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1.
J Indian Soc Pedod Prev Dent ; 38(3): 238-246, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33004721

RESUMO

Background: Controlling cariogenic biofilm formation by plant extracts could add to preventive strategies to dental caries. Objective: To evaluate in vitro the role of Aerva Sanguinolenta ethanolic extract on biofilm-induced microbial human enamel demineralization. Methodology: The prepared enamel sections of study group (SG), positive control group (PCG), and negative control group (NCG) were immersed in 2 ml of 0.2% ethanolic extract of A. sanguinolenta, 0.12% chlorhexidine, and distilled water, respectively, for 2 min before subjecting to closed batch culture technique utilizing mono- or dual-species culture media of Streptococcus mutans and Lactobacillus acidophilus. Quantification of biofilm and demineralization of enamel was performed by crystal violet (CV) assay and scanning electron microscope (SEM) attached to energy-dispersive X-ray analysis, respectively. Statistical Analysis: Two-way ANOVA and Tukey's test were used for analysis. Results: CV assay of biofilm recorded the highest and lowest optical absorbance value in NC3 (2.728660) and PC3 (0.364200), respectively. Thus, biofilm formation is highest in NCG and lowest among PCG. Surface roughness and porosity in enamel are greatest among NCG and lowest among SG as evident by SEM. Wt% of calcium (S3 47.7170) and phosphorus ion (S3 22.7330) was highest in SG, closely resembling that of B enamel (Ca = 41.9530, P = 19.6650). Wt% of oxygen is lowest in SG (S3 28.8920) and resembles baseline O2 (37.4950). Thus, the amount of biofilm formation is moderate and amount of demineralization of enamel is least among SGs. Conclusion: Enamel exposed to 2 ml of 0.2% solution of A. sanguinolenta for 2 min could fairly inhibit formation of biofilm and positively inhibit underlying demineralization in cariogenic environment.


Assuntos
Amaranthaceae , Cárie Dentária , Desmineralização do Dente/prevenção & controle , Biofilmes , Esmalte Dentário , Humanos , Extratos Vegetais/farmacologia
2.
Am J Dent ; 33(5): 273-276, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33017531

RESUMO

PURPOSE: To evaluate the effect of glass-ionomer cement (GIC) on gene expression (gtfC, gtfD, covR, and vicR) of Streptococcus mutans (S. mutans) biofilms at 2, 4 and 24 hours. METHODS: Six groups were tested according to the materials and time observation, as follows: ceramic (IPS Empress Esthetic), as the control group, and GIC (Ketac Molar Easymix); and time points of S. mutans biofilm formation (2, 4, and 24 hours). Round-shaped samples (10 x 2 mm) of each material were prepared according to the manufacturers' specifications. GIC discs were handled in a laminar flow hood under aseptic conditions and stored at 100% relative humidity at 37°C for 24 hours to complete setting reaction. The samples were placed in a 24-well plate and immersed in 1.5 ml BHI + 1% sucrose with an inoculum of S. mutans UA159 to allow biofilm growth during 2, 4, and 24 hours. Next, the samples were removed, vortexed and centrifuged to collect cell pellets (n=5) for each material and time point. Pellets were stored at -80°C. Then, RNA was purified using the RNeasy Mini Kit protocol. The RNA was converted in cDNA using iScript cDNA Synthesis according to the manufacturer's recommendations. Analysis of gtfC, gtfD, vicR, and covR expressions was performed using Step One Real-Time qPCR device with specific primers for each gene and the analysis normalized by 16S reference gene expression. Data from gtfC, gtfD, and vicR were analyzed by t-test to compare between groups while Mann-Whitney was used to analyze covR expression (α= 0.05). RESULTS: No significant differences at 2 and 4 hours between materials for all analyzed genes were noted. However, in the 24-hour period, a significant decrease in gtfC and vicR expressions were observed, while covR expression increased when GIC was compared to ceramic. CLINICAL SIGNIFICANCE: The use of glass-ionomer cement decreased the virulence of S. mutans biofilms, which may imply a reduced bacterial cariogenic potential.


