Influence of Surface Treatment on the Physical Properties and Biofilm Formation of Zirconia- Reinforced Lithium Silicate Ceramics: In Vitro Trial.

PURPOSE: To evaluate the performance of fully crystallized zirconia-reinforced lithium silicate (Celtra Duo, ZLS-CD), partially crystallized zirconia-reinforced lithium silicate (Vita Suprinity, ZLS-VS), and partially sintered lithium disilicate-based (IPS e.max CAD, LD) glass-ceramics submitted to polishing, glazing, or no surface treatment after aging. MATERIAL AND METHODS: Samples of each glass-ceramic material were subjected to polishing with rubber cups (POL), glazing (GL), or no treatment (control: unpolished) and afterward aged with 18,000 thermal cycles (5.C to 55.C). The average roughness, 2D and 3D morphology, contact angle, multispecies biofilm formation (Streptococcus mutans and Candida albicans), and mechanical strength were evaluated with atomic force microscopy (AFM, n = 5), sessile-drop goniometry (n = 5), spectrophotometry (n = 5), and the flexural strength test (n = 10), respectively. Data were analyzed using two-way ANOVA and Tukey test (α = 5%). RESULTS: POL produced lower surface roughness than GL, and ZLS-CD presented higher roughness than LD (P < .05). Surfaces without polishing displayed higher roughness than the POL group (P < .001), greater contact angle (P < .001), and significant morphologic changes, regardless of the glass-ceramic material. Irrespective of the treatment, the contact angle was higher in the ZLS-CD group, and regardless of the material, there was higher biofilm formation and lower flexural strength of the unpolished compared to the POL or GL ceramics. CONCLUSIONS: POL promoted lower roughness and minor morphologic surface alterations, but biofilm formation and flexural strength were similar to the GL group. In general, ZLS-CD and ZLS-VS showed more similar behavior than LD, which makes ZLS glass-ceramic a good option for indirect restorations.

Biosynthesis of silver nanoparticles from Syzygium cumini leaves and their potential effects on odontogenic pathogens and biofilms.

This study analyzed the antimicrobial and antibiofilm action and cytotoxicity of extract (HEScL) and silver nanoparticles (AgNPs-HEScL) from Syzygium cumini leaves. GC-MS, UV-Vis, EDX, FEG/SEM, DLS and zeta potential assays were used to characterize the extract or nanoparticles. Antimicrobial, antibiofilm and cytotoxicity analyses were carried out by in vitro methods: agar diffusion, microdilution and normal oral keratinocytes spontaneously immortalized (NOK-SI) cell culture. MICs of planktonic cells ranged from 31.2-250 (AgNPs-HEScL) to 1,296.8-10,375 µg/ml (HEScL) for Actinomyces naeslundii, Fusobacterium nucleatum, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus mutans, Streptococcus oralis, Veillonella dispar, and Candida albicans. AgNPs-HEScL showed antibiofilm effects (125-8,000 µg/ml) toward Candida albicans, Streptococcus mutans and Streptococcus oralis, and Staphylococcus aureus and Staphylococcus epidermidis. The NOK-SI exhibited no cytotoxicity when treated with 32.8 and 680.3 µg/ml of AgNPs-HEScL and HEScL, respectively, for 5 min. The data suggest potential antimicrobial and antibiofilm action of HEScL, and more specifically, AgNPs-HEScL, involving pathogens of medical and dental interest (dose-, time- and species-dependent). The cytotoxicity of HEScL and AgNPs-HEScL detected in NOK-SI was dose- and time-dependent. This study presents toxicological information about the lyophilized ethanolic extract of S. cumini leaves, including their metallic nanoparticles, and adds scientific values to incipient studies found in the literature.

Amphotericin B, fluconazole, and nystatin as development inhibitors of Candida albicans biofilms on a dental prosthesis reline material: Analytical models in vitro.

STATEMENT OF PROBLEM: The use of antifungals has been suggested during the treatment of denture stomatitis associated with Candida albicans biofilms. However, how time, material surface, and substrates present during adhesion and biofilm development can influence clinical treatment is unclear. PURPOSE: The purpose of this in vitro study was to investigate the growth kinetics of C. albicans biofilms on surfaces of specimens under the influence of adsorbed films and to evaluate the antibiofilm efficacy of antifungal agents: amphotericin B, fluconazole, and nystatin. MATERIAL AND METHODS: Specimens of Silagum-Comfort Soft Relining were submerged in preconditioning systems: phosphate-buffered saline, artificial saliva, fetal bovine serum, and artificial saliva+fetal bovine serum. Planktonic cells were incubated (phosphate-buffered saline+specimens) for 1.5 hours (adhesion phase) and washed with phosphate-buffered saline solution. The specimens were then incubated (YNB+glucose) for 8, 24, and 48 hours (initial, intermediate, and maturation phases). The biofilm sessile minimum inhibitory concentration was determined by the broth microdilution method (7.81 to 500 µg/mL). The metabolic activity of the biofilms was tested by colorimetric assay (cell metabolic activity). Cell viability, relative biomass (µm3), and the thickness of the biofilm (µm) were evaluated by confocal laser scanning microscopy. RESULTS: The highest bioactivity was recorded in the presence of fetal bovine serum. Biofilms treated with fluconazole and amphotericin B were partially inhibited in a dose-dependent manner. Nystatin inhibited metabolic activity mainly from ≥15.63 or 62.5 µg/mL. Variations in magnitude parameters (relative biomass and thickness) were observed depending on the development phases of biofilms, whereas biological parameters (percentage of nonviable cells) were constant throughout the formation of C. albicans biofilms. CONCLUSIONS: The data suggest that partial (fluconazole and amphotericin B) or more effective (nystatin) reduction of metabolic activity of C. albicans biofilms occurred depending on the time and the antifungal and its concentrations.

