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1.
Stomatologiia (Mosk) ; 99(5): 7-10, 2020.
Artigo em Russo | MEDLINE | ID: mdl-33034170

RESUMO

BACKGROUND: The adhesion ability of microorganisms to the surface of titanium miniplates and screws is one of factors in the development of purulent-inflammatory complications in the postoperative period. One of the solutions to this problem is the use of an ion-plasma coating of mini-plates and screws. OBJECTIVE: The aim of the study was to prove a decrease adhesion level of pathogenic and conditionally pathogenic bacterium to samples of titanium mini-plates with ion-plasma coating, compared with samples without coating. MATERIAL AND METHODS: Present opinion about microbial adhesion, how the most important stage of development microbial colonization of abiotic surfaces, was been basis of this study. The strains of aerobic and facultative anaerobic pathogens, as well as the non-spore-forming (non-clostridial) obligate-anaerobic pathogens were used in the research. During the experiments the standard method for determining residual adhesion was applied. The data obtained were processed by the «Biostat 9.0¼ software package. For the data received by the methods of variational parametric and nonparametric statistics we used the Mann-Whitney test, taking into account the average value, error, and the number of observations (significance of differences at p<0.05). RESULTS: As a result, the differences between the indices residual adhesion of strains aerobic and facultative anaerobic pathogens on the samples with and without a protective coating were statistically reliable, however, the adhesion of the individual species varied. The same differences between the indices residual adhesion were obtained among the strains of obligate anaerobic pathogens. The low level of adhesion, which was observed in the case of using the protective coating, is a very promising way of development, since these microorganisms are dangerous as the may lead to the development of purulent-inflammatory complications and the rejection of implants. CONCLUSION: The decreased level of adhesion is a factor which reduces the microbial load during the postoperative period.


Assuntos
Aderência Bacteriana , Titânio , Ossos Faciais , Propriedades de Superfície
2.
Front Immunol ; 11: 2192, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33072084

RESUMO

During the last years probiotics gained the attention of clinicians for their use in the prevention and treatment of multiple diseases. Probiotics main mechanisms of action include enhanced mucosal barrier function, direct antagonism with pathogens, inhibition of bacterial adherence and invasion capacity in the intestinal epithelium, boosting of the immune system and regulation of the central nervous system. It is accepted that there is a mutual communication between the gut microbiota and the liver, the so-called "microbiota-gut-liver axis" as well as a reciprocal communication between the intestinal microbiota and the central nervous system through the "microbiota-gut-brain axis." Moreover, recently the "gut-lung axis" in bacterial and viral infections is considerably discussed for bacterial and viral infections, as the intestinal microbiota amplifies the alveolar macrophage activity having a protective role in the host defense against pneumonia. The importance of the normal human intestinal microbiota is recognized in the preservation of health. Disease states such as, infections, autoimmune conditions, allergy and other may occur when the intestinal balance is disturbed. Probiotics seem to be a promising approach to prevent and even reduce the symptoms of such clinical states as an adjuvant therapy by preserving the balance of the normal intestinal microbiota and improving the immune system. The present review states globally all different disorders in which probiotics can be given. To date, Stronger data in favor of their clinical use are provided in the prevention of gastrointestinal disorders, antibiotic-associated diarrhea, allergy and respiratory infections. We hereby discuss the role of probiotics in the reduction of the respiratory infection symptoms and we focus on the possibility to use them as an adjuvant to the therapeutic approach of the pandemic COVID-19. Nevertheless, it is accepted by the scientific community that more clinical studies should be undertaken in large samples of diseased populations so that the assessment of their therapeutic potential provide us with strong evidence for their efficacy and safety in clinical use.


Assuntos
Bactérias/imunologia , Betacoronavirus/imunologia , Infecções por Coronavirus , Microbioma Gastrointestinal/imunologia , Pandemias , Pneumonia Viral , Probióticos/uso terapêutico , Aderência Bacteriana/imunologia , Encéfalo/imunologia , Encéfalo/microbiologia , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/microbiologia , Infecções por Coronavirus/terapia , Humanos , Mucosa Intestinal/imunologia , Mucosa Intestinal/microbiologia , Pneumonia Viral/epidemiologia , Pneumonia Viral/imunologia , Pneumonia Viral/microbiologia , Pneumonia Viral/terapia
3.
PLoS One ; 15(9): e0238425, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32960889