Assuntos
Cimentos de Ionômeros de Vidro/farmacologia , Streptococcus mutans/genética , Biofilmes , Sacarose , Virulência
3.
J Contemp Dent Pract ; 21(7): 733-740, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33020355

RESUMO

AIM: Phytomedicine has been commonly practiced as a form of traditional medicine in various cultures for the treatment of oral diseases. Recently, it has gained importance as an alternative to conventional treatment. Several extracts of plants and fruits have been recently evaluated for their potential activity against microorganisms involved in the development of dental caries. The purpose of this study was to evaluate the antimicrobial activity and antiadherent effect of the crude organic extract (COE) and three partitions (aqueous, butanolic, and chloroformic) of Psidium guajava (guava) leaves on a cariogenic biofilm model. MATERIALS AND METHODS: Guava leaves were obtained from the mountains of northern Peru, where they grow wild and free of pesticides. The antimicrobial activity of the COEs and partitions against Streptococcus mutans and Streptococcus gordonii was determined by measuring the inhibition halos, while the effect on biofilm adhesion was determined by measuring the optical density using spectrophotometry. RESULTS: An antibacterial effect of the COE and chloroformic partition against S. gordonii (p < 0.05) was found, as was a significant effect on biofilm adherence, with a minimum inhibitory concentration (MIC) of 0.78 mg/mL, which was maintained throughout the 7 days of evaluation. CONCLUSION: We conclude that the COEs and their chloroformic partition have antimicrobial and antibiotic effects against this strain of S. gordonii, making them of particular interest for evaluation as a promising alternative for the prevention of dental caries. CLINICAL SIGNIFICANCE: By knowing the antimicrobial effect of Psidium guajava, this substance can be effectively used in products aimed to prevent dental caries and periodontal disease.


Assuntos
Anti-Infecciosos/farmacologia , Cárie Dentária/tratamento farmacológico , Psidium , Biofilmes , Humanos , Peru , Folhas de Planta
4.
Wiad Lek ; 73(8): 1761-1764, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33055348

RESUMO

OBJECTIVE: The aim: To investigate current trends in the study of oral biofilm and its control. PATIENTS AND METHODS: Materials and methods: A research of 32 literature sources has been made and it has been taken into account that some terminological differences in determining objects of study. CONCLUSION: Conclusions: Detailed analysis of modern domestic and foreign literature argues the necessity of further in-depth study of oral biofilms. Understanding the ethiological factors and mechanisms of the pathogenesis periodontal tissues inflammatory diseases gives the opportunity to treat targetly by destroying complicated sections of the vital activities and oral biofilm microorganisms relationships.


Assuntos
Doenças Periodontais , Biofilmes , Humanos , Periodonto
5.
Niger J Clin Pract ; 23(9): 1188-1193, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32913155

RESUMO

Aims: The aim of this study was to investigate the antimicrobial effect of Erbium, chromium-doped yttrium, scandium, gallium, and garnet (Er,Cr:YSGG) laser with and without NaOCl solution. A total of 81 extracted human mandibular premolar teeth were used. Materials and Methods: After root canal preparation and sterilization, the samples were inoculated with E. faecalis for 24 hours. The specimens were divided into 4 experimental groups. Group 1 (n = 25) was irradiated with 2 W laser, group 2 (n = 25) was irradiated with 0.75 W laser in combination with 2.5% NaOCl, group 3 (n = 25) was irrigated with 5% NaOCl and group 4 (n = 6) was not treated. Statistical analysis was performed by using Wilcoxon Signed Ranks, Mann-Whitney U and Kruskal-Wallis H tests. Results: The combination of 0.75 W laser with 2.5% NaOCl regime was found to be just as effective at inhibiting the growth of E. faecalis and sterilization of all root canals as 5% NaOCl irrigation (P > 0.001). The 2 W laser had significant bactericidal effect in infected root canals however it did not eradicate all bacteria. The SEM observations were in accordance with the microbiologic findings. Conclusions: Within the limitations of this laboratory study, NaOCl irrigation improved the antimicrobial effect of Er,Cr:YSGG laser irradiation. When the toxic effects of high percentage of NaOCl was considered, the combination of low-powered laser and low concentration of NaOCl can be used as an effective disinfection method in root canal treatment.