Candida species biotypes and polyclonality of potentially virulent Candida albicans isolated from oral cavity of patients with orofacial clefts.

OBJECTIVES: This study evaluated the incidence of Candida species, and the genetic diversity and virulence of C. albicans of the oral cavity from patients with cleft lip and palate (CLP). MATERIALS AND METHODS: Oral samples were investigated by microbiological and species-specific PCR methods. The genetic diversity of C. albicans was established using isoenzyme markers, Nei's statistics, and clustering analysis. Hydrolytic enzymes (SAPs and PLs) were analyzed in vitro. RESULTS: Oral colonization by Candida species was observed in 29 patients with CLP (65.9%), and C. albicans was highly prevalent. SAP and PL activities were observed in 100% and 51.9% of isolates, respectively. High genetic diversity and patterns of monoclonal and polyclonal oral colonization by C. albicans were observed among patients with CLP. Two major polymorphic taxa (A and B) and other minor polymorphic taxa (C to J) were identified. Only one of the 16 clusters (taxon A) harbored strains from patients with and without CLP, whereas other clusters harbored strains exclusively from CLP patients. CONCLUSIONS: The anatomical conditions of the oral cavity of patients with CLP contribute to the high incidence of Candida species (C. albicans, C. krusei, C. tropicalis, and/or Candida spp.). Data suggest high genetic diversity of potentially virulent C. albicans strains in the oral cavity of CLP patients. CLINICAL RELEVANCE: Microbiological niches in orofacial clefts can contribute to the emergence of a relative clinical genotypic identity of C. albicans. However, orofacial rehabilitation centers can contribute to the direct and indirect sources of transmission and propagation of Candida species.

Antimicrobial photodynamic therapy mediated by methylene blue coupled to ß-cyclodextrin reduces early colonizing microorganisms from the oral biofilm.

OBJECTIVE: To test the effect of antimicrobial photodynamic therapy (A-PDT) on the oral biofilm formed with early colonizing microorganisms, using the photosensitizer methylene blue coupled with ß-cyclodextrin nanoparticles and red light sources laser or LED (λ =660 nm). METHODS: The groups were divided into (n = 3, in triplicate): C (negative control, 0.9 % NaCl), CX (positive control, 0.2 % chlorhexidine), P (Photosensitizer/Nanoparticle), L (Laser), LED (light-emitting diode), LP (Laser + Photosensitizer/Nanoparticle) and LEDP (LED + Photosensitizer/Nanoparticle). A multispecies biofilm composed ofS. gordonii, S. oralis, S. mitis, and S. sanguinis was grown in microplates containing BHI supplemented with 1% sucrose (w/v) for 24 h. Light irradiations were applied with a laser at 9 J for 90 s (320 J/cm2), or with LED, at 8.1 J for 90 s (8.1 J/cm2). The microbial reduction was assessed by counting viable biofilm microorganisms in selective culture media, before and after the treatments. Data normality was assessed by the Shapiro-Wilk test, and the results were submitted to Kruskal-Wallis analysis, followed by Dunn's test, with a significance level of 5%. RESULTS: The groups LP and LEDP were able to significantly reduce the biofilm microorganism counts by as much as 4 log10 times compared to the negative control group (p < 0.05) and did not statistically differ from the positive control group (CX) (p > 0.05). CONCLUSION: The A-PDT mediated by encapsulated ß-cyclodextrin methylene blue irradiated by Laser or LED was effective in the microbial reduction of multispecies biofilm composed of early colonizing microorganisms.

Antimicrobial effects of silver nanoparticles and extracts of Syzygium cumini flowers and seeds: Periodontal, cariogenic and opportunistic pathogens.

OBJECTIVE: This study aimed to analyze the antimicrobial effects of lyophilized hydroalcoholic extract (HEScSeed and HEScFlower) and silver nanoparticles (AgNPs-HEScSeed and AgNPs-HEScFlower) of S. cumini seed and flower, and to characterize some compounds of these extracts and their NPs. DESIGN: Phytochemical screening was performed by GC-MS. Nanoparticles were characterized by UV-vis spectroscopy, energy-dispersive X-ray (EDX) spectrophotometry, scanning electron microscopy (SEM) and field emission gun (FEG), dynamic light scattering (DLS) and zeta potential (ZP). Antimicrobial susceptibility tests were analyzed by broth microdilution and agar diffusion methods. RESULTS: HEScSeed and HEScFlower showed 7 and 17 phytochemical compounds, respectively. AgNPs-plant extracts were reported as stable and with variable shapes and sizes. All studied species (A. naeslundii, C. albicans, F. nucleatum, S. aureus, S. epidermidis, S. mutans, S. oralis and V. dispar) were susceptible to extracts and AgNPs-plant extracts, with varying degrees of antimicrobial activities (extract: 648.4-5,187.5 µg/mL; AgNPs-plant: 31.2-2,000 µg/mL). CONCLUSION: The extracts of S. cumini seed and flower have antimicrobial action against pathogens of medical and dental interest, whose MIC and MMC are species-dependent. The AgNPs-HEScSeed and AgNPs-HEScFlower have different shapes, sizes, organic compounds, stability and electronegativity (capping), characteristics that contribute to their bacteriostatic and fungistatic effects, but at significantly lower concentrations than plant extracts.