RESUMO

OBJECTIVE: To evaluate the effects of Bifidobacterium animalis subsp. lactis HN019 (HN019) on clinical periodontal parameters (plaque accumulation and gingival bleeding), on immunocompetence of gingival tissues [expression of beta-defensin (BD)-3, toll-like receptor 4 (TLR4), cluster of differentiation(CD)-57 and CD-4], and on immunological properties of saliva (IgA levels) in non-surgical periodontal therapy in generalized chronic periodontitis (GCP) patients. Adhesion to buccal epithelial cells (BEC) and the antimicrobial properties of HN019 were also investigated. MATERIALS AND METHODS: Thirty patients were recruited and monitored clinically at baseline (before scaling and root planing-SRP) and after 30 and 90 days. Patients were randomly assigned to Test (SRP+Probiotic, n = 15) or Control (SRP+Placebo, n = 15) group. Probiotic lozenges were used for 30 days. Gingival tissues and saliva were immunologically analyzed. The adhesion of HN019 with or without Porphyromonas gingivalis in BEC and its antimicrobial properties were investigated in in vitro assays. Data were statistically analyzed (p<0.05). RESULTS: Test group presented lower plaque index (30 days) and lower marginal gingival bleeding (90 days) when compared with Control group. Higher BD-3, TLR4 and CD-4 expressions were observed in gingival tissues in Test group than in Control group. HN019 reduced the adhesion of P. gingivalis to BEC and showed antimicrobial potential against periodontopathogens. CONCLUSION: Immunological and antimicrobial properties of B. lactis HN019 make it a potential probiotic to be used in non-surgical periodontal therapy of patients with GCP. CLINICAL RELEVANCE: B. lactis HN019 may be a potential probiotic to improve the effects of non-surgical periodontal therapy. Name of the registry and registration number (ClinicalTrials.gov): "Effects of probiotic therapy in the treatment of periodontitis"-NCT03408548.


Assuntos
Bifidobacterium animalis/imunologia , Periodontite Crônica/terapia , Probióticos/uso terapêutico , Adulto , Aderência Bacteriana/imunologia , Infecções por Bacteroidaceae/imunologia , Infecções por Bacteroidaceae/microbiologia , Infecções por Bacteroidaceae/terapia , Periodontite Crônica/imunologia , Periodontite Crônica/microbiologia , Método Duplo-Cego , Feminino , Interações entre Hospedeiro e Microrganismos/imunologia , Humanos , Imunoglobulina A Secretora/metabolismo , Técnicas In Vitro , Masculino , Pessoa de Meia-Idade , Mucosa Bucal/imunologia , Mucosa Bucal/microbiologia , Porphyromonas gingivalis/patogenicidade , Saliva/imunologia
4.
Nat Commun ; 11(1): 4321, 2020 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-32859904

RESUMO

Bacterial colonization of the human intestine requires firm adhesion of bacteria to insoluble substrates under hydrodynamic flow. Here we report the molecular mechanism behind an ultrastable protein complex responsible for resisting shear forces and adhering bacteria to cellulose fibers in the human gut. Using single-molecule force spectroscopy (SMFS), single-molecule FRET (smFRET), and molecular dynamics (MD) simulations, we resolve two binding modes and three unbinding reaction pathways of a mechanically ultrastable R. champanellensis (Rc) Dockerin:Cohesin (Doc:Coh) complex. The complex assembles in two discrete binding modes with significantly different mechanical properties, with one breaking at ~500 pN and the other at ~200 pN at loading rates from 1-100 nN s-1. A neighboring X-module domain allosterically regulates the binding interaction and inhibits one of the low-force pathways at high loading rates, giving rise to a catch bonding mechanism that manifests under force ramp protocols. Multi-state Monte Carlo simulations show strong agreement with experimental results, validating the proposed kinetic scheme. These results explain mechanistically how gut microbes regulate cell adhesion strength at high shear stress through intricate molecular mechanisms including dual-binding modes, mechanical allostery and catch bonds.


Assuntos
Aderência Bacteriana/fisiologia , Microbioma Gastrointestinal/fisiologia , Fenômenos Mecânicos , Fenômenos Físicos , Bactérias , Aderência Bacteriana/genética , Proteínas de Ciclo Celular , Proteínas Cromossômicas não Histona , Trato Gastrointestinal/microbiologia , Técnicas de Inativação de Genes , Humanos , Cinética , Simulação de Dinâmica Molecular , Método de Monte Carlo , Ligação Proteica , Conformação Proteica , Imagem Individual de Molécula , Estresse Mecânico
5.
Int J Nanomedicine ; 15: 5473-5489, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32801701

