Long-lasting Antibacterial Properties Research Articles

Antibacterial activity of a modified unfilled resin containing a novel polymerizable quaternary ammonium salt MAE-HB.

Resins with strong and long-lasting antibacterial properties are critical for the prevention of secondary dental caries. In this study, we evaluated the antibacterial effect and the underlying mechanism of action of an unfilled resin incorporating 2-methacryloxylethyl hexadecyl methyl ammonium bromide (MAE-HB) against Streptococcus mutans UA159 (S. mutans UA159). MAE-HB was added into unfilled resin at 10 mass%, and unfilled resin without MAE-HB served as the control. Bacterial growth was inhibited on 10%-MAE-HB unfilled resin compared with the control at 1 d, 7 d, 30 d, or 180 d (P < 0.05). The growth inhibitory effect was independent of the incubation time (P > 0.05). No significant differences in the antibacterial activities of eluents from control versus 10%-MAE-HB unfilled resins were observed at any time point (P > 0.05). The number of bacteria attached to 10%-MAE-HB unfilled resin was considerably lower than that to control. Fe-SEM and CLSM showed that 10%-MAE-HB unfilled resin disturbed the integrity of bacterial cells. Expression of the bacterial glucosyltransferases, gtfB and gtfC, was lower on 10%-MAE-HB unfilled resin compared to that on control (P < 0.05). These data indicate that incorporation of MAE-HB confers unfilled resin with strong and long-lasting antibacterial effects against S. mutans.

Direct incorporation of silver nanoparticles onto thin-film composite membranes via arc plasma deposition for enhanced antibacterial and permeation performance

We report on a new technique that incorporates silver nanoparticles (AgNPs) onto polyamide (PA) thin film composite (TFC) reverse osmosis membranes via arc plasma deposition (APD) to impart antibacterial properties and simultaneously improve membrane performance. APD allows the direct deposition of AgNPs under vacuum dry condition, overcoming the drawbacks of the conventional wet-chemical methods. AgNPs (~7.6nm in diameter) were uniformly distributed without aggregation throughout the PA selective layer with some partially implanted into the PA matrix. Ag loading could be tuned by simply adjusting the number of APD purse shots. The deposited AgNPs exhibited good leaching stability, presumably due to the strong Ag-PA chemical interaction and partially buried AgNP morphology. The resulting Ag-incorporated TFC (Ag-TFC) membrane showed the strong and long-lasting antibacterial properties for both gram-negative and -positive bacteria. Simultaneously, the Ag-TFC membrane exhibited an enhancement in water flux of approximately 40% without deterioration in NaCl rejection. These performance changes were tentatively attributed to the partial destruction of the PA layer under the high energetic APD condition along with the increased membrane hydrophilicity. Hence, the APD process provides a simple and effective route to modify membranes with functional NPs.

Lethal bacterial trap: Cationic surface for endodontic sealing.

Insoluble antibacterial cationic nanoparticles have been previously shown to have potent and long-lasting antibacterial properties. Our tested hypothesis was that root canal pathogens will be attracted to and eliminated when exposed to epoxy resin-based surfaces incorporating cationic nanoparticles. In our research, an epoxy resin-based surface incorporating quaternary ammonium polyethyleneimine (QPEI) nanoparticles was evaluated. Surface characterization was performed using atomic force microscopy and X-ray photoelectron spectra. The surface anti-Enterococcus faecalis effect was evaluated in an anti-gravitational model. Cell membrane potential, viability, biofilm thickness, and biomass were tested using flow cytometry and confocal laser scanning microscopy. Additionally, the antibiofilm activity of the bacterial supernatant was assessed. The surface characterization showed QPEI nanoparticle embedment on the modified sealer. The epoxy resin-based surface incorporating the QPEI nanoparticles actively attracted bacteria, causing membrane destabilization, and bacterial death. The supernatant of bacteria pre-exposed to QPEI showed an antibacterial effect. In conclusion, the tested epoxy resin-based surface incorporating QPEI nanoparticles traps and kills bacteria. The nanoparticles attracted bacteria, reducing their viability, and promoting cell death.

An invitro evaluation of antibacterial properties of self etching dental adhesive systems.