Incidence of Shiga toxin-producing Escherichia coli in diarrheic calves and its susceptibility profile to antimicrobials and Eugenia uniflora L.

The aim of this study was to evaluate the occurrence of Shiga toxin (stx)-producing Escherichia coli (STEC) in diarrheic newborn calves, as well as the resistance profile of this microorganism against antimicrobials routinely used in veterinary therapy. The antimicrobial profile of Eugenia uniflora against E. coli clinical isolates was also analyzed. Specimens from the recto-anal junction mucosa were investigated by using chromogenic medium and identification of E. coli was done using microbiological methods (Gram staining, indole test, methyl red test, Voges-Proskauer test, citrate test, urease test, and hydrogen sulfide test). The stx1 and stx2 genes corresponding to the STEC pathotype were evaluated by using polymerase chain reaction and electrophoresis. The susceptibility profile to antimicrobial agents commonly used in veterinary therapeutic practice and the antimicrobial effect of lyophilized hydroalcoholic extract of E. uniflora L. leaves against E. coli clinical isolates were evaluated by disk diffusion and microdilution methods. Shiga toxin-positive E. coli was identified in 45% of diarrheic newborn calves (stx1 = 23.2%, stx2 = 4.0%, stx1 + stx2 = 18.2%). The frequency of stx-positive E. coli in the bacterial population was equal to 17.0% (168/990 clinical isolates): 97 (9.8%) stx1-positive E. coli, 12 (1.2%) stx2-positive E. coli, and 59 (6.0%) stx1 + stx2-positive E. coli isolates. All stx-positive E. coli analyzed showed resistance to multiple drugs, that is, from 4 to 10 antimicrobials per clinical isolate (streptomycin, tetracycline, cephalothin, ampicillin, sulfamethoxazole + trimethoprim, nitrofurantoin and nalidixic acid, ciprofloxacin, gentamicin, and chloramphenicol). Effective management measures should be implemented, including clinical and laboratory monitoring, in order to promote animal and worker health and welfare, prevent and control the spread of diseases, and ensure effective treatment of infectious diseases. The E. uniflora L. leaves showed inhibition of microbial growth based on the diameter of halos, ranging from 7.9 to 8.0 mm and 9.9 to 10.1 mm for concentrations of 50 and 150 mg/mL, respectively. This plant displayed bacteriostatic action and a minimum inhibitory concentration of 12.5 mg/mL for all clinical isolates. Its clinical or synergistic effects with antimicrobial agents must be determined from clinical and preclinical trials.

Le but de cette étude était d'évaluer la présence d'Escherichia coli (STEC) productrices de Shiga toxine (stx) chez les veaux nouveaunés diarrhéiques, ainsi que le profil de résistance de ce microorganisme aux antimicrobiens couramment utilisés en thérapie vétérinaire. Le profil antimicrobien d'Eugenia uniflora contre les isolats cliniques d'E. coli a également été analysé. Des échantillons de la muqueuse de la jonction recto-anale ont été étudiés en utilisant un milieu chromogène et l'identification d'E. coli a été effectuée à l'aide de méthodes microbiologiques (coloration de Gram, test à l'indole, test au rouge de méthyle, test de Voges-Proskauer, test de citrate, test d'uréase et production de sulfure d'hydrogène). Les gènes stx1 et stx2 correspondant au pathotype STEC ont été évalués en utilisant la réaction en chaîne par polymérase et l'électrophorèse. Le profil de sensibilité aux agents antimicrobiens couramment utilisés dans la pratique thérapeutique vétérinaire et l'effet antimicrobien de l'extrait hydroalcoolique lyophilisé de feuilles d'E. uniflora L. contre les isolats cliniques d'E. coli ont été évalués par des méthodes de diffusion en disque et de microdilution. Des E. coli positifs à la Shiga toxine ont été identifiés chez 45 % des veaux nouveau-nés diarrhéiques (stx1 = 23,2 %, stx2 = 4,0 %, stx1 + stx2 = 18,2 %). La fréquence des E. coli stx-positifs dans la population bactérienne était égale à 17,0 % (168/990 isolats cliniques) : 97 (9,8 %) E. coli positifs pour stx1, 12 (1,2 %) E. coli positifs pour stx2, et 59 isolats d'E. coli positifs pour stx1 + stx2 (6,0 %). Tous les E. coli stx positifs analysés ont montré une résistance à plusieurs médicaments, à savoir de 4 à 10 antimicrobiens par isolat clinique (streptomycine, tétracycline, céphalothine, ampicilline, sulfaméthoxazole + triméthoprime, nitrofurantoïne et acide nalidixique, ciprofloxacine, gentamicine et chloramphénicol). Des mesures de gestion efficaces devraient être mises en oeuvre, y compris une surveillance clinique et de laboratoire, afin de promouvoir la santé et le bien-être des animaux et des travailleurs, de prévenir et de contrôler la propagation des maladies et de garantir un traitement efficace des maladies infectieuses. Les feuilles d'E. uniflora L. ont montré une inhibition de la croissance microbienne basée sur le diamètre des zones, allant de 7,9 à 8,0 mm et de 9,9 à 10,1 mm pour des concentrations de 50 et 150 mg/mL, respectivement. Cette plante a montré une action bactériostatique et une concentration inhibitrice minimale de 12,5 mg/mL pour tous les isolats cliniques. Ses effets cliniques ou synergiques avec les agents antimicrobiens doivent être déterminés à partir d'essais cliniques et précliniques.(Traduit par Docteur Serge Messier).