RESUMO

Introduction: Biofilms protect bacteria from antibiotics and this can produce drug-resistant strains, especially the main pathogen of periodontitis, Porphyromonas gingivalis. Carbon quantum dots with various biomedical properties are considered to have great application potential in antibacterial and anti-biofilm treatment. Methods: Tinidazole carbon quantum dots (TCDs) and metronidazole carbon quantum dots (MCDs) were prepared by a hydrothermal method with the clinical antibacterial drugs tinidazole and metronidazole, respectively. Then, TCDs and MCDs were characterized by transmission electron microscopy, UV-visible spectroscopy, infrared spectroscopy and energy-dispersive spectrometry. The antibacterial effects were also investigated under different conditions. Results: The TCDs and MCDs had uniform sizes. The results of UV-visible and energy-dispersive spectrometry confirmed their important carbon polymerization structures and the activity of the nitro group, which had an evident inhibitory effect on P. gingivalis, but almost no effect on other bacteria, including Escherichia coli, Staphylococcus aureus and Prevotella nigrescens. Importantly, the TCDs could penetrate the biofilms to further effectively inhibit the growth of P. gingivalis under the biofilms. Furthermore, it was found that the antibacterial effect of TCDs lies in its ability to impair toxicity by inhibiting the major virulence factors and related genes involved in the biofilm formation of P. gingivalis, thus affecting the self-assembly of biofilm-related proteins. Conclusion: The findings demonstrate a promising new method for improving the efficiency of periodontitis treatment by penetrating the P. gingivalis biofilm with preparations of nano-level antibacterial drugs.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Porphyromonas gingivalis/efeitos dos fármacos , Pontos Quânticos/química , Animais , Antibacterianos/efeitos adversos , Aderência Bacteriana/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Carbono/química , Carbono/farmacologia , Escherichia coli/efeitos dos fármacos , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Humanos , Metronidazol/química , Metronidazol/farmacologia , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Transmissão , Periodontite/microbiologia , Porphyromonas gingivalis/genética , Porphyromonas gingivalis/fisiologia , Coelhos , Espectrofotometria Ultravioleta , Staphylococcus aureus/efeitos dos fármacos , Tinidazol/química , Tinidazol/farmacologia , Fatores de Virulência/antagonistas & inibidores
6.
Rev. Odontol. Araçatuba (Impr.) ; 41(2): 52-57, maio-ago.2020. tab, ilus
Artigo em Português | LILACS, BBO - Odontologia | ID: biblio-1102702

RESUMO

Objetivo: avaliar a adesão bacteriana do Streptococcus mutans na superfície de uma resina composta do tipo incremento único submetida a diferentes protocolos de polimento. Materiais e métodos: foram realizadas 60 amostras nas quais foram divididas aleatoriamente em 6 grupos (n=10) de diferentes tratamentos de superfície. Cinco amostras de cada grupo foram separadas e submetidas ao estudo de adesão bacteriana, das quais duas foram analisadas pela microscopia eletrônica de varredura. Foram contabilizadas as unidades formadoras de colônias UFC/ml de modo manual e realizada a média e desvio padrão de cada grupo. De acordo com os resultados analisados através do teste de One Way ANOVA e comparações múltiplas de Tukey observou-se uma diferença estatisticamente significativa entre os grupos. Resultados: os valores de UFC/ mL variaram de 0 para o grupo American Burrs a 8,64 para o grupo Dhpro. Os grupos Jota e Dhpro não diferiram estatisticamente entre si (p=0,71), porém diferiram dos demais grupos avaliados (p=0,45). Os grupos American Burrs e o controle negativo não diferiram estatisticamente entre si (p>0.999) e diferiram dos demais grupos testados (p=0,20). O grupo de controle positivo diferiu estatisticamente dos outros grupos (p=0,02) assim como o grupo KG (p=0,01). Conclusão: Diante dos resultados obtidos, pode-se concluir que, a superfície da resina Bulk Fill One submetida a diferentes protocolos de polimento e mesmo sem ter passado por nenhum tratamento de superfície é passível de adesão bacteriana seja por contagem manual ou microscopia eletrônica de varredura(AU)


Objective: To evaluate the bacterial adhesion of Streptococcus mutans on the surface of a single increment composite resin submitted to different polishing protocols. Materials and methods: 60 samples were randomly divided into 6 groups (n = 10) of different surface treatments. Five samples from each group were separated and submitted to the bacterial adhesion study, two of which were analyzed by scanning electron microscopy. The UFC/ml colony forming units were accounted for manually and the mean and standard deviation of each group were performed. According to the results analyzed by the One Way ANOVA test and Tukey's multiple comparisons, a statistically significant difference was observed between the groups. Results: The values ranged from 0 for the American Burrs group to 8.64 for the Dhpro group. The Jota and Dhpro groups did not differ statistically (p = 0.71), but differed from the other groups evaluated (p = 0.45). The American Burrs and negative control groups did not differ statistically (p> 0.999) and differed from the other groups tested (p = 0.20). The positive control group differed statistically from the other groups (p = 0.02) as did the KG group (p = 0.01). Conclusion: It can be concluded that the surface of the Bulk Fill One resin submitted to different polishing protocols and even without any surface treatment is susceptible to bacterial adhesion either by manual counting or scanning electron microscopy(AU)


Assuntos
Streptococcus mutans , Aderência Bacteriana , Resinas Compostas , Resinas Sintéticas , Microscopia Eletrônica de Varredura
7.
Int J Oral Maxillofac Implants ; 35(4): 773-781, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32724931

