Differences In Bacterial Adhesion Research Articles

Difference in formation of a dental multi-species biofilm according to substratum direction

ObjectivesThe aim of this study was to investigate the difference in dental biofilm formation according to substratum direction, using an artificial biofilm model. MethodsA three-species biofilm, consisting of Streptococcus mutans, Streptococcus oralis, and Actinomyces naeslundii, was formed on saliva-coated hydroxyapatite (sHA) discs oriented in three directions: downward (the discs placed in the direction of gravity), vertical (the discs placed parallel to the direction of gravity), and upward (the discs placed in opposite direction of gravity). The biofilms at 22 h and 46 h of age were analyzed using microbiological and biochemical methods, fluorescence-based assays, and scanning electron microscopy to investigate difference in bacterial adhesion, early and mature biofilm formation. ResultsThe biofilms formed in the upward direction displayed the most complex structure, with the highest number and biovolume of bacteria, as well as the lowest pH conditions at both time points. The vertical and downward directions, however, had only scattered and small bacterial colonies. In the 22-h-old biofilms, the proportion of S. oralis was similar to, or slightly higher than, that of S. mutans in all directions of substratum surfaces. However, in the 46-h-old biofilms, S. mutans became the dominant bacteria in all directions, especially in the vertical and upward directions. ConclusionsThe direction of the substratum surface could impact the proportion of bacteria and cariogenic properties of the multi-species biofilm. Biofilms in an upward direction may exhibit a higher cariogenic potential, followed by those in the vertical and downward directions, which could be related to gravity.

Bacterial adhesion inhibition by microalgal EPSs from Cylindrotheca closterium and Tetraselmis suecica biofilms.

In the food industry, successful bacterial pathogen colonization and persistence begin with their adhesion to a surface, followed by the spatial development of mature biofilm of public health concerns. Compromising bacterial settlement with natural inhibitors is a promising alternative to conventional anti-fouling treatments typically based on chemical biocides that contribute to the growing burden of antimicrobial resistance. In this study, three extracellular polymeric substance (EPS) fractions extracted from microalgae biofilms of Cylindrotheca closterium (fraction C) and Tetraselmis suecica (fraction Ta rich in insoluble scale structure and fraction Tb rich in soluble EPS) were screened for their anti-adhesive properties, against eight human food-borne pathogens belonging to Escherichia coli, Staphylococcus aureus, Salmonella enterica subsp. enterica, and Listeria monocytogenes species. The results showed that the fraction Ta was the most effective inducing statistically significant reduction for three strains of E. coli, S. aureus, and L. monocytogenes. Overall, EPSs coating on polystyrene surfaces of the different fractions increased the hydrophilic character of the support. Differences in bacterial adhesion on the different coated surfaces could be explained by several dissimilarities in the structural and physicochemical EPS compositions, according to HPLC and ATR-FTIR analysis. Interestingly, while fractions Ta and Tb were extracted from the same microalgal culture, distinct adhesion patterns were observed, highlighting the importance of the extraction process. Overall, the findings showed that EPS extracted from microalgal photosynthetic biofilms can exhibit anti-adhesive effects against food-borne pathogens and could help develop sustainable and non-toxic anti-adhesive surfaces for the food industry. KEY POINTS: •EPSs from a biofilm-based culture of C. closterium/T. suecica were characterized. •Microalgal EPS extracted from T. suecica biofilms showed bacterial anti-adhesive effects. •The anti-adhesive effect is strain-specific and affects both Gram - and Gram + bacteria.

Bacterial Adhesion of TESPSA and Citric Acid on Different Titanium Surfaces Substrate Roughness: An In Vitro Study with a Multispecies Oral Biofilm Model.