DNA microsatellite genotyping of potentially pathogenic Candida albicans and C. dubliniensis isolated from the oral cavity and dental prostheses.

This study investigated the incidence, genetic diversity, antifungal sensitivity, and virulence of Candida albicans and C. dubliniensis isolated from subjects using dental prostheses and subjects clinically indicated for the first prosthetic rehabilitation. Subjects were divided into four groups and samples were collected twice: at first rehabilitation by removable partial (A) and total (C) dental prostheses, and replacement of the removable partial (B) and total (D) prostheses. Yeasts were genotyped using DNA microsatellite markers. Microbiological methods were used to screen for azole antifungal resistance and exoenzyme production. In the initial sampling, oral colonization by Candida was observed in 31 (53.4%) subjects in groups A (33.3%), B (68.2%), and D (65%); 20 (47.6%) subjects displayed colonization of prostheses: groups B (50%) and D (45%). The second sampling (±30 days) revealed Candida in 2 (3.4%: oral cavity) and 4 (6.9%: prosthetic) subjects from group B. C. albicans and C. dubliniensis displayed both polyclonal and monoclonal patterns of infection. Azole-resistant C. albicans and SAPs+ strains were prevalent. Related strains were found in one or several oral sites (mucosa and prosthesis), as well as intra- and inter-subject, -gender, -group, and -time of sampling. However, the patterns of clonality can be altered under dental care.

Talinumpaniculatum: a plant with antifungal potential mitigates fluconazole-induced oxidative damage-mediated growth inhibition of Candida albicans / Talinum paniculatum: una planta con potencial antifúngico atenúa la inhibición del crecimiento de Candida albicans mediada por el daño oxidativo inducido por fluconazol

SUMMARY Aims: This study investigated the bioactivity of the crude leaf extract (CLE) and fractions hexane (HX) and ethyl acetate (EtOAc) from Talinum paniculatum alone and in association with fluconazole (FLC) against reference strain and clinical isolates of FLC-resistant Candida albicans. Furthermore, the antioxidant capability, chemical composition of this plant, and the effect's underlying mechanisms were evaluated. Methods: The antifungal activity was evaluated using checkerboard assay to establish the minimum inhibitory (MIC) and minimum microbicidal concen trations (MMC). During FLC and plant products challenges, the reactive oxygen species (ROS) generation (hydroxyl radicals [HO●]) were detected in C. albicans cells using the membrane-permeable fluorescent probes APF and HPF. High-performance liquid chromatography (HPLC) profile, quantitative analysis of antioxidant compounds, and free radical scavenging activity (DPPH assay) tests were performed. Results: The CLE and fractions presented outstanding antifungal activity and selectivity against C. albicans cells but had no synergistic effect's with FLC. The MIC values for CLE and its fractions against C. albicans reference strain were in the order of HX (31.25 µg ml-1) < EtOAc (62.5 μg ml-1) < CLE (500 μg ml-1), and against FLC-resistant C. albicans HX (125 μg ml-1) = EtOAc < CLE (500 μg ml-1). CLE and its fractions had more potent antifungal activities than FLC against the clinical isolates. Moreover, fungicidal effect's for these plant products were demonstrated against FLC-resistant C. albicans, which further conirmed an antifungal potential. Conversely, during association, plant products were shown to cause an increase in FLC MIC anywhere from 2- to 16-fold. FLC exposure led to an increase in the steady-state levels of ROS (HO●) in C. albicans cells. Next, we found that the increases in FLC MICs were owing to action of antioxidants containing-CLE and its fractions in preventing FLC-induced ROS-mediated growth inhibition of C. albicans. Conclusion: T. paniculatum can be a source of bioactive compounds with antifungal potential. However, because of the common use of its edible leaf, caution is advised during therapy with FLC (since it can decrease FLC susceptibility).

