfection methods. In this work, a simple and inexpensive method to obtain surfaces TiO₂ film coated has been realized to prevent attachment and bacterial proliferation on surfaces. The synthesis and deposition procedure has been finalized to the realization of a uniform coating, whose physical, morphological, and structural features are suitable to inhibit the proliferation of the bacteria and in particular the adhesion of the biofilm. The suitability of the obtained coating has been attested by RBS, X-ray diffraction (XRD), SEM, UV-vis, and Raman techniques. The obtained coatings were homogeneous anatase titania films with an excellent adherence to the substrate and a transmittivity higher than 80% in the visible region. The results show that the TiO₂ films considerably reduce microbial contamination on the surface (~98% reduction) feature that makes this coating suitable for antibacterial applications.