This in vitro study analyzed the influence of substrate roughness on biofilm adhesion and cellular viability over triethoxysilylpropyl succinic anhydride silane (TESPSA)- and citric acid (CA)-coated surfaces at 12 and 24 h, respectively. A multispecies biofilm composed of S. oralis, A. naslundii, V. parvula, F. nucleatum, P. intermedia, P. gingivalis, P. endodontalis and F. alocis was developed over titanium discs grouped depending on their roughness (low, medium, high) and antibacterial coating (low-TESPSA, medium-TESPSA, high-TESPSA, and CA). The biofilm was quantified by means of quantitative polymerase chain reaction (PCR) and viability PCR and assessed through confocal laser scanning microscope (CLSM). Quantitative PCR revealed no significant differences in bacterial adhesion and biofilm mortality. CA was the surface with the lowest bacterial counts and highest mortality at 12 and 24 h, respectively, while high harbored the highest amount of biofilm at 24 h. By CLSM, CA presented significant amounts of dead cells compared to medium-TESPSA and high-TESPSA. A significantly greater volume of dead cells was found at 12 h in low-TESPSA compared to medium-TESPSA, while CA also presented significant amounts of dead cells compared to medium-TESPSA and high-TESPSA. With regard to the live/dead ratio, low-TESPSA presented a significantly higher ratio at 12 h compared to medium-TESPSA and high-TESPSA. Similarly, CA exhibited a significantly higher live/dead ratio compared to medium-TESPSA and high-TESPSA at 12 h. This multispecies in vitro biofilm did not evidence clear antiadhesive and bactericidal differences between surfaces, although a tendency to reduce adhesion and increase antibacterial effect was observed in the low-TESPSA and CA.

PD28-06 URETERAL STENT BIOMATERIAL ENCRUSTATION AFTER ENDOSCOPIC SURGERY: A PROSPECTIVE, RANDOMIZED STUDY

You have accessJournal of UrologyCME1 Apr 2023PD28-06 URETERAL STENT BIOMATERIAL ENCRUSTATION AFTER ENDOSCOPIC SURGERY: A PROSPECTIVE, RANDOMIZED STUDY Shuzo Hamamoto, Ryosuke Chaya, Koei Torii, Masahiko Isogai, Kengo Kawase, Teruaki Sugino, Rei Unno, Kazumi Taguchi, Atsushi Okada, and Takahiro Yasui Shuzo HamamotoShuzo Hamamoto More articles by this author , Ryosuke ChayaRyosuke Chaya More articles by this author , Koei ToriiKoei Torii More articles by this author , Masahiko IsogaiMasahiko Isogai More articles by this author , Kengo KawaseKengo Kawase More articles by this author , Teruaki SuginoTeruaki Sugino More articles by this author , Rei UnnoRei Unno More articles by this author , Kazumi TaguchiKazumi Taguchi More articles by this author , Atsushi OkadaAtsushi Okada More articles by this author , and Takahiro YasuiTakahiro Yasui More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003313.06AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Ureteral stents are commonly used in endoscopic surgery for urinary calculi but are frequently associated with stent encrustation and stent-related infections. New biomaterials and coatings have been designed to overcome these disadvantages. However, there are no real-world reports comparing biomaterial encrustation of different stents. In this study, we prospectively evaluated the adherence of bacteria, Ca, and Mg to three different ureteral stents after endoscopic surgery for urinary calculi. METHODS: A total of 61 patients requiring insertion of ureteral stents after the treatment of urinary calculi were randomly placed into 3 groups [Percuflex with a coating composition of Hydroplus, Group 1 (n=21); Tria, with a coating composition of Percushied, Group 2 (n=22); InLay Optima, which had a proprietary pHreeCoat coating, Group 3 (n=18)]. All stents were removed one month after treatment and evaluated. A stent was immersed in a solution of saline and hydrochloric acid at pH 2 and subsequently vortexed for one hour. Ca and Mg contents were measured using atomic absorption spectrometry. Bacteria were measured using flow cytometry. RESULTS: There were no significant differences about patients and stone characteristics. The incidence of stone encrustation was significantly higher in Group 1 than in Groups 2 and 3 (33.3%, 11.7%, and 7.7%, respectively; p=0.02). The median amount (IQR) of Ca adhered to the stents in Group 1 was significantly higher than that in Groups 2 and 3 (5.51 (2.28-6.18), 1,91 (0.53-4.48), 2.30 (0.76-3.03) mg/dL respectively, p=0.024). The median amount (IQR) of Mg in Group 1 was sig nificantly higher than that in Groups 2 and 3 (0.20 (0.15-0.23), 0.06 (0.04-0.20), 0.03 (0.03-0.13) mg/dL respectively, p=0.005). The median number (IQR) of bacteria was also highest in Group 1 (33.76 (23.13-109.43), 13.80 (6.23-56.25), 8.33 (6.80-21.20), respectively, p=0.056); however, there were no significant differences in bacterial adhesion. CONCLUSIONS: This randomized study showed that stents with Percusheild coating and pHreeCoat coating decreased the adherence of Ca, Mg after endoscopic treatment. These stents could reduce stent encrustation and stent-related infections. Source of Funding: none © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e820 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Shuzo Hamamoto More articles by this author Ryosuke Chaya More articles by this author Koei Torii More articles by this author Masahiko Isogai More articles by this author Kengo Kawase More articles by this author Teruaki Sugino More articles by this author Rei Unno More articles by this author Kazumi Taguchi More articles by this author Atsushi Okada More articles by this author Takahiro Yasui More articles by this author Expand All Advertisement PDF downloadLoading ...