Assuntos
Anti-Infecciosos/farmacologia , Biofilmes/efeitos dos fármacos , Cavidade Pulpar/microbiologia , Enterococcus faecalis/efeitos dos fármacos , Lasers de Estado Sólido/uso terapêutico , Irrigantes do Canal Radicular/farmacologia , Hipoclorito de Sódio/farmacologia , Cromo , Érbio , Gálio , Humanos , Preparo de Canal Radicular , Tratamento do Canal Radicular/métodos , Escândio , Ítrio
6.
Braz Dent J ; 31(4): 380-384, 2020 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-32901713

RESUMO

The purpose of this study was to compare biofilm formation on materials used for the fabrication of implant-supported dental prostheses. Twenty discs (D=15 mm, H=3 mm) were fabricated from one of the following restorative materials: yttria tetragonal zirconia polycrystal (Y-TZP); commercially pure titanium (CP-Ti); or heat-cured polymethyl methacrylate (PMMA). Specimens were polished following standard protocols. A non-contact profilometer (NPFLEX, Bruker, UK) was used to assess the surface roughness of each disk; results were reported as Ra (µm). Five strains of Gram-negative bacteria frequently associated with peri-implantitis, Aggregatibacter actinomycetemcomitans, Candida. albicans, Porphyromonas gingivalis, Prevotella intermedia, and Tannerella forsythia, were cultured on hand-polished discs fabricated from heat-cured PMMA, Y-TZP, or CP-Ti to compare biofilm formation on each type of material. The results were reported as colony-forming units per milliliter (CFU/mL). One-way ANOVA and post hoc tests were used to compare surface roughness and bacterial colonization on the respective materials. Statistical significance was set at a = 0.05. Discs fabricated from Y-TZP had a significantly higher Ra value (350 ± 30 µm) than either PMMA, or CP-Ti discs. Discs fabricated from either Y-TZP and CP-Ti may exhibit less colonization by bacteria associated with peri-mucositis and peri-implantitis. Y-TZP and CP-Ti are suggested materials for fabrication of implant-supported prostheses, considering biofilm formation.


Assuntos
Implantes Dentários , Peri-Implantite , Biofilmes , Humanos , Propriedades de Superfície , Titânio
7.
Acta Odontol Latinoam ; 33(2): 104-111, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32920612

RESUMO

Candida dubliniensis (Cd) and Candida albicans (Ca) are the most frequently isolated yeasts in HIV+ patients. Some of the enzymes produced by these yeasts are considered virulence factors since they contribute to pathogenicity of Candida spp. The aim of the present study was to compare production of enzymes such as phospholipase (Ph), proteinase (P), and hemolysin (H) by Cd and Ca strains isolated from periodontal HIV-positive patients receiving and not receiving highly active antiretroviral therapy (HAART). Subgingival biofilm samples were obtained using paper points, and a sample of oral mucosa was taken using a swab. Phenotypic and molecular methods were used to isolate 39 strains of Candida, including 25 strains of Cd and 14 strains of Ca, obtained from 33 periodontal pocket samples and 6 oral mucosa samples collected from 15 HIV+ patients (8 receiving and 7 not receiving HAART). Malt egg-yolk agar, albumin agar and blood agar were used to evaluate pH, P and H production respectively. The strains were inoculated in duplicate and incubated at 37 ºC. Colony and halo diameters were measured. A greater proportion of Ca was observed in patients not receiving HAART, and a higher proportion of Cd was observed in those under HAART, Chi2 p< 0.001. Phospholipase production was observed in 92.9% percent of isolated Ca strains but in none of the isolated Cd strains. Proteinase production was high in Ca and Cd strains isolated from patients not receiving HAART. Hemolysin production was observed in all the studied strains, though it was significantly higher (p=0.04) in Ca and Cd strains isolated from patients not receiving HAART. To sum up, the proportion of Candida dubliniensis strains was highest in the subgingival biofilm of patients receiving HAART, and Cd strains were found to express fewer virulence factors than Ca strains.


Assuntos
Terapia Antirretroviral de Alta Atividade/métodos , Biofilmes/crescimento & desenvolvimento , Candida albicans/enzimologia , Candida albicans/isolamento & purificação , Candida/enzimologia , Candida/isolamento & purificação , Candidíase Bucal/microbiologia , Gengiva/microbiologia , Infecções por HIV/complicações , Candida/classificação , Candida/genética , Candida albicans/genética , Candidíase Bucal/complicações , Genótipo , Infecções por HIV/microbiologia , Humanos , Mucosa Bucal/microbiologia , Fenótipo , Reação em Cadeia da Polimerase , Fatores de Virulência/genética
8.
Int J Oral Maxillofac Implants ; 35(5): 888-899, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32991638