RESUMEN Objetivos: este estudio investigó la bioactividad del extracto de hoja en bruto (EHB) y las fracciones hexano (HX) y acetato de etilo (AcOEt) de Talinum paniculatum solo y en asociación con fluconazol (FLC) contra cepas de referencia y aislados clínicos de Candida albicans resistente a FLC. Además, evaluó la capacidad antioxidante, la composición química de esta planta y los mecanismos subyacentes del efecto fungicida. Métodos: la actividad antifúngica se evaluó mediante microdilución en caldo para establecer las concentraciones inhibitorias mínimas (CIM) y microbicidas mínimas (CMM). Durante el tratamiento con FLC y productos vegetales se detectó la generación de especies reactivas de oxígeno (ERO) (radicales hidroxilo [HO●]) en células de C. albicans utilizando las sondas fluorescentes permeables a la membrana APF y HPF. El perfil de cromatografía líquida de alta resolución (CLAR), el análisis cuantitativo de compuestos antioxidantes y el ensayo DPPH fueron evaluados. Resultados: el EHB y las fracciones presentaron una excelente actividad antifúngica y selectividad contra las células de C. albicans, pero no tuvieron efectos sinérgicos con FLC. Los valores de CIM para EHB y sus fracciones contra la cepa referencia de C. albicans fueron del orden de: HX (31,25 μg ml-1) < AcOEt (62,5 μg ml-1) < EHB (500 μg ml-1), y contra C. albicans resistente a FLC: HX (125 μg ml-1)= AcOEt < EHB (500 µg ml-1). EHB y sus fracciones fueron más potentes antifúngicos que FLC contra los aislados clínicos. Además, estos productos vegetales tienen efectos fungicidas contra C. albicans resistentes a FLC, esto conirmó el potencial antifúngico. Por el contrario, durante la asociación se demostró que los productos vegetales causan un aumento en la CIM de FLC de 2 a 16 veces. La exposición a FLC aumentó los niveles de ERO (HO●) en las células de C. albicans. Los aumentos en las CIM de FLC se debieron a la acción de los antioxidantes presentes en EHB y sus fracciones para prevenir la inhibición del crecimiento mediada por ERO inducida por FLC en C. albicans. Conclusión: T. paniculatum puede ser una fuente de compuestos bioactivos con potencial antifúngico. Sin embargo, debido al uso común de su hoja comestible, se recomienda usarla con precaución durante la terapia con FLC (ya que puede disminuir la susceptibilidad a FLC).

Talinum paniculatum leaves with in vitro antimicrobial activity against reference and clinical strains of Staphylococcus aureus interfere with oxacillin action / Las hojas de Talinum paniculatum con actividad antimicrobiana in vitro contra cepas de referencia y clínicas de Staphylococcus aureus interfieren con la acción de la oxacilina

SUMMARY Propose: We evaluated the antibacterial potential of the crude leaf extract (CLE) and fractions hexane (HX) and ethyl acetate (EtOAc) from Talinum paniculatum alone and in association with oxacillin (OXA) against OXA-resistant Staphylococcus aureus (ORSA, environment isolates) and OXA-sensitive S. aureus (OSSA, ATCC 25923). Furthermore, toxicity tests were performed. Methods: The antibacterial activity was evaluated through checkerboard assay (broth microdilution) to establish the minimum inhibitory (MIC) and minimum bactericidal concentrations (MBC). Toxicity test in mice was assessed. Results: The MIC values for the CLE and its fractions against ORSA and OSSA were in the order of HX (500 μg ml-1) = EtOAc < CLE (4000 μg ml-1). EtOAc and HX presented outstanding antibacterial activities against ORSA, and these fractions were bactericidal toward OSSA. Conversely, the associations between plant product (CLE, EtOAc, or HX) and OXA exhibited no synergistic effects. During these associations, there was an increase in OXA MICs anywhere from 2- to 4092-fold. The CLE presented absence of toxicity at a dose of 5 g kg-1 (in vivo). Conclusion: Although T. paniculatum be a good source of bioactive compounds with antistaphylococcal potential, the researchers should be cautious, since its edible leaf may interfere with OXA therapy (mitigating OXA-induced growth inhibition or killing of S. aureus and enhancing S. aureus resistance).

RESUMEN Propósito: evaluamos el potencial antibacteriano del extracto de hoja en bruto (EHB) y las fracciones hexano (HX) y acetato de etilo (AcOEt) de Talinum paniculatum solo y en asociación con oxacilina (OXA) contra Staphylococcus aureus resistente a OXA (ORSA, ambientales) y S. aureus sensible a OXA (OSSA, ATCC 25923). Además, se realizaron pruebas de toxicidad. Métodos: la actividad antibacteriana se evaluó mediante microdilución en caldo para establecer las concentraciones inhibitorias mínimas (CIM) y bactericidas mínimas (CBM). Se evaluó la toxicidad en ratones. Resultados: los valores de CIM para el EHB y sus fracciones contra ORSA y OSSA fueron del orden de HX (500 μg ml-1) = AcOEt < EHB (4000 μg ml-1). AcOEt y HX presentaron actividades antibacterianas sobresalientes contra ORSA, y estas fracciones fueron bactericidas hacia OSSA. Por el contrario, las asociaciones entre el producto vegetal (EHB, AcOEt o HX) y OXA no mostraron efectos sinérgicos. Durante estas asociaciones, hubo un aumento en las CIM de OXA de 2 a 4092 veces. EHB no mostró toxicidad a una dosis de 5 g kg-1. Conclusión: aunque T. paniculatum es una buena fuente de compuestos bioactivos con potencial antiestofilocócico, los investigadores deben ser cautelosos, ya que su hoja comestible puede interferir con la terapia con OXA (mitigando la inhibición del crecimiento inducida por OXA o la muerte de S. aureus y promoviendo resistencia bacteriana).