Bacterial adhesion and antibacterial property of coating materials containing theobromine and S-PRG filler.

Theobromine (TB) has been reported to promote tooth remineralization, strengthen tooth substance, and relieve dentin hypersensitivity. This study aimed to evaluate experimental tooth coating materials containing TB and surface pre-reacted glass-ionomer (S-PRG) fillers by examining the effects on bacterial adhesion and antibacterial properties. In addition, the amount of TB eluted from the coating material was measured. There was no significant difference in bacterial adhesion depending on the presence or absence of TB in the coating material, however, a significant decrease in the amount of bacterial adhesion was observed when S-PRG fillers were added to the coating material. The amount of eluted TB did not differ depending on the type of the filler in the coating material. It was suggested that TB could be used to develop a new dental material with the potential ability to inhibit the initiation and progression of dental caries.

Impact of physical decontamination methods on zirconia implant surface and subsequent bacterial adhesion: An in-vitro study.

ObjectiveTo evaluate the effect of routinely used physical decontamination methods on the surface characteristics of zirconia implants and subsequent ability of bacteria to adhere in vitro.BackgroundPhysical decontamination methods commonly used in peri‐implantitis therapy and routine implant maintenance can potentially alter zirconia implant surfaces.MethodsAcid‐etched zirconia discs were instrumented with titanium curette (TC), plastic curette, air abrasive device, ultrasonic scaler (US) with stainless steel tip. Following instrumentation, surface topography, and surface elemental composition was analyzed using 3D‐laser scanning microscopy and energy‐dispersive X‐ray spectroscopy, respectively. Subsequently, plaque biofilm was cultured on zirconia discs for 48 h and bacterial adhesion assessed using a turbidity test and scanning electron microscopy.ResultsA significant difference in surface roughness was observed between the US and control group (p < 0.05). The US and TC caused gray surface discolouration on zirconia discs due to deposition of metallic residue as confirmed by X‐ray spectroscopy. No significant difference in bacterial adhesion was noted among all treatment groups (p > 0.05).ConclusionTC and US with stainless steel tips should be used with caution due to deposition of metallic residue on the surface. Air abrasive devices and plastic curettes caused minimal surface alterations and are, therefore, safer for zirconia implant decontamination.