RESUMO

PURPOSE: The aim of this study was to evaluate the formed biofilm on two types of implant surfaces (hydrophilic or hydrophobic) associated with titanium (Ti) or zirconia (Zn) abutments. MATERIALS AND METHODS: Samples were separated into four groups according to type of surface and abutment used (n = 10): (1) hydrophobic/Ti abutment, (2) hydrophilic/Ti abutment, (3) hydrophobic/Zn abutment, and (4) hydrophilic/Zn abutment. Implant-abutment assemblies were incubated with human saliva and supragingival biofilm. Samples of biofilm were evaluated by DNA Checkerboard hybridization, identifying up to 41 species. Scanning electron microscopy (SEM) images were obtained from the implants and abutments. RESULTS: The microbial count was higher for samples from groups with the hydrophilic/Ti abutment, followed by hydrophobic/Zn abutment, hydrophilic/Ti abutment, and hydrophobic/Zn abutment (P < .05). Hydrophilic surfaces and Zn abutments showed the highest counts of microorganisms. Individual bacterial counts were variable between groups; the hydrophilic/Zn abutment group had the highest microbial diversity, including T forsythia, P nigrescens, S oralis, S sanguinis, L casei, M orale, P aeruginosa, P endodontalis, S aureus, S gallolyticus, S mutans, S parasanguinis, S pneumoniae, and C albicans. The hydrophilic/Ti abutment group had the highest count of T forsythia and T denticola, microorganisms of Socransky red complex. The SEM images showed the bacterial colonization in both surfaces of the implant and abutment. CONCLUSION: Different surfaces of implants and abutments showed significant differences in the count and diversity of species. The hydrophilic/Zn abutment group presented the highest count and diversity of target species.


Assuntos
Implantes Dentários , Titânio , Biofilmes , Projeto do Implante Dentário-Pivô , Genômica , Humanos , Teste de Materiais , Zircônio
9.
Artigo em Inglês | MEDLINE | ID: mdl-32925997

RESUMO

This study aimed to determine the prevalence and diversity of archaea and select bacteria in the subgingival biofilm of patients with peri-implantitis in comparison to patients with unaffected implants and patients with periodontitis. Samples of subgingival biofilm from oral sites were collected for DNA extraction (n = 139). A 16S rRNA gene-based polymerase chain reaction assay was used to determine the presence of archaea and select bacteria. Seven samples were selected for direct sequencing. Archaea were detected in 10% of samples from peri-implantitis sites, but not in samples from the unaffected dental implant. Archaea were present in 53% and 64% of samples from mild and moderate/advanced periodontitis sites, respectively. The main representative of the Archaea domain found in biofilm from periodontitis and peri-implantitis sites was Methanobrevibacter oralis. The present results revealed that archaea are present in diseased but not healthy implants. It was also found that archaea were more abundant in periodontitis than in peri-implantitis sites. Hence, the potential role of archaea in peri-implantitis and periodontitis should be taken into consideration.


Assuntos
Implantes Dentários , Peri-Implantite , Periodontite , Archaea , Biofilmes , Humanos , RNA Ribossômico 16S
10.
J Oral Sci ; 62(4): 415-419, 2020 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-32879157

RESUMO

This study sought to evaluate biofilm elimination using the HBW Ultrasonic Ring based on continuous ultrasonic irrigation. Forty-five premolars and molars with complex curvatures were included. An Enterococcus faecalis biofilm was established for 30 days on the extracted teeth. The teeth were then stratified into three experimental groups for instrumentation and irrigation (i.e. HBW Ultrasonic Ring, conventional irrigation, and passive ultrasonic irrigation). Pre- and post-instrumentation samples were collected, and reductions of bacterial load were evaluated by McFarland's scale, counting of colony-forming units, and scanning electronic microscopy. The HBW Ultrasonic Ring promoted a higher reduction in bacterial load relative to conventional irrigation (P < 0.05) and a similar reduction compared with passive ultrasonic irrigation (P > 0.05). These results suggest the HBW Ultrasonic Ring is a promising alternative modality for simultaneous instrumentation and irrigation during root canal treatment, achieving an appropriate level of bacterial reduction and allowing the passage of the irrigating solution throughout the entire working length.