Antimicrobial potential, phytochemical profile, cytotoxic and genotoxic screening of Sedum praealtum A. DC. (balsam).

BACKGROUND: Sedum praealtum has been used for a long time in traditional medicine as an analgesic and anti-inflammatory agent. Its beneficial effects have been known since ancient times, when Latinos used it to treat sore and swollen eyes. This research evaluated the antimicrobial potential, the cytotoxic and genotoxic effects, and some chromatographic profiles of the hydroethanolic extract of leaves, stems and roots of S. praealtum. METHODS: The antimicrobial activities were carried out by broth microdilution and agar diffusion. In vitro cytotoxicity was evaluated by cell cultures of Aedes albopictus and the selectivity index (SI) was estimated: SI=CI50/MIC. Genotoxic and systemic toxic effects of S. praealtum leaves were analyzed by micronucleus assay in mice bone marrow. Chromatographic profiles and mass spectra were investigated by GC-MS. RESULTS: Gram-positive (B. subtilis, B. cereus, M. luteus, E. faecalis and S. aureus) and gram-negative (E. coli, E. aerogenes, S. marcescens, P. aeruginosa, P. mirabilis and S. typhimurium) bacteria exhibited MICs ranging from 12.5-50 and 0-50 mg/ml, respectively. Sedum praealtum showed no efficacy against M. tuberculosis and M. bovis. Cytotoxicity (CI50) of S. praealtum was 4.22 and 5.96 mg/ml for leaves and stems, respectively, while its roots showed no cytotoxicity. Micronucleated polychromatic erythrocytes (MNPCEs) analyzes showed no differences between treatment doses (0.5-2 g/kg) and negative control (NaCl), but the PCE/NCE ratio (polychromatic erythrocyte/normochromatic erythrocyte) showed significant differences. Phytochemical screening identified thirteen compounds in the leaves, stems and roots of S. praealtum potentially associated with their biological activities. CONCLUSIONS: This research comprises a first scientific study on genotoxicity, cytotoxicity and antimicrobial effects of S. praealtum (Balsam), and it provides an initial theoretical foundation for its comprehensive use. Results showed antibacterial action of S. praealtum against gram-positive bacteria and some gram-negative species (depending on the plant anatomical part), but ineffective antimycobacterial action. However, S. praealtum leaves and stems display potential cytotoxicity, contributing to the SI < 1 values. In addition, S. praealtum leaves exhibit no clastogenic and/or aneugenic effects, but it has systemic toxicity dose-independent.

Isoenzymatic genotyping of Staphylococcus aureus from dairy cattle and human clinical environments reveal evolutionary divergences.

Background The genetic variability of 610 S. aureus isolates from the hands of professional dentists (A), dental clinic environment air (B), bovine milk from cows with and without mastitis (C), an insufflator for milking equipment (D) and milking environment air (E) was studied by isoenzyme genotyping and genetic and cluster analysis. Results Monoclonal and polyclonal patterns of S. aureus were detected in every bacterial population; however, isolates belonging to the same strain were not found among the populations, suggesting the genetic heterogeneity and the intrapopulation spread of strains. Genetic relationship analysis revealed the co-existence of highly related strains at low frequency among populations. Conclusion The data suggest that some strains can adapt and colonize new epidemiologically unrelated habitats. Consequently, the occurrence of an epidemiological genotypic identity can assume a dynamic character (spread to new habitats), however infrequently. A tendency of microevolutionary and genetic divergences among populations of S. aureus from human sources (AB) and bovine milk (DE), and especially the mammary quarter (C), is also suggested. This research can contribute to the knowledge on the distribution and dissemination of strains and the implementation of control measures and eradication of S. aureus in important dental clinic environments, as well as animal environments and dairy production.

Candida species biotypes in the oral cavity of infants and children with orofacial clefts under surgical rehabilitation.