PD26-01 A PROSPECTIVE, RANDOMIZED, SINGLE-BLIND COMPARISON OF URETERAL STENT BIOMATERIAL ENCRUSTATION

You have accessJournal of UrologyStone Disease: Surgical Therapy III (PD26)1 Sep 2021PD26-01 A PROSPECTIVE, RANDOMIZED, SINGLE-BLIND COMPARISON OF URETERAL STENT BIOMATERIAL ENCRUSTATION Shuzo Hamamoto, Ryosuke Chaya, Masahiko Isogai, Kengo Kawase, Tomoki Okada, Tatsuya Hattori, Teruaki Sugino, Rei Unno, Kazumi Taguchi, Atsushi Okada, and Takahiro Yasui Shuzo HamamotoShuzo Hamamoto More articles by this author , Ryosuke ChayaRyosuke Chaya More articles by this author , Masahiko IsogaiMasahiko Isogai More articles by this author , Kengo KawaseKengo Kawase More articles by this author , Tomoki OkadaTomoki Okada More articles by this author , Tatsuya HattoriTatsuya Hattori More articles by this author , Teruaki SuginoTeruaki Sugino More articles by this author , Rei UnnoRei Unno More articles by this author , Kazumi TaguchiKazumi Taguchi More articles by this author , Atsushi OkadaAtsushi Okada More articles by this author , and Takahiro YasuiTakahiro Yasui More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002019.01AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Ureteral stents are commonly used in endoscopic surgery for urinary calculi but are frequently associated with stent encrustation and stent-related infections. New biomaterials and coatings have been designed to overcome these disadvantages. However, there are no real-world reports comparing biomaterial encrustation of different stents. In this study, we prospectively evaluated the adherence of bacteria, Ca, and Mg to three different ureteral stents after endoscopic surgery for urinary calculi. METHODS: A total of 61 patients requiring insertion of ureteral stents after the treatment of urinary calculi were randomly placed into 3 groups [PercuflexⓇ with a coating composition of Hydroplus, Group 1 (n=21); Tria, with a coating composition of PercushiedⓇ, Group 2 (n=22); InLay OptimaⓇ, which had a proprietary pHreeCoat coating, Group 3 (n=18)]. All stents were removed one month after treatment and evaluated. A stent was immersed in a solution of saline and hydrochloric acid at pH 2 and subsequently vortexed for one hour. Ca and Mg contents were measured using atomic absorption spectrometry. Bacteria were measured using flow cytometry. RESULTS: There were no significant differences about patients and stone characteristics. The incidence of stone encrustation was significantly higher in Group 1 than in Groups 2 and 3 (33.3%, 11.7%, and 7.7%, respectively; p=0.02). The median amount (IQR) of Ca adhered to the stents in Group 1 was significantly higher than that in Groups 2 and 3 (5.51 (2.28-6.18), 1,91 (0.53-4.48), 2.30 (0.76-3.03) mg/dL respectively, p=0.024). The median amount (IQR) of Mg in Group 1 was significantly higher than that in Groups 2 and 3 (0.20 (0.15-0.23), 0.06 (0.04-0.20), 0.03 (0.03-0.13) mg/dL respectively, p=0.005). The median number (IQR) of bacteria was also highest in Group 1 (33.76 (23.13-109.43), 13.80 (6.23-56.25), 8.33 (6.80-21.20), respectively, p=0.056); however, there were no significant differences in bacterial adhesion. CONCLUSIONS: This randomized study showed that stents with Percusheild coating and pHreeCoat coating decreased the adherence of Ca, Mg after endoscopic treatment. These stents could reduce stent encrustation and stent-related infections. Source of Funding: none © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e437-e437 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Shuzo Hamamoto More articles by this author Ryosuke Chaya More articles by this author Masahiko Isogai More articles by this author Kengo Kawase More articles by this author Tomoki Okada More articles by this author Tatsuya Hattori More articles by this author Teruaki Sugino More articles by this author Rei Unno More articles by this author Kazumi Taguchi More articles by this author Atsushi Okada More articles by this author Takahiro Yasui More articles by this author Expand All Advertisement Loading ...