Assuntos
Enterococcus faecalis , Irrigantes do Canal Radicular , Biofilmes , Cavidade Pulpar , Preparo de Canal Radicular , Hipoclorito de Sódio , Irrigação Terapêutica , Ultrassom
11.
Adv Exp Med Biol ; 1267: 81-100, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32894478

RESUMO

Many bacteria are able to actively propel themselves through their complex environment, in search of resources and suitable niches. The source of this propulsion is the Bacterial Flagellar Motor (BFM), a molecular complex embedded in the bacterial membrane which rotates a flagellum. In this chapter we review the known physical mechanisms at work in the motor. The BFM shows a highly dynamic behavior in its power output, its structure, and in the stoichiometry of its components. Changes in speed, rotation direction, constituent protein conformations, and the number of constituent subunits are dynamically controlled in accordance to external chemical and mechanical cues. The mechano-sensitivity of the motor is likely related to the surface-sensing ability of bacteria, relevant in the initial stage of biofilm formation.


Assuntos
Bactérias/metabolismo , Flagelos/metabolismo , Biofilmes , Conformação Proteica , Rotação
12.
Rev. Asoc. Odontol. Argent ; 108(2): 46-51, mayo-ago. 2020. tab
Artigo em Espanhol | LILACS | ID: biblio-1121108

RESUMO

Objetivos: Comparar ex vivo la eficacia del instrumento XP-endo Finisher y del sistema EndoActivator en la reducción/eliminación del biofilm microbiano en conductos radiculares infectados. Materiales y métodos: Se utilizaron 23 premolares inferiores humanos extraídos cuya longitud fue estandarizada en 17 mm. Todos los conductos se prepararon con el sistema WaveOne Gold Medium (#35.06). Los dientes se esterilizaron, se inocularon con Enterococcus faecalis y se separaron en dos grupos experimentales de 10 piezas cada uno. De los 3 dientes remanentes, 1 fue utilizado como control positivo y 2, como controles negativos. En el grupo 1, las soluciones irrigantes se agitaron con XP-endo Finisher. En el grupo 2, se utilizó EndoActivator. Se tomaron muestras antes de la contaminación, luego de esta y después de la agitación de los irrigantes mediante conos de papel estériles. La carga microbiana fue sembrada en agar sangre y los conos se cultivaron en caldo tripteína de soja. La remoción de la carga microbiana se determinó por la presencia o ausencia de turbiedad del medio. Las unidades formadoras de colonias (UFC) remanentes se cuantificaron y los resultados se categorizaron como R1 (≤10 UFC) o R2 (>10 UFC). Los datos fueron analizados mediante la prueba de Fisher. Resultados: No hubo diferencias significativas entre XP-endo Finisher y EndoActivator (P>0,05). El número de usos no influyó sobre la capacidad operativa de ambos instrumentos (AU)


Aim: To compare ex vivo the effectiveness of the XP-endo Finisher and the EndoActivator in biofilm reduction/ removal from infected root canals. Materials and methods: Twenty three extracted human single-rooted lower premolars were selected and standardised to 17 mm in length. All the canals were prepared with WaveOne Gold Medium reciprocating files (#35.06). The teeth were autoclaved and inoculated with Enterococcus faecalis. The infected teeth were then assigned to 2 experimental groups of 10 teeth each according to the final irrigation/agitation protocol. Of the three remaining teeth, one was used as a positive control, and the other two were used as negative controls. In Group 1 the irrigating solutions were agitated with XP-endo Finisher while in Group 2 the EndoActivator was used. All root canals were sampled before and after contamination, and again after irrigant agitation with sterile paper points. The microbial load was spread on blood agar plates and the paper points were cultured in sterile trypticase soy broth. The removal of the microbial load was determined by visual observation of the turbidity of the media and by quantification of the number of colony-forming units (UFC). The results were categorized as R1 (≤10 UFC) or R2 (>10 UFC). Data were analysed by the Fisher's exact test at P<0.05. Results: No significant differences was found between XP-endo Finisher and EndoActivator (P>0.05) regarding their effectiveness in the reduction/removal of the microbial biofilm. The number of uses of both instruments did not affect their operative performance (AU) Conclusion: XPF and EA were both equally effective for microbial biofilm reduction/removal from ex vivo infected root canals (AU)


Assuntos
Irrigantes do Canal Radicular/química , Equipamentos Odontológicos de Alta Rotação , Biofilmes , Instrumentos Odontológicos , Cavidade Pulpar/microbiologia , Técnicas In Vitro , Contagem de Colônia Microbiana/métodos , Eficácia , Análise Estatística , Enterococcus faecalis/isolamento & purificação , Meios de Cultura
13.
J Environ Pathol Toxicol Oncol ; 39(2): 125-136, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32749122