The microbial flora of the oral cavity is extremely diverse. Residual bacteria in the oral cavity may remain at the tooth restoration interface and increase the risk of developing recurrent caries. The aim of this study is to evaluate the immediate and long term antibacterial effect of polymerised self etching adhesive systems. Streptococcus mutans were used as a test organism. The self etching dental adhesives that were used are Adper Easy One, G-Bond, Clearfil S3 bond and Xeno V. Agar diffusion test (ADT) was performed on agar plates, in which four holes that were 4mm in diameter were punched. Then 200 μL of freshly grown S.mutans spread evenly. The four holes were immediately filled with the four tested materials and light polymerised them using a light curing unit. The agar plates were incubated for 72h at 37°C. For the direct contact test (DCT), the bonding agents were placed on the side walls of microtiter plate wells and light polymerized according to the manufacturer's instructions. A 10μL bacterial suspension was placed on the tested material samples. Bacteria were allowed to directly contact the polymerized dental adhesives for 1h at 37(o)C. Fresh Brain heart infusion broth was then added. The bacterial growth was then spectrophotometrically measured in the wells every 30 min for 16h for 1,2, 7 and 14 days. In the ADT, inhibitory halos were found around all the bonding agents, with greater inhibition halo seen around Xeno V after incubating for 72 h at 37°C. The readings obtained through DCT were subjected to ANOVA and Tukey's multiple comparisons tests, which showed no bacterial growth on fresh samples and after aging for one day in PBS with self etching adhesives. RESULTS of DCT after aging for 2 days, 7 days and 14 days showed bacterial growth in all the bonding agents used with no significant difference from the control group.(p<0.001) CONCLUSION: All the dental adhesives showed antibacterial properties immediately and one day after polymerization but none of the self-etching adhesives had long-lasting antibacterial properties.

Green and facile fabrication of silver nanoparticles loaded activated carbon fibers with long-lasting antibacterial activity

Silver nanoparticles (AgNPs) with diameter of about 50 nm were successfully loaded on the surface of activated carbon fibers (ACFs) via a facile and green hydrothermal route. The XRD and XPS results demonstrated that the silver loaded on ACFs surfaces was in metallic form of Ag0. Effects of preparation conditions of pH and reaction time were investigated. pH of the reaction solution was essential for the formation of AgNPs on the ACFs surface. The possible formation mechanism was proposed on the basis of the XPS results. The prepared material was tested for its antibacterial property against typical Gram-positive and Gram-negative bacteria of S. aureus and E. coli, both of which showed good bactericidal efficiency. The stability of the loading was justified by washing the material with water. The long-lasting antibacterial property of the material is of significant practical importance for water purification. Electricity introduced into the system can drastically improve the bactericidal efficiency to 100% in 10 min.

Role of the anions in the hydrothermally formed silver nanowires and their antibacterial property

Uniform silver nanowires were synthesized via a green and simple hydrothermal method through fine tailoring the anions in the precursors. The results indicate that the anions added to the reaction precursors played a key role in determining the morphology and composition of the final products. A new possible mechanism is proposed that in the hydrothermal process AgxAy act as another oxidant except for Ag+ ions. The obtained silver nanowires showed excellent and long-lasting antibacterial property.

A new concept in polymeric thin-film composite nanofiltration membranes with antibacterial properties

A new, thin film, biofouling resistant, nanofiltration (NF) membrane was fabricated with two key characteristics, viz. a low rate of silver (Ag) release and long-lasting antibacterial properties. In the new approach, nanoparticles were embedded completely in a polymeric thin-film layer. A comparison was made between the new thin-film composite (TFC), NF membrane and thin-film nanocomposite (TFN), and antibacterial NF membranes. Both types of NF membrane were fabricated by interfacial polymerization on a polysulphone sublayer using m-phenylenediamine and trimesoyl chloride as an amine monomer and an acid chloride monomer, respectively. Energy dispersive X-ray (EDX) microanalysis demonstrated the presence of Ag nanoparticles. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to study the cross-sectional and surface morphological properties of the NF membranes. Permeability and salt rejection were tested using a dead-end filtration cell. Ag leaching from the membranes was measured using inductively coupled mass spectrometry (ICP–MS). Morphological studies showed that the TFC NF membranes had better thin-film formation (a more compact structure and a smoother surface) than TFN NF membranes. Performance experiments on TFC NF membranes revealed that permeability was good, without sacrificing salt rejection. The antibacterial properties of the fabricated membranes were tested using the disk diffusion method and viable plate counts. The antibiofouling properties of the membranes were examined by measuring the quantity of bacterial cells released from the biofilm formed (as a function of the amount of biofilm present). A more sensitive surface was observed compared to that of a typical antibacterial NF membrane. The Ag leaching rates were low, which will likely result in long-lasting antibacterial and biofouling resistant properties.