Patients with orofacial clefts present various risk factors for oral infectious diseases, resulting from anatomical and physiological changes and those resulting from rehabilitating therapeutic interventions. The incidence of Candida species in groups of babies and children with orofacial clefts, during pre- and post-operative periods and until return to first consultation, and the profiles for antifungal sensitivity and virulence in vitro were investigated. Oral samples were collected at different times over the surgical procedures and post-surgical clinical consultation and seeded in chromogenic culture media CHROMagar Candida®. Candida biotypes were identified by accessing species-specific genomic DNA sequences by PCR techniques and electrophoretic procedures. Antifungal susceptibility testing was performed by the method of microdilution in broth using the antifungals amphotericin B (AP), nystatin (NYS) and fluconazole (FLC). SAP and PL exoenzyme activities were determined by classical microbiological methods. Some orofacial clefts occurred preferentially in male or female. Low incidence (39.1%) of oral colonization by Candida species (C. albicans, C. krusei, C. tropicalis and Candida spp.) was reported in patient admission to surgical ward, with no correlation to orofacial cleft types or surgical history. Significant reduction in frequencies of Candida and changes of species, over sampling periods, showed dynamic patterns of oral colonization: elimination, maintenance or neocolonization of the biotypes. These biotypes showed sensitivity to AP (100%), partial resistance to FLC (<10%) and variable MICs for NYS (0.125-4 µg/mL), in addition to strong exoenzyme activities, especially for SAP. Clinical and therapeutic conducts for surgical rehabilitation, anatomical and physiological characteristics of patients with orofacial clefts, and cultural behavior and regionalism of the patient population served could influence the frequencies and dynamics of oral colonization by Candida species. The data showed Candida biotypes resistant to FLC and sensitive (AP) or clinically compatible (NYS) to polyenes, especially C. albicans, in the oral cavity of patients predisposed to oral colonization and candidiases, contributing to clinical conducts in possible antifungal therapies. These biotypes were considered potentially virulent and able to partially modulate their virulence factors, especially SAP, under the conditions favored by host.

Dynamics of the seasonal airborne propagation of Staphylococcus aureus in academic dental clinics.

OBJECTIVE: Staphylococcus aureus strains can be disseminated during dental treatments and occasionally lead to the contamination and infection of patients and dentists, which is an important public health problem. The dynamics of the airborne propagation and the genetic diversity of S. aureus isolated in an academic dental clinic environment were investigated using isoenzyme typing. Materials and MethodsThe isoenzymes of 44 previously reported isolates were obtained from fresh cultures and extracted using glass beads. Nine isoenzymes were investigated using multilocus enzyme electrophoresis (MLEE). The genetic diversity and relationship among the strains (electrophoretic type - ET) were determined using statistics previously described by Nei25 (1972) and the SAHN grouping method (UPGMA algorithm). RESULTS: Clonal pattern analyses indicated a high level of genetic polymorphism occurring among the 33 ETs, which were grouped into five taxa. Each taxon presented one or more clusters that were moderately related and that contained two or more identical/highly related isolates, revealing seasonal airborne propagation in these dental clinic environments. CONCLUSIONS: These data suggest the occurrence of active microevolutionary processes in S. aureus as well as the possibility of environmental propagation during a 14-month time span. Such findings are important to show that multiuser academic dental clinics can retain certain strains that are spreadable to different niches.

Dynamics of the seasonal airborne propagation of Staphylococcus aureus in academic dental clinics

Abstract Objective Staphylococcus aureus strains can be disseminated during dental treatments and occasionally lead to the contamination and infection of patients and dentists, which is an important public health problem. The dynamics of the airborne propagation and the genetic diversity of S. aureus isolated in an academic dental clinic environment were investigated using isoenzyme typing. Material and Methods The isoenzymes of 44 previously reported isolates were obtained from fresh cultures and extracted using glass beads. Nine isoenzymes were investigated using multilocus enzyme electrophoresis (MLEE). The genetic diversity and relationship among the strains (electrophoretic type - ET) were determined using statistics previously described by Nei25 (1972) and the SAHN grouping method (UPGMA algorithm). Results Clonal pattern analyses indicated a high level of genetic polymorphism occurring among the 33 ETs, which were grouped into five taxa. Each taxon presented one or more clusters that were moderately related and that contained two or more identical/highly related isolates, revealing seasonal airborne propagation in these dental clinic environments. Conclusions These data suggest the occurrence of active microevolutionary processes in S. aureus as well as the possibility of environmental propagation during a 14-month time span. Such findings are important to show that multiuser academic dental clinics can retain certain strains that are spreadable to different niches.

Isoenzyme genotyping and phylogenetic analysis of oxacillin-resistance Staphylococcus aureus isolates

Aim: The propagation of S. aureus in hospital and dental environments is considered an important public health problem since resistant strains can cause serious infections in humans. The genetic variability of 99 oxacillin-resistant S. aureus isolates (ORSA) from the dental patients (oral cavity) and environments (air) was studied by isoenzyme genotyping. Methods: S. aureus isolates were studied using isoenzyme markers (alcohol dehydrogenase, sorbitol dehydrogenase, mannitol-1-phosphate dehydrogenase, malate dehydrogenase, glucose dehydrogenase, D-galactose dehydrogenase, glucose-6-phosphate dehydrogenase, catalase and α/ß-esterase) and genetic (Nei's statistics) and cluster analysis (UPGMA algorithm). Results: A highly frequent polyclonal pattern was observed in this population of ORSA isolates, suggesting various sources of contamination or microbial dispersion. Genetic relationship analysis showed a high degree of polymorphism between the strains, and it revealed three taxa (A, B and C) distantly genetically related (0.653≤dij≤1.432) and fifteen clusters (I to XV) moderately related (0.282≤dij<0.653). These clusters harbored two or more highly related strains (0≤dij<0.282), and the existence of microevolutionary processes in the population of ORSA. Conclusion: This research reinforces the hypothesis of the existence of several sources of contamination and/or dispersal of ORSA of clinical and epidemiologically importance, which could be associated with carriers (patients) and dental environmental (air) (AU)

Genotypic diversity and phenotypic traits of Streptococcus mutans isolates and their relation to severity of early childhood caries.