RESUMO

Biofilms are a collective of multiple types of bacteria that develop on a variety of surfaces. Biofilm development results in heightened resistance to antibiotics. Quorum sensing plays an important role in biofilm development as it is one of the common communication mechanisms within cells, which balances and stabilizes the environment, when the amount of bacteria increases. Because of the important implications of the roles biofilms play in infectious diseases, it is crucial to investigate natural antibacterial agents that are able to regulate biofilm formation and development. Various studies have suggested that natural plant products have the potential to suppress bacterial growth and exhibit chemopreventive traits in the modulation of biofilm development. In this review, we discuss and collate potential antibiofilm drugs and biological molecules from natural sources, along with their underlying mechanisms of action. In addition, we also discuss the antibiofilm drugs that are currently under clinical trials and highlight their potential future uses.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Farmacorresistência Bacteriana/efeitos dos fármacos , Infecções/tratamento farmacológico , Extratos Vegetais/farmacologia , Antibacterianos/uso terapêutico , Biofilmes/crescimento & desenvolvimento , Interações Hospedeiro-Patógeno , Humanos , Infecções/microbiologia , Extratos Vegetais/uso terapêutico , Percepção de Quorum/efeitos dos fármacos
14.
Ned Tijdschr Tandheelkd ; 127(7-08): 424-433, 2020.
Artigo em Holandês | MEDLINE | ID: mdl-32840498

RESUMO

The International Caries Consensus Collaboration (ICCC) presented recommendations on terminology, methods of carious tissue removal and managing cavitated carious lesions. It identified 'dental caries' as the disease that dentists should manage by controlling the activity of existing cavitated lesions by preserving as much hard tissue as possible, maintaining pulp sensibility and retaining functional teeth in the long-term. The ICCC recommended the level of hardness as the criterion for determining the clinical consequences of the process of demineralisation and defined new strategies for the selective removal of carious tissue. The starting point is to effectively remove the biofilm from cavitated carious lesions. Only when cavitated carious lesions are either non-cleansable or can no longer be sealed, are restorative interventions indicated, with due regard for the principles of a minimally invasive approach. Applying a restoration facilitates biofilm removal, guards the pulpodental complex and restores form, function and aesthetics.


Assuntos
Cárie Dentária , Biofilmes , Consenso , Dentina , Humanos
15.
Sheng Wu Gong Cheng Xue Bao ; 36(7): 1277-1282, 2020 Jul 25.
Artigo em Chinês | MEDLINE | ID: mdl-32748585

RESUMO

Microbial biofilm, a consortium of microbial cells protected by a self-produced polymer matrix, is considered as one main cause of current bacterial drug resistance. As a new type of antimicrobial agents, antimicrobial peptides provide a new strategy for the treatment of antibiotic resistant bacteria biofilm infections. Antimicrobial peptides have shown unique advantages in preventing microbial colonization of surfaces, killing bacteria in biofilms or disrupting the mature biofilm structure. This review systemically analyzes published data in the recent 30 years to summarize the possible anti-biofilm mechanisms of antimicrobial peptides. We hope that this review can provide reference for the treatment of infectious diseases by pathogenic microbial biofilm.


Assuntos
Peptídeos Catiônicos Antimicrobianos , Bactérias , Biofilmes , Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Bactérias/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Farmacorresistência Bacteriana/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Pesquisa/tendências
17.
J Environ Sci (China) ; 96: 151-162, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32819689

RESUMO

Within the drinking water distribution system (DWDS) using chloramine as disinfectant, nitrification caused by nitrifying bacteria is increasingly becoming a concern as it poses a great challenge for maintaining water quality. To investigate efficient control strategies, operational conditions including hydraulic regimes and disinfectant scenarios were controlled within a flow cell experimental facility. Two test phases were conducted to investigate the effects on the extent of nitrification of three flow rates (Q = 2, 6, and 10 L/min) and four disinfection scenarios (total Cl2=1 mg/L, Cl2/NH3-N=3:1; total Cl2=1 mg/L, Cl2/NH3-N=5:1; total Cl2=5 mg/L, Cl2/NH3-N=3:1; and total Cl2=5 mg/L, Cl2/NH3-N=5:1). Physico-chemical parameters and nitrification indicators were monitored during the tests. The characteristics of biofilm extracellular polymetric substance (EPS) were evaluated after the experiment. The main results from the study indicate that nitrification is affected by hydraulic conditions and the process tends to be severe when the fluid flow transforms from laminar to turbulent (2300