Examination of Streptococcus Mutans Adhesion in Current Hybrid Ceramics and Composites

This study evaluated the surface topography and bacterial adhesion of a different hybrid ceramics and resin composites after optimal surface finishes. A total of disk samples were prepared using two different CAD/CAM blocks [Vita Enamic (VE), Shofu HC (SHC)] and two different composites [Tetric N Ceram bulk-fill (TNC), Estelite Sigma Quick (ESQ)] with diameter 10 mm and thickness 4.0 ± 0.2mm. Fifteen disc samples were produced for each group (n=15). Surfaces of the sample disks were polished according to the manufacturer’s recommendations with the specially produced polish sets. The surface roughness of specimens was analyzed parameter (Ra), sterilized, and subjected to bacterial adhesion. Data were submitted to one-way ANOVA and Tukey’s test (α= 0.05). TNC and ESQ groups had lower surface roughness than VE and SHC groups (p<0.05). There was no difference in bacterial adhesion between hybrid CAD/CAM blocks and composite materials. The material type and surface finishing system did not significantly interfere with surface roughness parameters and bacterial adhesion. The surface polishing of nanocomposite resins performed is better than hybrid ceramic after polishing. An adequate finishing/polishing technique should always be applied after any adjustments made to indirect restorations with these materials tested. There is no difference between bacterial adhesions of the tested materials. If appropriate and sufficient, polishing is performed.

Antibacterial properties of metal and PDMS surfaces under weak electric fields

The adhesion of several species of bacteria on two parallel rectangular electrodes under weak electric fields was studied. The electrodes were based on native metal or PDMS coated Cu. After 2 h of contact at a voltage of 0.2 to 1 V without any current, the Zn cathode showed a bacterial repellent effect with a difference in bacterial adhesion of about 1.5 to 2 log CFU/cm2 on the anode. Al electrodes were inactive due to their passivation by the alumina layer. At 1 V, both Zn and Al exhibited more than 80% mortality of suspended bacteria. The Cu electrodes showed a very high bactericidal effect even at 0 V, and the bacterial adhesion on its surface was too weak to see a difference between the two electrodes. A similar study carried out on PDMS surfaces, covering Cu electrodes, revealed that a difference of 1 log CFU/cm2 of bacterial adhesion between the cathode and anode surfaces can be obtained by applying a voltage ranging from 10 to 30 V. This cathodic repellent effect was specific to staphylococcus species, suggesting that in the presence of a PDMS coating, the electrostatic forces on the surface are too low to be the main factor governing bacterial adhesion.

A Photoswitchable Trivalent Cluster Mannoside to Probe the Effects of Ligand Orientation in Bacterial Adhesion.

We have recently demonstrated, by employing azobenzene glycosides, that bacterial adhesion to surfaces can be switched through reversible reorientation of the carbohydrate ligands. To investigate this phenomenon further, we have turned here to more complex-that is, multivalent-azobenzene glycoclusters. We report on the synthesis of a photosensitive trivalent cluster mannoside conjugated to an azobenzene hinge at the focal point. Molecular dynamics studies suggested that this cluster mannoside, despite the conformational flexibility of the azobenzene-glycocluster linkage, offers the potential for reversibly changing the glycocluster's orientation on a surface. Next, the photoswitchable glycocluster was attached to human cells, and adhesion assays with type 1 fimbriated Escherichia coli bacteria were performed. They showed marked differences in bacterial adhesion, dependent on the light-induced reorientation of the glycocluster moiety. These results further underline the importance of orientational effects in carbohydrate recognition and likewise the value of photoswitchable glycoconjugates for their study.

Fabrication and Hydrodynamic Characterization of a Microfluidic Device for Cell Adhesion Tests in Polymeric Surfaces.

A fabrication method is developed to produce a microfluidic device to test cell adhesion to polymeric materials. The process is able to produce channels with walls of any spin coatable polymer. The method is a modification of the existing poly-dimethylsiloxane soft lithography method and, therefore, it is compatible with sealing methods and equipment of most microfluidic laboratories. The molds are produced by xurography, simplifying the fabrication in laboratories without sophisticated equipment for photolithography. The fabrication method is tested by determining the effective differences in bacterial adhesion in five different materials. These materials have different surface hydrophobicities and charges. The major drawback of the method is the location of the region of interest in a lowered surface. It is demonstrated by bacterial adhesion experiments that this drawback has a negligible effect on adhesion. The flow in the device was characterized by computational fluid dynamics and it was shown that shear stress in the region of interest can be calculated by numerical methods and by an analytical equation for rectangular channels. The device is therefore validated for adhesion tests.