RESUMO

PURPOSE: Surface treatments may significantly affect physical-chemical properties and surface biologic responses. This study aimed to investigate the influence of alterations in the physical-chemical properties of pure titanium with different surface topographies on biocompatibility and early microbiologic response. MATERIALS AND METHODS: Titanium disks were exposed to five different surface treatments created through acid etching and anodizing methods. Surface morphology, 2D and 3D roughness, wettability, biocompatibility, and cell viability were evaluated. Osteoblast adhesion and bacterial adhesion tests were also executed. Data were statistically analyzed using analysis of variance followed by Tukey test, roughness (P < .05), and bacterial proliferation (P < .05). RESULTS: Five different surface morphologies were developed; double acid etching was shown to be significantly rougher than the others. The 2D roughness measurements were shown to be less consistent than the 3D measurements. All surfaces presented biocompatibility to allow cell behavior and differentiation. Osteoblasts presented better evolution in terms of adhesion and behavior in the nanomorphologies. High roughness significantly increased bacterial adhesion. CONCLUSION: Surface treatments may critically alter titanium properties and morphology. Therefore, roughness measurements with a wide area should be used in their evaluation. Nanotextured surfaces show a positive effect on bone cells and antibacterial response; their application is suggested when considering surface texturization for biomedical implants.


Assuntos
Implantes Dentários , Titânio , Aderência Bacteriana , Adesão Celular , Proliferação de Células , Osteoblastos , Propriedades de Superfície
8.
PLoS One ; 15(7): e0227395, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32628681

RESUMO

The FluidFM enables the immobilization of single cells on a hollow cantilever using relative underpressure. In this study, we systematically optimize versatile measurement parameters (setpoint, z-speed, z-length, pause time, and relative underpressure) to improve the quality of force-distance curves recorded with a FluidFM. Using single bacterial cells (here the gram negative seawater bacterium Paracoccus seriniphilus and the gram positive bacterium Lactococcus lactis), we show that Single Cell Force Spectroscopy experiments with the FluidFM lead to comparable results to a conventional Single Cell Force Spectroscopy approach using polydopamine for chemical fixation of a bacterial cell on a tipless cantilever. Even for the bacterium Lactococcus lactis, which is difficult to immobilze chemically (like seen in an earlier study), immobilization and the measurement of force-distance curves are possible by using the FluidFM technology.


Assuntos
Aderência Bacteriana , Lactococcus lactis/fisiologia , Microscopia de Força Atômica/métodos , Paracoccus/fisiologia , Células Imobilizadas/fisiologia , Vidro/química , Indóis/química , Polímeros/química , Água do Mar/microbiologia , Análise de Célula Única , Propriedades de Superfície , Titânio/química
9.
J Infect Public Health ; 13(10): 1397-1404, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32712106

RESUMO

Secondary bacterial infections are commonly associated with prior or concomitant respiratory viral infections. Viral infections damage respiratory airways and simultaneously defects both innate and acquired immune response that provides a favorable environment for bacterial growth, adherence, and facilitates invasion into healthy sites of the respiratory tract. Understanding the molecular mechanism of viral-induced secondary bacterial infections will provide us a chance to develop novel and effective therapeutic approaches for disease prevention. The present study describes details about the secondary bacterial infection during viral infections and their immunological changes.The outcome of discussion avails an opportunity to understand possible secondary bacterial infections associated with novel SARS-CoV-2, presently causing pandemic outbreak COVID-19.


Assuntos
Infecções Bacterianas/imunologia , Infecções Bacterianas/virologia , Infecções por Coronavirus/imunologia , Influenza Humana/imunologia , Pneumonia Viral/imunologia , Imunidade Adaptativa , Bactérias/crescimento & desenvolvimento , Aderência Bacteriana , Betacoronavirus , Infecções por Coronavirus/complicações , Humanos , Tolerância Imunológica , Imunidade Inata , Inflamação/complicações , Influenza Humana/complicações , Interações Microbianas , Pandemias , Gravidade do Paciente , Pneumonia Viral/complicações
10.
Nat Commun ; 11(1): 3545, 2020 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-32669564

RESUMO

Group A Streptococcus (GAS) infection causes a range of diseases, but vaccine development is hampered by the high number of serotypes. Here, using reverse vaccinology the authors identify SPy_2191 as a cross-protective vaccine candidate. From 18 initially identified surface proteins, only SPy_2191 is conserved, surface-exposed and inhibits both GAS adhesion and invasion. SPy_2191 immunization in mice generates bactericidal antibodies resulting in opsonophagocytic killing of prevalent and invasive GAS serotypes of different geographical regions, including M1 and M49 (India), M3.1 (Israel), M1 (UK) and M1 (USA). Resident splenocytes show higher interferon-γ and tumor necrosis factor-α secretion upon antigen re-stimulation, suggesting activation of cell-mediated immunity. SPy_2191 immunization significantly reduces streptococcal load in the organs and confers ~76-92% protection upon challenge with invasive GAS serotypes. Further, it significantly suppresses GAS pharyngeal colonization in mice mucosal infection model. Our findings suggest that SPy_2191 can act as a universal vaccine candidate against GAS infections.


