Clonal profile, virulence and resistance of Staphylococcus aureus isolated from sheep milk

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação das características de superfície e formação de biofilmes em materiais odontológicos tratados em plasmas de HMDSO

Pós-graduação em Reabilitação Oral - FOAR

Identificação de bactérias do filoplano de citros capazes de interromper o quórum sensing em Xanthomonas citri subsp. citri

Pós-graduação em Microbiologia Agropecuária - FCAV

Green tea extract and its major constituent epigallocatechin-3-gallate inhibit growth and halitosis-related properties of Solobacterium moorei

Background: Solobacterium moorei is a volatile sulfide compound (VSC)-producing Gram-positive anaerobic bacterium that has been associated with halitosis. The aim of this study was to investigate the effects of green tea extract and its major constituent epigallocatechin-3-gallate (EGCG) on growth and severalhalitosis-related properties of S. moorei.Methods: A microplate dilution assay was used to determine the antibacterial activity of green tea extract and EGCG against S. moorei. Their effects on bacterial cell membrane integrity were investigated by transmission electron microscopy and a fluorescence-based permeability assay. Biofilm formation was quantified by crystal violet staining. Adhesion of FITC-labeled S. moorei to oral epithelial cells was monitored by fluorometry. The modulation of beta-galactosidase gene expression in S. moorei was evaluated by quantitative RT-PCR.Results: The green tea extract as well as EGCG inhibited the growth of S. moorei, with MIC values of 500 and 250 mu g/ml, respectively. Transmission electron microscopy analysis and a permeabilization assay brought evidence that the bacterial cell membrane was the target of green tea polyphenols. Regarding the effects of green tea polyphenols on the S. moorei colonization properties, it was found that biofilm formation on EGCG-treated surfaces was significantly affected, and that green tea extract and EGCG can cause the eradication of pre-formed S. moorei biofilms. Moreover, both the green tea extract and EGCG were found to reduce the adherence of S. moorei to oral epithelial cells. The beta-galactosidase activity of S. moorei, which plays a key role in VSC production, was dose-dependently inhibited by green tea polyphenols. In addition, EGCG at 1/2 MIC significantly decreased the beta-galactosidase gene expression.Conclusion: Our study brought evidence to support that green tea polyphenols possess a number of properties that may contribute to reduce S. moorei-related halitosis. Therefore, these natural compounds may be of interest to be used to supplement oral healthcare products.

Effects of Ciprofloxacin-containing Scaffolds on Enterococcus faecalis Biofilms

Introduction: Antibiotic-containing polymer-based nanofibers (hereafter referred to as scaffolds) have demonstrated great potential for their use in regenerative endodontics from both an antimicrobial and cytocompatibility perspective. This study sought to evaluate in vitro the effects of ciprofloxacin (CIP)-containing polymer scaffolds against Enterococcus faecalis biofilms. Methods: Human mandibular incisors were longitudinally sectioned to prepare radicular dentin specimens. Sterile dentin specimens were distributed in 24-well plates and inoculated with E. faecalisfor biofilm formation. Infected dentin specimens were exposed to 3 groups of scaffolds, namely polydioxanone (PDS) (control), PDS + 5 wt% CIP, and PDS + 25 wt% CIP for 2 days. Colony-forming units (CFU/mL) (n = 10) and scanning electron microscopy (SEM) (n -= 2) were performed to quantitatively and qualitatively assess the antimicrobial effectiveness, respectively. Results: PDS scaffold containing CIP at 25 wt% showed maximum bacteria elimination with no microbial growth, differing statistically (P < .05) from the control (PDS) and from PDS scaffold containing CIP at 5 wt%. Statistical differences (P < .05) were also seen for the CFU/mL data between pure PDS (5.92-6.02 log CFU/mL) and the PDS scaffold containing CIP at 5 wt% (5.39 5.87 log CFU/mL). SEM images revealed a greater concentration of bacteria on the middle third of the dentin specimen. after 5 days of biofilm formation. On scaffold exposures, SEM images showed similar results when compared with the CFU/mL data. Dentin specimens exposed to PDS + 25 wt% CIP scaffolds displayed a practically bacteria-free surface. Conclusions: On the basis of the data presented, newly developed antibiotic-containing electrospun scaffolds hold promise as an intracanal medicament to eliminate biofilm/infection before regenerative procedures.