The "Race for the Surface" experimentally studied: In vitro assessment of Staphylococcus spp. adhesion and preosteoblastic cells integration to doped Ti-6Al-4V alloys.

Implant-related infection is a devastating complication in orthopedic surgery. Aiming to minimize this problem, many material modifications have been developed. Here we report a study of a surface modification of Ti-6 Al-4 V alloy using a methodology that enables the study of interactions between bacteria and the material in the presence of eukaryotic cells. We mixed different concentrations of collection or clinical strains of staphylococci isolated from implant-related infections with preosteoblastic cells using a previously published methodology, analyzing the minimal concentration of bacteria able to colonize the surface of the material through image analysis. Ti-6 Al-4 V alloy was modified by anodization to obtain two F-doped nanostructured surfaces that have been previously described to have antibacterial properties. Our results show similar bacterial adhesion results to nanoporous and nanotubular F-doped surfaces. The presence of preosteoblastic cells increases the adherence of all bacterial strains to both structures. No effect of the surface on eukaryotic cells adherence was detected. To our knowledge, this is the first time that anin vitro study emulating the race for the surface evaluates and compares the osseointegration and antibacterial properties between two nanostructured- modified titanium alloy surfaces. Clinical strains show different behavior from collection ones in bacterial adherence. The presence of cells increased bacterial adherence. NP and NT surface modifications didn´t show significant differences in bacterial adhesion and preosteoblastic cells integration.

Antimicrobial Activity of Chlorhexidine against Multi-Species Biofilm Formation

In the present work, the efficacy of the Ti–7.5Mo alloy nanotube and Ti–7.5Mo alloy nanotube with chlorhexidine against bacterial biofilm formation was evaluated. Nanotubes were processed using anodization in 0.25% NH4F electrolyte solution. Biofilms were cultured in discs immersed in sterile brain heart infusion broth (BHI) containing 5% sucrose, inoculated with microbial suspension (106 cells/ml) and incubated for 5 days. Next, the discs were placed in tubes with sterile physiological solution 0.9% sodium chloride (NaCl) and sonicated to disperse the biofilms. Tenfold serial dilutions were carried and aliquots seeded in selective agar, which were then incubated for 48 h. Then, the numbers CFU/ml (log 10) were counted and analyzed statistically. Scanning electron microscopy (SEM) on discs with biofilms groups and contact angle was carried out. The results show that there is no difference in bacterial adhesion between of the Ti–7.5Mo alloy nanotube and Ti–7.5Mo alloy nanotube with chlorhexidine.

Effect of polishing method on surface roughness and bacterial adhesion of zirconia-porcelain veneer

The purpose of this study was to evaluate the effect of various polishing methods on surface roughness of zirconia-porcelain veneer and to correlate the findings with early bacterial adhesion. The study specimens were glazed (control group), glazed after fine polishing (glazed group) and polished with Exa Cerapol (Cerapol group) or with Shofu porcelain adjustment kit (Shofu group) (n =20). Surface roughness was then measured using profilometer and scanning electron microscope (SEM). After artificial saliva coating, the specimens were incubated in Streptococcus mitis suspension for 4h at 37°C. Adherent bacteria were quantified from SEM images. Streptococcal viability was assessed by LIVE/DEAD staining kit and fluorescent microscope. There were significant differences in surface roughness according to polishing method and surface material. Relatively smoother surfaces were found in zirconia surfaces and glazed porcelain surfaces. There were also significant differences in bacterial adhesion according to polishing method and surface material. Cerapol group showed minimal bacterial adhesion with more dead cells when compared to other groups. A positive correlation between surface roughness and bacterial adhesion was found in glazed porcelain surface and a negative correlation in zirconia surface of Cerapol group, both with no statistical significance. Within the limitations of in vitro study, surface roughness and bacteria adhesion were significantly influenced by polishing method and surface material. Also, there was a positive correlation and negative correlation between surface roughness and bacterial adhesion in glazed porcelain surface and in zirconia surface of Cerapol group, respectively.