Assuntos
Proteínas de Bactérias/imunologia , Proteção Cruzada/imunologia , Infecções Estreptocócicas/prevenção & controle , Vacinas Estreptocócicas/imunologia , Streptococcus pyogenes/imunologia , Animais , Aderência Bacteriana/imunologia , Linhagem Celular , Clonagem Molecular , Modelos Animais de Doenças , Feminino , Humanos , Imunogenicidade da Vacina , Camundongos , Testes de Neutralização , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/imunologia , Sorogrupo , Infecções Estreptocócicas/microbiologia , Vacinas Estreptocócicas/administração & dosagem , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/imunologia
11.
Proc Natl Acad Sci U S A ; 117(29): 17249-17259, 2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32641516

RESUMO

Control of infections caused by carbapenem-resistant Klebsiella pneumoniae continues to be challenging. The success of this pathogen is favored by its ability to acquire antimicrobial resistance and to spread and persist in both the environment and in humans. The emergence of clinically important clones, such as sequence types 11, 15, 101, and 258, has been reported worldwide. However, the mechanisms promoting the dissemination of such high-risk clones are unknown. Unraveling the factors that play a role in the pathobiology and epidemicity of K. pneumoniae is therefore important for managing infections. To address this issue, we studied a carbapenem-resistant ST-15 K. pneumoniae isolate (Kp3380) that displayed a remarkable adherent phenotype with abundant pilus-like structures. Genome sequencing enabled us to identify a chaperone-usher pili system (Kpi) in Kp3380. Analysis of a large K. pneumoniae population from 32 European countries showed that the Kpi system is associated with the ST-15 clone. Phylogenetic analysis of the operon revealed that Kpi belongs to the little-characterized γ2-fimbrial clade. We demonstrate that Kpi contributes positively to the ability of K. pneumoniae to form biofilms and adhere to different host tissues. Moreover, the in vivo intestinal colonizing capacity of the Kpi-defective mutant was significantly reduced, as was its ability to infect Galleria mellonella The findings provide information about the pathobiology and epidemicity of Kpi+ K. pneumoniae and indicate that the presence of Kpi may explain the success of the ST-15 clone. Disrupting bacterial adherence to the intestinal surface could potentially target gastrointestinal colonization.


Assuntos
Fímbrias Bacterianas/genética , Klebsiella pneumoniae/genética , Chaperonas Moleculares/genética , Células A549 , Animais , Antibacterianos , Aderência Bacteriana/efeitos dos fármacos , Aderência Bacteriana/genética , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Carbapenêmicos/farmacologia , Linhagem Celular , Modelos Animais de Doenças , Farmacorresistência Bacteriana Múltipla/genética , Células Epiteliais/microbiologia , Europa (Continente) , Feminino , Deleção de Genes , Genes Bacterianos/genética , Humanos , Infecções por Klebsiella , Klebsiella pneumoniae/citologia , Klebsiella pneumoniae/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Tipagem de Sequências Multilocus , Óperon , Filogenia
12.
J Vis Exp ; (159)2020 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-32510489

RESUMO

The opsono-adherence assay is a functional assay that enumerates the attachment of bacterial pathogens to professional phagocytes. Because adherence is requisite to phagocytosis and killing, the assay is an alternative method to opsono-phagocytic killing assays. An advantage of the opsono-adherence assay is the option of using inactivated pathogens and mammalian cell lines, which allows standardization across multiple experiments. The use of an inactivated pathogen in the assay also facilitates work with biosafety level 3 infectious agents and other virulent pathogens. In our work, the opsono-adherence assay was used to assess the functional ability of antibodies, from sera of animals immunized with an anthrax capsule-based vaccine, to induce adherence of fixed Bacillus anthracis to a mouse macrophage cell line, RAW 264.7. Automated fluorescence microscopy was used to capture images of bacilli adhering to macrophages. Increased adherence was correlated with the presence of anti-capsule antibodies in the serum. Non-human primates that exhibited high serum anti-capsule antibody concentrations were protected from anthrax challenge. Thus, the opsono-adherence assay can be used to elucidate the biological functions of antigen specific antibodies in sera, to evaluate the efficacy of vaccine candidates and other therapeutics, and to serve as a possible correlate of immunity.