Effect of water-ageing on dentine bond strength and anti-biofilm activity of bonding agent containing new monomer dimethylaminododecyl methacrylate

ObjectivesThe objectives of this study were to develop bonding agent containing a new antibacterial monomer dimethylaminododecyl methacrylate (DMADDM) as well as nanoparticles of silver (NAg) and nanoparticles of amorphous calcium phosphate (NACP), and to investigate the effects of water-ageing for 6 months on dentine bond strength and anti-biofilm properties for the first time. MethodsFour bonding agents were tested: Scotchbond Multi-Purpose (SBMP) Primer and Adhesive control; SBMP+5% DMADDM; SBMP+5% DMADDM+0.1% NAg; and SBMP+5% DMADDM+0.1% NAg with 20% NACP in adhesive. Specimens were water-aged for 1d and 6 months at 37°C. Then the dentine shear bond strengths were measured. A dental plaque microcosm biofilm model was used to inoculate bacteria on water-aged specimens and to measure metabolic activity, colony-forming units (CFUs), and lactic acid production. ResultsDentine bond strength showed a 35% loss in 6 months of water-ageing for SBMP control (mean±sd; n=10); in contrast, the new antibacterial bonding agents showed no strength loss. The DMADDM–NAg–NACP containing bonding agent imparted a strong antibacterial effect by greatly reducing biofilm viability, metabolic activity and acid production. The biofilm CFU was reduced by more than two orders of magnitude, compared to SBMP control. Furthermore, the DMADDM–NAg–NACP bonding agent exhibited a long-term antibacterial performance, with no significant difference between 1d and 6 months (p>0.1). ConclusionsIncorporating DMADDM–NAg–NACP in bonding agent yielded potent and long-lasting antibacterial properties, and much stronger bond strength after 6 months of water-ageing than a commercial control. The new antibacterial bonding agent is promising to inhibit biofilms and caries at the margins. The method of DMADDM–NAg–NACP incorporation may have a wide applicability to other adhesives, cements and composites.

In-vitro Comparison of the Antimicrobial Properties of Glass Ionomer Cements with Zinc Phosphate Cements.

White spot lesions are observed in nearly 50% of patients undergoing orthodontic treatment. Long-lasting antibacterial properties of orthodontic cements can reduce this phenomenon. The aim of this research was to compare antimicrobial activity of three commercial glass ionomer cements with three commercial zinc phosphate cements, over time, against streptococcus mutans and candida albicans. Direct contact test (DCT) was used to evaluate the antibacterial and antifungal activity of products after 48 h and 7 days of incubation. The results demonstrated that all the cements presented antibacterial activity but the antibacterial activity of glass ionomer cements was more than that of zinc phosphate cements. Counts of C. albicans after 48 h were lower and statistically different in the GIC group in relation to the control groups. But no differences were observed between GIC and control groups at 7 days. Based on the results of this study, the antimicrobial and mainly antifungal effects of all the cements were so short.

Antibacterial nanofiber materials activated by light

Electrospun polymeric nanofiber materials doped with 5,10,15,20-tetraphenylporphyrin (TPP) photosensitizer were prepared from four different polymers and were characterized with microscopic methods, steady-state, and time-resolved fluorescence and absorption spectroscopy. The polymers used included polyurethane Larithane™ (PUR), polystyrene (PS), polycaprolactone (PCL), and polyamide 6 (PA6). The antibacterial activity of all nanofiber materials against E. coli was activated by visible light and it was dependent on oxygen permeability/diffusion coefficients and the diameter of the polymeric nanofibers. This activity is based on oxidation ability of singlet oxygen O₂(¹Δ(g)) that is generated upon irradiation. All tested nanofiber materials exhibited prolonged antibacterial properties, even in the dark after long-duration irradiation. The post-irradiation effect was explained by the photogeneration of H₂O₂, which provided the material with long-lasting antibacterial properties.