Effect of a static magnetic field on Escherichia coli adhesion and orientation.

This preliminary study focused on the effect of exposure to 0.5 T static magnetic fields on Escherichia coli adhesion and orientation. We investigated the difference in bacterial adhesion on the surface of glass and indium tin oxide-coated glass when exposed to a magnetic field either perpendicular or parallel to the adhesion surface (vectors of magnetic induction are perpendicular or parallel to the adhesion surface, respectively). Control cultures were simultaneously grown under identical conditions but without exposure to the magnetic field. We observed a decrease in cell adhesion after exposure to the magnetic field. Orientation of bacteria cells was affected after exposure to a parallel magnetic field. On the other hand, no effect on the orientation of bacteria cells was observed after exposure to a perpendicular magnetic field.

ATR–FTIR spectroscopic evidence for biomolecular phosphorus and carboxyl groups facilitating bacterial adhesion to iron oxides

Attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopy has been used to probe the binding of bacteria to hematite (α-Fe2O3) and goethite (α-FeOOH). In situ ATR–FTIR experiments with bacteria (Pseudomonas putida, Pseudomonas aeruginosa, Escherichia coli), mixed amino acids, polypeptide extracts, deoxyribonucleic acid (DNA), and a suite of model compounds were conducted. These compounds represent carboxyl, catecholate, amide, and phosphate groups present in siderophores, amino acids, polysaccharides, phospholipids, and DNA. Due in part to the ubiquitous presence of carboxyl groups in biomolecules, numerous IR peaks corresponding to outer-sphere or unbound (1400cm−1) and inner-sphere (1310–1320cm−1) coordinated carboxyl groups are noted following reaction of bacteria and biomolecules with α-Fe2O3 and α-FeOOH. However, the data also reveal that the presence of low-level amounts (i.e., 0.45–0.79%) of biomolecular phosphorous groups result in strong IR bands at ∼1043cm−1, corresponding to inner-sphere FeOP bonds, underscoring the importance of bacteria associated P-containing groups in biomolecule and cell adhesion. Spectral comparisons also reveal slightly greater POFe contributions for bacteria (Pseudomonad, E. coli) deposited on α-FeOOH, as compared to α-Fe2O3. This data demonstrates that slight differences in bacterial adhesion to Fe oxides can be attributed to bacterial species and Fe-oxide minerals. However, more importantly, the strong binding affinity of phosphate in all bacteria samples to both Fe-oxides results in the formation of inner-sphere FeOP bonds, signifying the critical role of biomolecular P in the initiation of bacterial adhesion.

Sm:HAp Nanopowders Present Antibacterial Activity against Enterococcus faecalis

The synthesis of nanoparticles with inhibitory and bactericidal effects represents a great interest in development of new materials for biological applications. In this paper we present for the first time the synthesis of nanoparticles at low temperature and primary tests concerning the adherence of Enterococcus faecalis ATCC 29212 (gram‐positive bacteria). All the XRD peaks were indexed in accordance with the hexagonal HAp in P63m space group. The EDAX spectrum and elemental mapping of O, P, Ca, and Sm demonstrate that all the elements were homogeneously distributed in with xSm = 0.03. The peaks at 347.3 eV, 532.1 eV, and 133.8 eV in the XPS spectra can be attributed to the binding energy of Ca 2p, O 1s, and P 2p. The peak at 1084.4 eV observed in was attributed to the Sm 3d5/2. Bacterial adhesion was reduced on sample when compared to pure HAp (xSm = 0) and significant differences in bacterial adhesion on pure HAp (x = 0) and Sm:HAp (xSm = 0.01, xSm = 0.03, and xSm = 0.1) were observed. The bacterial adhesion decreased when the samarium concentrations increased. Finally, we demonstrate that the Sm:HAp nanopowder with xSm &gt; 0 showed high antibacterial activity against Enterococcus faecalis ATCC 29212.