Assuntos
Vacinas contra Antraz/imunologia , Antraz/imunologia , Anticorpos Antibacterianos/imunologia , Bacillus anthracis/imunologia , Aderência Bacteriana , Proteínas Opsonizantes/imunologia , Animais , Antraz/microbiologia , Antraz/prevenção & controle , Antígenos de Bactérias/imunologia , Fluoresceína-5-Isotiocianato/metabolismo , Fluorescência , Humanos , Macrófagos/imunologia , Camundongos , Primatas/imunologia , Primatas/microbiologia , Células RAW 264.7
13.
PLoS One ; 15(6): e0234524, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32579584

RESUMO

The purpose of this study was to evaluate the adherence of streptococci to disks of titanium (commercially pure titanium: CpTi) and zirconia (tetragonal zirconia polycrystals: TZP). CpTi and yttria-stabilized TZP disks with a mirror-polished surface were used as specimens. The arithmetic mean surface roughness (Ra and Sa) and the surface wettability of the experimental specimens were measured. For analyzing the outermost layer of the experimental specimens, X-ray photoelectron spectroscopy (XPS) analysis was performed. Streptococcus sanguinis, S. gordonii, S. oralis, and S. mutans were used as streptococcal bacterial strains. These bacterial cultures were grown for 24 h on CpTi and TZP. The number of bacterial adhesions was estimated using an ATP-bioluminescent assay, and scanning electron microscope (SEM) observation of the adhered bacterial specimens was performed. No significant differences in surface roughness or wettability were found between CpTi and TZP. In XPS analyses, outermost layer of CpTi included Ti0 and Ti4+, and outermost layer of TZP included Zr4+. In the cell adhesion assay, the adherences of S. sanguinis, S. gordonii, and S. oralis to TZP were significantly lower than those to CpTi (p < 0.05); however, significant difference was not observed for S. mutans among the specimens. The adherence to CpTi and TZP of S. mutans was significantly lower than that of S. sanguinis, S. gordonii, and S. oralis. These results were confirmed by SEM. S. sanguinis, S. gordonii, and S. oralis adhered less to TZP than to CpTi, but the adherence of S. mutans was similar to both surfaces. S. mutans was less adherent compare with the other streptococci tested in those specimens.


Assuntos
Aderência Bacteriana/efeitos dos fármacos , Streptococcus sanguis/efeitos dos fármacos , Titânio/química , Zircônio/química , Teste de Materiais , Microscopia Eletrônica de Varredura , Espectroscopia Fotoeletrônica , Streptococcus sanguis/química , Streptococcus sanguis/ultraestrutura , Propriedades de Superfície/efeitos dos fármacos , Ítrio/química
14.
Nat Commun ; 11(1): 2851, 2020 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-32503979

RESUMO

The colonization of surfaces by bacteria is a widespread phenomenon with consequences on environmental processes and human health. While much is known about the molecular mechanisms of surface colonization, the influence of the physical environment remains poorly understood. Here we show that the colonization of non-planar surfaces by motile bacteria is largely controlled by flow. Using microfluidic experiments with Pseudomonas aeruginosa and Escherichia coli, we demonstrate that the velocity gradients created by a curved surface drive preferential attachment to specific regions of the collecting surface, namely the leeward side of cylinders and immediately downstream of apexes on corrugated surfaces, in stark contrast to where nonmotile cells attach. Attachment location and rate depend on the local hydrodynamics and, as revealed by a mathematical model benchmarked on the observations, on cell morphology and swimming traits. These results highlight the importance of flow on the magnitude and location of bacterial colonization of surfaces.


Assuntos
Aderência Bacteriana , Biofilmes/crescimento & desenvolvimento , Escherichia coli/fisiologia , Modelos Biológicos , Pseudomonas aeruginosa/fisiologia , Fenômenos Biomecânicos , Hidrodinâmica , Técnicas Analíticas Microfluídicas , Movimento/fisiologia , Propriedades de Superfície
15.
PLoS One ; 15(6): e0234306, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32555615

RESUMO

Moraxella catarrhalis is a human-adapted, opportunistic bacterial pathogen of the respiratory mucosa. Although asymptomatic colonization of the nasopharynx is common, M. catarrhalis can ascend into the middle ear, where it is a prevalent causative agent of otitis media in children, or enter the lower respiratory tract, where it is associated with acute exacerbations of chronic obstructive pulmonary disease in adults. Phase variation is the high frequency, random, reversible switching of gene expression that allows bacteria to adapt to different host microenvironments and evade host defences, and is most commonly mediated by simple DNA sequence repeats. Bioinformatic analysis of five closed M. catarrhalis genomes identified 17 unique simple DNA sequence repeat tracts that were variable between strains, indicating the potential to mediate phase variable expression of the associated genes. Assays designed to assess simple sequence repeat variation under conditions mimicking host infection demonstrated that phase variation of uspA1 (ubiquitous surface protein A1) from high to low expression occurs over 72 hours of biofilm passage, while phase variation of uspA2 (ubiquitous surface protein A2) to high expression variants occurs during repeated exposure to human serum, as measured by mRNA levels. We also identify and confirm the variable expression of two novel phase variable genes encoding a Type III DNA methyltransferase (modO), and a conserved hypothetical permease (MC25239_RS00020). These data reveal the repertoire of phase variable genes mediated by simple sequence repeats in M. catarrhalis and demonstrate that modulation of expression under conditions mimicking human infection is attributed to changes in simple sequence repeat length.