Synthesis and Characterization of Waterborne Polyurethane/Cu(II)-Loaded Hydroxyapatite Nanocomposites with Antibacterial Activity

A novel kind of environmentally friendly nanocomposites, waterborne polyurethane (WBPU)/Cu(II)-loaded hydroxyapatite (CuHAp), with improved physical properties and antibacterial activity have been prepared via in-situ polymerization from functionalized CuHAp nanoparticles (CuHAp NPs). The interaction of the CuHAp NPs with isophorone diisocyanate to form the functionalized CuHAp NPs containing isocyanate groups (CuHAp-g-NCO) has been studied. The microstructure and particle distribution of the nanocomposites were observed using scanning electron microscopy. The improvements of mechanical properties, thermal stability and water resistance of the nanocomposites have also been evaluated. Finally, the antibacterial activity was tested against G(-) Escherichia coli and G(+) Staphylococcus aureus by the zone of inhibition test and the direct contact test. The long-lasting antibacterial activity was studied by measuring antibacterial ability of the nanocomposites after being immersed in water. The results indicate that WBPU incorporation with CuHAp NPs shows strong antibacterial activity upon contact, and long-lasting antibacterial property.

Preparation and characterization of polyoxometalate–Ag nanoparticles composite multilayer films

The multifunctional thin films (BW 12/Ag NPs) n (BW 12 = BW 12O 40, NPs = nanoparticles) were prepared by layer-by-layer self-assembly method. The (BW 12/PEI–Ag +) n (PEI = polyethylenimine) composite films were achieved through alternately depositing anionic BW 12 and cationic PEI–Ag + complex. The deposition process of (BW 12/PEI–Ag +) 10 multilayer is linear layer-by-layer self-assembly. Under UV irradiation, Ag ions in (BW 12/PEI–Ag +) n multilayer films were reduced photochemically into Ag NPs and (BW 12/Ag NPs) 10 films were obtained. Through UV–vis measurements, the presence of surface plasma absorption peak at 445 nm demonstrated the formation of silver NPs. The electrochemical and antibacterial activities of (BW 12/Ag NPs) n films were investigated. The electrochemical results indicate that the glassy carbon electrode modified with (BW 12/Ag NP) n film exhibits the electroreduction toward O 2. Moreover, the (BW 12/Ag NP) 10 multilayer films exhibit long-lasting antibacterial properties toward Escherichia coli ( E. coli).

Biocompatibility and antibacterial performance of titanium by surface treatment

Titanium (Ti) and its alloys are used extensively in implants due to their excellent biocompatibility and mechanical properties. However, Ti-based implant materials have specific complications associated with their applications, such as the loosening of implanted host interface owing to unsatisfactory cell adhesion and the susceptibility of the implants to bacterial infections. Hence, a surface that displays selective biointeractivity, i.e., enhancing beneficial host cell responses but inhibiting pathogenic microbial adhesion, would be highly desirable. This study aims to confer long-lasting antibacterial properties and good biocompatibility on Ti via the microarc oxidation technique. The biocompatibility of the Ti surface was evaluated by cytotoxicity test, and the bacteriostasis rate was evaluated by antibacterial efficacy. The results showed that the implant surface might be nontoxic to cell and its long-lasting antibacterial properties could be significantly improved. These results indicate that such microarc oxidation coatings are expected to have good potential in transcutaneous implant applications.

Ocular Surface Distribution and Pharmacokinetics of a Novel Ophthalmic 1% Azithromycin Formulation

To investigate the ocular distribution of 1% azithromycin ophthalmic solution and the effect of polycarbophil-based mucoadhesive formulation on ocular tissue levels of azithromycin after single and multiple topical administrations in the rabbit eye. Rabbits were treated with either a single administration of 1% azithromycin solution with or without polycarbophil, or with multiple administrations of 1% azithromycin solution in polycarbophil. Drug concentrations were measured using LC/MS/MS. Conjunctiva, cornea, aqueous humor, and tear samples were analyzed over a period of 144 h after a single administration of azithromycin with or without polycarbophil. Eyelid, conjunctiva, cornea, aqueous humor, and tear samples were collected over a period of 288 h during and after multiple administrations of azithromycin. Azithromycin was rapidly absorbed and distributed in the ocular tissues, reaching within 5 min, concentrations of 10,539 microg/mL in tear film, 108 microg/g in conjunctiva, and 40 microg/g in the cornea. The drug demonstrated tissue-specific half-lives of 15, 63, and 67 h, respectively. Following multiple administrations, the drug gradually accumulated. The polycarbophil formulation increased the bioavailability of the drug, producing peak concentrations that were between 5- and 12-fold higher than those without polycarbophil. Azithromycin also distributed rapidly in the eyelids, reaching peak concentrations of 180 mug/g at the end of the 7-day treatment, and was eliminated with a half-life of 125 h. Six days after treatment was discontinued, eyelid levels of azithromycin were above 40 microg/g. Sustained and high concentrations were encountered with 7-day approved administration of 1% azithromycin formulation (AzaSite, Inspire Pharmaceuticals, Inc., Durham, NC) within all ocular surface tissues, particularly the lids. Many ocular surface disorders involving the tear film, eyelids, and adnexal structures are associated with chronic, low-grade bacterial infection and may potentially lead to decreased vision secondary to corneal scarring. Various topical antibiotic and steroid combinations with or without oral tetracyclines are commonly used with variable clinical response and known potential side effects. The clinical relevance of this study is unknown; however, the long-lasting antibacterial and additional anti-inflammatory properties of topical azithromycin might offer an effective alternative treatment option and should be explored further in clinical studies.