Adhesion of Streptococci to various orthodontic composite resins

This investigation aimed to determine quantitatively the adhesion of Streptococcus mutans and Streptococcus sobrinus to orthodontic composite resins that were tested simultaneously using radio-markers. Seven orthodontic composite resins were classified into seven groups: BeautyOrtho Bond (GI), Blugloo (GII), Enlight (GIII), Grengloo (GIV), Kurasper F (GV), Transbond CC (GVI) and Turbo Bond II (GVII). Thirty 4 x 4 x 1 mm blocks of each orthodontic composite resin were made (a total of 210 blocks). Both Streptococcus species were cultivated independently. For the quantitative analysis, radioactive markers were used to codify the bacteria ((3) H for Streptococcus mutans and (14) C for Streptococcus sobrinus). The blocks were submerged in a solution with microorganisms previously radiolabelled for 2 hours at 37°C in constant movement. The blocks were placed in a combustion system to quantify the Streptococcus adhering to the surface of the materials by capturing the residues and measuring the radiation. Significant differences in bacterial adhesion were found among the groups. The lowest significant scores for both microorganisms were observed in GIII. The orthodontic composite resin evaluated in GIII exhibited the lowest adhesion of Streptococcus mutans and Streptococcus sobrinus, which may reduce enamel demineralization and the risk of white spot lesion formation.

Effect of Osteopontin on the Initial Adhesion of Dental Bacteria

Bacterial biofilms are involved in numerous infections of the human body, including dental caries. While conventional therapy of biofilm diseases aims at eradication and mechanical removal of the biofilms, recent therapeutic approaches target the mechanisms of biofilm formation and bacterial adhesion in particular. The effect of bovine milk osteopontin, a highly phosphorylated whey protein, on adhesion of Streptococcus mitis, Streptococcus sanguinis, and Actinomyces naeslundii, three prominent colonizers in dental biofilms, to saliva-coated surfaces was investigated. While adhesion of A. naeslundii was not affected by osteopontin, a strong, dose-dependent reduction in the number of adhering S. mitis was shown. No difference in bacterial adhesion was observed for caseinoglycomacropeptide, another phosphorylated milk protein. Osteopontin did not affect bacterial viability, but changed bacterial surface hydrophobicity, and may be suggested to prevent the adhesins of S. mitis from interacting with their salivary receptors. The antiadhesive effect of osteopontin may be useful for caries prevention.

Evaluation of Bacterial Adhesion on Machined Titanium, Osseotite® and Nanotite® Discs

Bacterial adhesion and colonization play a crucial function in the pathogenesis of peri-implant tissue infection, which is considered the main cause of fixture loss. The aim of this study is to evaluate the differences in bacterial adhesion between a machined titanium surface, a double acid etched surface (Osseotite®) and an Osseotite surface with Nanometer-scale Discrete Crystalline Deposition (DCD™) of calcium phosphate (CaP)(Nanotite®). Surface roughness properties of each sample were determined by a laser profilometer and scanning electron microscopy (SEM) observation. Bacterial adhesion on machined, Osseotite®, and Nanotite® discs were performed using the following bacterial strains: Streptococcus mutans CCUG 35176, Streptococcus sanguis CCUG 17826, Streptococcus salivarius CCUG 11878, Actinobacillus actinomycetecomitans CCUG 37002, Porphyromonas gingivalis CCUG 2521. The assessment of bacterial adhesion was performed by comparing two methods: Total Viable Count (TVC) estimation and Confocal Laser Scanning Microscopic (CSLM) studies. The surface roughness parameter increased as follows: machined<Nanotite®<Osseotite®. The attachment of all bacterial strains performed by both methods showed a significant reduction on Osseotite® and even higher on Nanotite® in comparison to machined surfaces (p<0.05). The reduction in bacterial attachment was more significant on Osseotite® and Nanotite® for A. actinomycetecomitans, S. mutans and S. sanguis than for P. gingivalis and S. salivarius strains. Nanotite® samples showed the lowest amount of bacterial contamination in comparison to the smoother machined and rougher Osseotite® surfaces.