Assuntos
Regulação Bacteriana da Expressão Gênica/genética , Moraxella catarrhalis/genética , Aderência Bacteriana/genética , Proteínas da Membrana Bacteriana Externa/genética , Proteínas da Membrana Bacteriana Externa/metabolismo , Expressão Gênica/genética , Humanos , Repetições de Microssatélites/genética , Moraxella catarrhalis/patogenicidade , Infecções por Moraxellaceae , Otite Média/microbiologia , Sequências Repetitivas de Ácido Nucleico/genética
16.
Nat Commun ; 11(1): 2877, 2020 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-32513917

RESUMO

Mycoplasma genitalium is a human pathogen adhering to host target epithelial cells and causing urethritis, cervicitis and pelvic inflammatory disease. Essential for infectivity is a transmembrane adhesion complex called Nap comprising proteins P110 and P140. Here we report the crystal structure of P140 both alone and in complex with the N-terminal domain of P110. By cryo-electron microscopy (cryo-EM) and tomography (cryo-ET) we find closed and open Nap conformations, determined at 9.8 and 15 Å, respectively. Both crystal structures and the cryo-EM structure are found in a closed conformation, where the sialic acid binding site in P110 is occluded. By contrast, the cryo-ET structure shows an open conformation, where the binding site is accessible. Structural information, in combination with functional studies, suggests a mechanism for attachment and release of M. genitalium to and from the host cell receptor, in which Nap conformations alternate to sustain motility and guarantee infectivity.


Assuntos
Aderência Bacteriana , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Mycoplasma genitalium/metabolismo , Proteínas de Bactérias/ultraestrutura , Sítios de Ligação , Cristalografia por Raios X , Humanos , Mutação/genética , Domínios Proteicos , Multimerização Proteica , Estrutura Secundária de Proteína , Relação Estrutura-Atividade
17.
Arch Microbiol ; 202(8): 2071-2081, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32488560

RESUMO

Streptococcus intermedius is a causative agent of brain or liver abscesses. S. intermedius produces intermedilysin that plays a pivotal role in pathogenicity. We identified other pathogenic factors and described a fibronectin binding protein (FBP) homolog of S. intermedius (FbpI) that mediated bacterial adhesion to epithelial cells and virulence for mice. The amino acid sequence of FbpI is similar to that of atypical FBPs, which do not possess a conventional secretion signal and an anchoring motif. A full-length recombinant FbpI (rFbpI) bound to immobilized fibronectin in a dose-dependent manner. The fibronectin binding activity of an N-terminal construct of rFbpI comprising the translation initiation methionine of the open reading frame to lysine 265 (rFbpI-N) bound immobilized fibronectin to a much lesser extent compared with rFbpI. A construct comprising the C-terminal domain (alanine 266 to methionine 549; rFbpI-C) bound immobilized fibronectin equivalently to rFbpI. Adherence of the isogenic mutant ΔfbpI to cultured epithelial cells and immobilized fibronectin was significantly lower than that of the wild-type strain. Abscess formation of ΔfbpI reduced in a mouse infection model compared with that in the wild-type. Thus, FbpI may play a role in bacterial adhesion to host cells and represent a critical pathogenic factor of S. intermedius.


Assuntos
Infecções Estreptocócicas/microbiologia , Infecções Estreptocócicas/patologia , Streptococcus intermedius/genética , Streptococcus intermedius/patogenicidade , Virulência/genética , Animais , Aderência Bacteriana , Bacteriocinas , Proteínas de Transporte/metabolismo , Modelos Animais de Doenças , Fibronectinas/metabolismo , Humanos , Camundongos , Ligação Proteica , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Streptococcus intermedius/metabolismo
18.
Arch Microbiol ; 202(8): 2117-2125, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32506149