BACKGROUND: Early childhood caries (ECC) is an aggressive condition that can affect teeth of young children. This study aimed to evaluate genotypic diversity and phenotypic traits of S. mutans isolated from dental biofilms of children with different caries status in comparison with caries free (CF) children. METHODS: Streptococcus mutans strains were isolated from supragingival biofilm samples of CF, ECC and severe-ECC (S-ECC) children and genotyped by arbitrary-primer polymerase chain reaction - AP-PCR. S. mutans genotypes were tested for their ability to reduce the suspension pH through glycolysis, to tolerate extreme acid challenge and by their ability to form biofilm. Response variables were analyzed by ANOVA/Tukey or Kruskal-Wallis/Mann-Whitney tests at a 5% of significance. RESULTS: There was an increase in the prevalence of Streptococcus mutans in biofilms with the severity of dental caries. No differences in genotypic diversity and in acidogenicity of genotypes were found among CF, ECC and S-ECC children. S mutans strains with genotypes more characteristic for ECC and S-ECC children formed more biofilms than those identified in CF children. The strains isolated from S-ECC children were highly acid tolerant. CONCLUSION: Although S. mutans genotypic diversity was similar among the groups of children, phenotypic traits of S. mutans, especially the acid tolerance response, could explain the severity of early childhood caries.

Genotoxicidade de Helianthus annuus Linné, 1753 (Asteraceae): novas perspectivas e tendências / Genotoxicity of Helianthus annuus Linné, 1753 (Asteraceae): new perspectives and trends

A presente revisão reúne informações acerca dos aspectos genotóxicos de Helianthus annuus Linné (girassol), até o presente momento na literatura. O girassol é uma importante fonte de óleo natural e sua ampla aplicabilidade é atribuível ao variável repertório fitoquímico. A ação preventiva da diurese, diarreia e doenças inflamatórias, além dos efeitos de alívio dos sintomas asmáticos, proteção gástrica, cicatrização, ação anti-inflamatória e antimicrobiana foram reconhecidas quanto às propriedades farmacológicas do girassol. Com um grande potencial fitoquímico, é importante também analisarmos seu potencial tóxico e genotóxico. Vários resultados inconclusivos a respeito da correlação entre a carcinogênese e o óleo de girassol foram observados na literatura. Por outro lado, um número limitado de informações sobre a mutagênese ou antimutagênese do extrato hidroalcoólico e distintas fontes do óleo de sementes de girassol, submetido ou não ao estresse térmico, foi relatado. Esta revisão apresentará os atuais trabalhos envolvendo a ação genotóxica ou anti genotóxica de H. annuus L., colaborando com a implantação de limites ao consumo, potenciais riscos à saúde ou medidas estratégicas quimiopreventivas.(AU)

The present review gathers information about the genotoxic aspects of Helianthus annuus Linné (sunflower), until the present moment in the literature. Sunflower is an important source of natural oil and its wide applicability is attributable to the variable phytochemical repertoire. The preventive action of diuresis, diarrhea and inflammatory diseases, besides the effects of relief of asthmatic symptoms, gastric protection, healing, anti-inflammatory and antimicrobial action were recognized regarding the pharmacological properties of the sunflower. With great phytochemical potential, it is also important to analyze its toxic and genotoxic potential. Several inconclusive results regarding the correlation between carcinogenesis and sunflower oil were observed in the literature. On the other hand, a limited number of information on the mutagenesis or anti-mutagenesis of the hydroalcoholic extract and different sources of sunflower seed oil, whether or not subjected to thermal stress, was reported. This review will present the current works involving the genotoxic or anti genotoxic action of H. annuus L., collaborating with the implementation of consumption limits, potential health risks or strategic chemopreventive measures.(AU)

In vitro mutagenicity assay (Ames test) and phytochemical characterization of seeds oil of Helianthus annuus Linné (sunflower).

The objective of this research was to investigate the genotoxic potential of the oil of H. annuus L. (sunflower) seeds via the Ames test as well as its oxidative properties and lipid composition. The pre-incubation method, system metabolic activation (S9 fraction) and five S. typhimurium strains (TA97, TA98, TA100, TA1535 and TA102) were employed for the Ames test. The oxidative stability and fatty acid composition were analyzed by standard methods and gas chromatography. A revertant analysis showed no significant differences between the treatment doses (10-200 µl/plate) and the negative controls, regardless of S9+ and S9-, and included all of the S. typhimurium strains. Chromatographic analysis showed high levels of polyunsaturated fatty acids, followed by monounsaturated, saturated and total trans-isomers. Among the polyunsaturated, monounsaturated and saturated fatty acids, linoleic, oleic and palmitic acids predominated. The results suggest that the sunflower oil is not genotoxic as indicated by frameshift mutations and base pair substitutions regardless of the treatment dose, but shows dose-dependent toxicity. The oxidative properties of the sunflower oil were consistent with the requirements of national and international standards. However, its composition could also indicate phytotherapeutic properties.