Surface functionalization of titanium with hyaluronic acid/chitosan polyelectrolyte multilayers and RGD for promoting osteoblast functions and inhibiting bacterial adhesion

Titanium (Ti) and its alloys are used extensively in orthopedic implants due to their excellent biocompatibility and mechanical properties. However, titanium-based implant materials have specific complications associated with their applications, such as the loosening of implant–host interface owing to unsatisfactory cell adhesion and the susceptibility of the implants to bacterial infections. Hence, a surface which displays selective biointeractivity, i.e. enhancing beneficial host cell responses but inhibiting pathogenic microbial adhesion, would be highly desirable. This present study aims to improve biocompatibility and confer long-lasting antibacterial properties on Ti via polyelectrolyte multilayers (PEMs) of hyaluronic acid (HA) and chitosan (CH), coupled with surface-immobilized cell-adhesive arginine-glycine-aspartic acid (RGD) peptide. The HA/CH PEM-functionalized Ti is highly effective as an antibacterial surface but the adhesion of bone cells (osteoblasts) is poorer than on pristine Ti. With additional immobilized RGD moieties, the osteoblast adhesion can be significantly improved. The density of the surface-immobilized RGD peptide has a significant effect on osteoblast proliferation and alkaline phosphatase (ALP) activity, and both functions can be increased by 100–200% over that of pristine Ti substrates while retaining high antibacterial efficacy. Such substrates can be expected to have good potential in orthopedic applications.

Antimicrobial polyethylene with controlled copper release

Good antiinfection properties of medical polymers, especially those used in artificial organs, are crucial to the minimization of microbial attack in nosocomial treatments. However, medical polymers fabricated by conventional methods usually have unstable and short-lived antimicrobial effects because of unsteady out-diffusion of the antibacterial species from the organic matrix. Here, we introduce a dual plasma implantation process to enhance the properties. An inorganic antibacterial element, copper, is introduced into a medical polymer, polyethylene (PE), by means of copper plasma immersion ion implantation (PIII) and a subsequent nitrogen PIII process is used to regulate the release of the implanted Cu. X-ray photoelectron spectroscopy and transmission electron microscopy reveal that a relatively large amount of copper of about 11% is implanted into PE to a depth of several hundred nanometers. Chemical analyses confirm that the implanted Cu does not bond with the polymer matrix. However, the N(2) plasma treatment produces various functional bonds such as C=N, and C[triple bond]N which exert appreciable influence on regulating the out-diffusion rate of copper. The large amount of embedded Cu, coupled with controlled release of the element to the surface, gives rise to excellent and long-lasting surface antibacterial properties of the plasma-treated polymer. The capability of controlling the release and storing the antibacterial reagent in a buried layer leads to better antimicrobial polymeric materials for medicine.

Antibacterial properties of self-etching dental adhesive systems

Dental adhesives with antibacterial properties may reduce recurrent or secondary caries. The authors conducted a study to examine the immediate and long-lasting antibacterial properties of four self-etching adhesive systems. The authors used the agar diffusion test (ADT) and direct contact test (DCT) to measure the antibacterial properties of AdheSe (Ivoclar Vivadent, Schaan, Liechtenstein), Adper Prompt L-Pop (3M ESPE, Seefeld, Germany), Clearfil Protect Bond (Kuraray, Kurashiki, Okayama, Japan) and Xeno III (Dentsply, Konstanz, Germany) on Streptoccocus mutans after aging samples in phosphate-buffered saline for one, two, seven and 14 days. Only Clearfil Protect Bond showed an inhibition halo in the ADT. In the DCT, fresh samples of all of the tested materials exhibited potent antibacterial properties, which were maintained by AdheSe for one day and Clearfil Protect Bond for seven days. None of the adhesive systems exhibited any antibacterial properties after 14 days. All of the tested adhesives had an immediate bactericidal effect on S. mutans. None, however, had long-lasting antibacterial properties. The application of self-etching adhesive materials could contribute to the immediate elimination of residual bacteria. The likelihood of developing secondary caries as a consequence of bacterial microleakage may not be affected by the use of the adhesive systems tested in this study.