RESUMO

Plastics composed of polyethylene are non-biodegradable and are mostly harmful to the environment. Literature studies documented that the extent of microbial degradation of low-density polyethylene (LDPE) seems to be insufficient and the underlying mechanisms of such degradation remain unexplored. In the present study, efforts were given to degrade LDPE by a recently isolated bacteria Enterobacter cloacae AKS7. Scanning electron microscopic (SEM) image, tensile strength, and weight loss analysis confirmed the efficient degradation of LDPE by AKS7. To investigate the mechanism, it was observed that with the progression of time, the extent of microbial colonization got increased considerably over the LDPE surface. It was also observed that the organism (AKS7) gradually increased the secretion of extracellular polymeric substances (EPS) suggesting the formation of efficient biofilm over the LDPE surface. Furthermore, to comprehend the role of cell-surface hydrophobicity towards biofilm formation, two mutants of AKS7 were screened that showed a considerable reduction in cell-surface hydrophobicity in contrast to its wild type. The result showed that the mutants revealed compromised LDPE degradation than wild-type cells of AKS7. Further investigation revealed that the mutant cells of AKS7 were incapable of adhering to LDPE in contrast to wild-type cells. Thus, the results demonstrated that the cell-surface hydrophobicity of AKS7 favors the development of microbial biofilm over LDPE that leads to the enhanced degradation of LDPE by AKS7. Therefore, the organism holds the assurance to be considered as a promising bio-remediating agent for the sustainable degradation of polythene-based hazardous waste.


Assuntos
Enterobacter cloacae/genética , Enterobacter cloacae/metabolismo , Recuperação e Remediação Ambiental , Polietileno/metabolismo , Aderência Bacteriana/genética , Biodegradação Ambiental , Biofilmes , Genes Bacterianos/genética , Interações Hidrofóbicas e Hidrofílicas , Microscopia Eletrônica de Varredura , Mutação
19.
Nat Commun ; 11(1): 2803, 2020 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-32499566

RESUMO

Host-associated reservoirs account for the majority of recurrent and oftentimes recalcitrant infections. Previous studies established that uropathogenic E. coli - the primary cause of urinary tract infections (UTIs) - can adhere to vaginal epithelial cells preceding UTI. Here, we demonstrate that diverse urinary E. coli isolates not only adhere to, but also invade vaginal cells. Intracellular colonization of the vaginal epithelium is detected in acute and chronic murine UTI models indicating the ability of E. coli to reside in the vagina following UTI. Conversely, in a vaginal colonization model, E. coli are detected inside vaginal cells and the urinary tract, indicating that vaginal colonization can seed the bladder. More critically, bacteria are identified inside vaginal cells from clinical samples from women with a history of recurrent UTI. These findings suggest that E. coli can establish a vaginal intracellular reservoir, where it may reside safely from extracellular stressors prior to causing an ascending infection.


Assuntos
Células Epiteliais/microbiologia , Escherichia coli Uropatogênica/patogenicidade , Vagina/microbiologia , Animais , Aderência Bacteriana , Infecções por Escherichia coli/microbiologia , Feminino , Camundongos , Camundongos Endogâmicos C3H , Microscopia de Fluorescência , Fagocitose , Bexiga Urinária/microbiologia , Sistema Urinário/microbiologia , Infecções Urinárias/microbiologia , Vagina/citologia
20.
Prog Orthod ; 21(1): 14, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32476070

RESUMO

BACKGROUND: Because changes in surface properties affect bacterial adhesion, orthodontic bonding procedures may significantly influence biofilm formation and composition around orthodontic appliances. However, most studies used a mono-species biofilm model under static conditions, which does not simulate the intraoral environment and complex interactions of oral microflora because the oral cavity is a diverse and changeable environment. In this study, a multi-species biofilm model was used under dynamic culture conditions to assess the effects of the orthodontic bonding procedure on biofilm formation and compositional changes in two main oral pathogens, Streptococcus mutans and Porphyromonas gingivalis. METHODS: Four specimens were prepared with bovine incisors and bonding adhesive: untreated enamel surface (BI), enamel surface etched with 37% phosphoric acid (ET), primed enamel surface after etching (PR), and adhesive surface (AD). Surface roughness (SR), surface wettability (SW), and surface texture were evaluated. A multi-species biofilm was developed on each surface and adhesion amounts of Streptococcus mutans, Porphyromonas gingivalis, and total bacteria were analyzed at day 1 and day 4 using real-time polymerase chain reaction. After determining the differences in biofilm formation, SR, and SW between the four surfaces, relationships between bacteria levels and surface properties were analyzed. RESULTS: The order of SR was AD < PR < BI < ET, as BI and ET showed more irregular surface texture than PR and AD. For SW, ET had the greatest value followed by PR, BI, and AD. S. mutans and P. gingivalis showed greater adhesion to BI and ET with rougher and more wettable surfaces than to AD with smoother and less wettable surfaces. The adhesion of total bacteria and S. mutans significantly increased over time, but the amount of P. gingivalis decreased. The adhesion amounts of all bacteria were positively correlated with SR and SW, irrespective of incubation time. CONCLUSIONS: Within the limitations of this study, changes in SR and SW associated with orthodontic bonding had significant effects on biofilm formation and composition of S. mutans and P. gingivalis.


Assuntos
Biofilmes , Streptococcus mutans , Animais , Aderência Bacteriana , Bovinos , Porphyromonas gingivalis , Propriedades de Superfície
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