Assuntos
Desinfetantes , Água Potável , Biofilmes , Desinfecção , Nitrificação
18.
Sci Total Environ ; 739: 140166, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32758957

RESUMO

Simulated pharmaceutical wastewater was treated by moving bed biofilm reactor (MBBR) and total reflux sludge reactor process (STR) system. By cultivating specific bacterial groups, optimizing reactor process parameters, and comparatively analyzing the pollutant removal efficiency under stable operating conditions of the system, the treatment efficiency of the two systems under the combined impact load of organic pollutants on the target pollutants indole and naphthalene was studied. The optimal operation parameters of reactors: hydraulic retention time (HRT) was 8 h, aeration was 0.12 m3/h. The effect was better in 25 ± 1 °C than that in 20 ± 2 °C. During stable operation, the average removal rate of chemical oxygen demand (COD) and ammonia nitrogen (NH4+-N) of the MBBR system was significantly higher than that of STR, and the two kinds of target pollutants concentration in water was lower than the detection limit. In the combined impact test of organic pollutants, the dominant bacterial group obtained by domestication had a high degradation ability, so the combined impact of indole and naphthalene had little effect on the two reactors. But in the fourth stage, the residual naphthalene concentration in the STR system effluent exceeded the target value. Therefore, the MBBR process has a stronger treatment effect on pharmaceutical wastewater than the STR system during the stable period and the impact load stage.


Assuntos
Preparações Farmacêuticas , Águas Residuárias , Biofilmes , Reatores Biológicos , Esgotos , Eliminação de Resíduos Líquidos
19.
J Environ Manage ; 274: 111183, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32784083

RESUMO

The use of algal biomass still faces challenges associated with the harvesting stages. To address this issue, we propose an innovative hybrid system, in which a biofilm reactor (BR) operates as an algal biomass production and harvesting unit connected to a high-rate algal pond (HRAP), a wastewater treatment unit. BR did not interfered with the biomass chemical composition (protein = 32%, carbohydrates = 11% and total lipids = 18%), with the wastewater treatment (removals efficiency: chemical oxygen demand = 59%, ammonia nitrogen = 78%, total phosphorus = 16% and Escherichia coli = 1 log unit), and did not alter the sedimentation characteristics of the biomass (sludge volume index = 29 mg/L and humidity content = 92%) in the secondary settling tank of the hybrid system. On the other hand, the results showed that this technology achieved a biomass production about 2.6x greater than the conventional system without a BR, and the efficiency of harvesting of the hybrid system was 61%, against 22% obtained with the conventional system. In addition, the BR promoted an increase in the density (~1011 org/m2) and diversity of microalgae in the hybrid system. Chlorella vulgaris was the most abundant species (>60%) from the 4th week of operation until the end of the experiment. Hence, results confirm that the integration of BR into a wastewater treatment plant optimised the production and harvesting of biomass of the hybrid system, making it a promising technology. The importance of economic and environmental analysis studies of BR is highlighted in order to enable its implementation on a large scale.


Assuntos
Chlorella vulgaris , Microalgas , Biofilmes , Biomassa , Tanques , Eliminação de Resíduos Líquidos , Águas Residuárias
20.
Wiad Lek ; 73(4): 786-788, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32731717

RESUMO

OBJECTIVE: The aim of the present research project was to study the effect of ultrasonic waves on the S. epidermidis ATCC 14990 museum culture. PATIENTS AND METHODS: Materials and methods: A bibliosemantic method - for analyzing previous research based on scientific literature, electronic resources, empirical methods of scientific research (observation, comparison, measurement, experiment) - to study the effect of ultrasound on the strain of S. epidermidis ATCC 14990. RESULTS: Results: A study showed that when exposed to ultrasound for four and a half minutes on a culture of microorganisms S. epidermidis in glass tubes, the number of viable cells in the suspension decreases. CONCLUSION: Conclusions: The influence of ultrasound on the culture of S. epidermidis, studied in the work, showed that the selected and used parameters of ultrasound treatment cause destructive changes in microorganisms. These changes are not fatal for the entire bacterial culture used in the study, but they have a reliable antimicrobial effect.


Assuntos
Staphylococcus epidermidis , Biofilmes , Museus
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