Antibacterial properties of 4 orthodontic cements

White spot lesions are observed in nearly 50% of patients undergoing orthodontic treatment. Long-lasting antibacterial properties of orthodontic cements can reduce this phenomenon. The antibacterial properties of 4 orthodontic cements were evaluated by direct contact test (DCT) and agar diffusion test (ADT). With the DCT technique, octet specimens of glass ionomer (CX-Plus; Shofu, Kyoto, Japan), reinforced glass ionomer (GC Fuji ORTHO LC; GC Corporation, Tokyo, Japan), and 2 composite (Transbond XT and Transbond Plus; 3M Unitek, Monrovia, Calif) orthodontic cements were placed on the sidewalls of wells of a 96-microtiter plate. Streptococcus mutans cells (ca. 1 x 10(6) ) were placed on the surface of each specimen for 1 hour at 37 degrees C. Then, fresh media was added to each well, and bacterial growth was monitored for 16 hours with a temperature-controlled spectrophotometer. This was repeated on specimens aged in phosphate-buffered saline for 1 day, 1 week, and 1 month. The ADT was performed by placing specimens in wells punched in agar plates. Measurement of the halo in bacterial lawn after 48 hours showed that only the glass ionomer cement (CX-Plus) produced an inhibition zone (1.2 mm around the sample). Results at the DCT showed that only the reinforced glass ionomer cement (GC Fuji ORTHO LC) exhibited potent antibacterial activity, which lasted 1 week and diminished over the next 3 weeks. The reinforced glass ionomer cement possessed the most potent and long-lasting antibacterial activity.

Antibacterial and antifungal efficacy of surface functionalized polymeric beads in repeated applications

A simple method was developed to prepare polymeric microbeads with antibacterial and antifungal properties. The microbeads of approximately spherical shape and narrow size distribution were prepared from a mixture of poly (4-vinyl pyridine) (P4VP) and poly (vinylidene fluoride) (PVDF) by a phase inversion technique and subsequently derivatized with alkyl bromides having 4-10 carbon atoms. The quaternization of the pyridine groups into pyridinium groups confers the surface with highly effective and long-lasting antibacterial and antifungal properties, as shown by the effect on Escherichia coli and Aspergillus niger. Upon contact with the N-alkylated beads, the bacteria and fungal spores are lysed and intracellular constituents leach out into the medium. The efficacy of the alkyl chains in disrupting the cell membrane was investigated. The stability of the functional group and microbiocidal effectiveness of the microbeads in repeated applications was also assessed.

Prevention of Catheter-Related Infections by Antiseptic Bonding

A novel catheter pretreated with the antiseptics chlorhexidine and silver-sulfadiazine, designed to reduce catheter-related colonization and infection, was tested in both in vitro and in vivo studies. In vitro experiments demonstrated the long-lasting antibacterial properties of this catheter. For the in vivo study a total of 40 rats divided into different experimental groups were used. Colonization rates of both antiseptic bonded (AS) and control (C) catheters were assessed either three (-3) or seven (-7) days after implantation and local challenge using live Staphylococcus epidermidis ATCC 35984 with 107 colony-forming units (cfu) per inoculum. At the time of removal, catheters, organ specimens, and blood samples were taken for cultivation. Significant reductions in the magnitude of colonization of the antiseptic catheters by the test organism were observed in all groups. The average number of cfu colonizing control segments exceeded those found on the treated catheter segments by log 3 (C3/AS3) and log 5 (C7/AS7), respectively (C3:1.2 × 106 ± 4.1 × 105 cfu/segment and AS3:1.8 × 103 ± 6.6 × 102;C7:2.7 × 105 ± 8.6 × 104 and AS7: 1.1 ± 0.7; mean ± standard error of the mean, all differences between matching groups statistically significant, Wilcoxon rank sum test, P < 0.0001). These data suggest that antiseptic catheters may substantially decrease the magnitude of catheter-related microbial colonization and subsequent catheter-related infections and may offer a more effective alternative to current methods.