Risk factors for infection with coagulase-negative staphylococci in newborns from the neonatal unit of a brazilian university hospital

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Antimicrobial activity of a tissue conditioner combined with a biocide polymer

The characteristics of tissue conditioners support microorganism development that can threaten the health of the dentures user. The object of this study was to evaluate the effect on antimicrobial activity, roughness and wettability surface of a tissue conditioners material combined with the antimicrobial polymer poly (2-tert-butilaminoethyl) methacrylate (PTBAEMA). Specimens of tissue conditioner (Coe Soft(®)) were divided into three groups, according to the concentration of PTBAEMA incorporated (0, 10 and 25%). Antimicrobial activity was assessed by adherence assay of one of the microorganisms, Staphylococcus aureus, Streptococcus mutans and Candida albicans. Roughness measurements were made using a Mitutoyo SJ-400, and the mean arithmetic roughness values (Ra) obtained were used for the comparisons. The wettability properties were determined by contact angle measurements. The group containing 25% of PTBAEMA inhibited totally the S. aureus and S. mutans biofilm formation. A significant reduc tion in the S. aureus (Kruskal-Wallis, p = 0,001) and S. mutans (Kruscal-Wallis, p = 0,001) count for 10% PTBAEMA group compared with respective control group. No significant difference was found for C. albicans among PTBAEMA groups and control group (ANOVA, p > 0,05). Incorporating 10 and 25% PTBAEMA increased surface roughness and decreased contact angles (ANOVA and Tukey's post hoc tests, α = 5%). Incorporating 10% PTBAEMA into tissue conditioner increases wettability and roughness of tissue conditioner surface; and decreases the adhesion of S. mutans and S. aureus on material surface, but did not exhibit antimicrobial effect against C. albicans. The PTBAEMA incorporated into tissue conditioner could prevent biofilm formation on elderly patient.

Utilização de bacteriófagos ambientais no controle de biofilmes de Salmonella spp. em superfícies utilizadas na indústria de processamento e comercialização de frango de corte e derivados

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeito de scaffolds de nanofibras incorporados com antibióticos sobre biofilmes formados por bactérias presentes nos canais radiculares

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Genetic evaluation and activity of antifungal against clinical isolate Candida albicans biofilms

Candida yeasts are common in the oral cavity and can cause candidosis in the presence of predisposing factors, especially diabetes. The manifestation of the disease is related to this set of local factors such as the presence of dental prostheses, salivary pH, salivary flow and tobacco and the ability to form biofilms. Biofilms are specific and organized communities of cells under the control of signaling molecules rather than random accumulations of cells resulting from cell division and frequently are drugs resistance. Aim: The objectives of this study were to determine the genetic patterns of these C. albicans isolates and to evaluate the in vitro activity amphotericin B and caspofungin against C. albicans biofilms. Methods: Microbial samples were collected from subgingival sites and seeded in CHROMagar for subsequent identification of C. albicans by PCR. Genotypes were defined based on the identification of the transposable introns in the 25S rDNA by PCR. Results: In this study, 6 strains were identified as C. albicans and of these, 3 strains were genotype A and 3 were genotype B. The results showed that both amphotericin B and caspofungin exhibited strong antifungal activities against C. albicans biofilm formation and inhibiting the biofilm formation ranging from 70.8 – 95.3% and 77.7 - 88.7%, respectively. The antifungals studied had low inhibitory effect on preformed biofims, ranging from 39.5 - 50.8% for amphotericin B and from 23.1 - 36.9% for caspofungin at the same concentration. The activity of the two drugs was most effective in inhibit biofilm formation.

Prospecção de substâncias anti histoplasma capsulatum nas formas planctônica e biofilme e análise proteômica

Pós-graduação em Biociências e Biotecnologia Aplicadas à Farmácia - FCFAR

Efeito do tirosol sobre biofilmes de Streptococcus mutans

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Características genotípicas de Staphylococcus coagulase-negativos e taxas de cura da mastite ovina

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Papel de cepas de Streptococcus mutans e Bifidobacterium spp. na etiologia ou proteção contra doenças bucais

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudo de genes de Candida albicans com função desconhecida quanto à formação de biofilme, características biológicas e interação patógeno- hospedeiro

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)