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Dahle, Ulf R & Petersen, Fernanda Cristina
(2023).
Antimicrobial resistance:
A challenge that crosses borders.
Vis sammendrag
https://www.uio.no/om/aktuelt/universitetsplassen/domus-bibliotheca/arrangementer/2023/resisforce-norse-program-db-english.pdf
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Petersen, Fernanda Cristina; Soni, Nancy; Rued, Britta; Sribasgaran, Biramitha & Ghafoor, Saba
(2023).
Resisforce: an international partnership bringing together research and education on biofilm and antimicrobial resistance.
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Petersen, Fernanda Cristina
(2023).
Experiences from the FutureLearn Online Course Exploring the Landscape of Antibiotic Resistance in Microbiomes.
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McLaughlin, Kendra J.; Junges, Roger; Levine, Alissa; Petersen, Fernanda Cristina & Nicolau, Belinda Farias
(2023).
Exploring Dental Professionals' Attitudes Toward Antimicrobial Resistance and Their Role in Mitigating Health Risks.
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Smith, Clay; Nicolau, Belinda Farias; Junges, Roger; Petersen, Fernanda Cristina & Levine, Alissa
(2023).
Perceptions, Attitudes, Beliefs, and Recommendations Regarding Antimicrobial Resistance and Antibiotic Prescriptions: A Qualitative Study Among McGill DMD Students.
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Dhariwal, Achal; Petersen, Fernanda Cristina; Chen, Tsute & Baker, Jonathon
(2023).
Introduction to Resistome: key concepts and hands-on analysis.
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Petersen, Fernanda Cristina
(2022).
Antimicrobial resistance: challenges and prospects
Closing remarks.
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Petersen, Fernanda Cristina
(2022).
Antimicrobial resistance: challenges and prospects
Opening remarks.
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Petersen, Fernanda Cristina
(2022).
Collateral effects of antibiotics on the human microbiome: does it matter?
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Ghafoor, Saba; Salvadori, Gabriela; Ricomini-Filho, Antônio Pedro; Marques, Dalton; Petersen, Fernanda Cristina & Nicolau, Belinda Farias
[Vis alle 8 forfattere av denne artikkelen]
(2022).
Dental education on antibiotic resistance: a qualitative analysis of the educators’ perspectives.
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Brar, Navdeep Kaur; Dhariwal, Achal; Junges, Roger; Håkansson, Anders & Petersen, Fernanda Cristina
(2022).
Potential of HAMLET, a human milk protein-lipid complex, to modulate ecological changes in the oral microbiome induced by amoxicillin.
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Ghafoor, Saba; Salvadori, Gabriela; Ricomini-Filho, Antônio Pedro; Marques, Dalton; Petersen, Fernanda Cristina & Nicolau, Belinda Farias
[Vis alle 8 forfattere av denne artikkelen]
(2022).
Dental education on antibiotic resistance.
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Rajar, Polona; Dhariwal, Achal; Salvadori, Gabriela ; Junges, Roger; Åmdal, Heidi Aarø & Berild, Dag
[Vis alle 12 forfattere av denne artikkelen]
(2022).
Microbial DNA extraction of high-host content and low biomass samples: optimized protocol for nasopharynx metagenomic studies.
Vis sammendrag
Low microbial biomass and high human DNA content in nasopharyngeal aspirate samples hinder comprehensive characterization of microbiota and resistome. We obtained samples from premature infants, a group with increased risk of developing respiratory disorders and infections, and consequently frequent exposure to antibiotics. Our aim was to devise an optimal protocol for handling nasopharyngeal aspirates from premature infants, focusing on host DNA depletion and microbiome and resistome characterization. Three depletion and three DNA extraction protocols were compared, using RT-PCR and whole metagenome sequencing to determine the efficiency of human DNA removal, taxonomic profiling and assignment of antibiotic resistance genes. Protocols were tested using mock communities, as well as pooled and individual patient samples. The only extraction protocol to retrieve the expected DNA yield from mock community samples was based on a lytic method to improve Gram positive recovery (MasterPure™). Only samples depleted with MolYsis™ showed satisfactory, but varied reduction in host DNA content, in both pooled and individual patient samples, allowing for microbiome and resistome characterisation (host DNA content from 15% to 98%). PCR results were indicative of achieved microbial enrichment. Despite high human DNA and low microbial biomass content in nasopharynx aspirates of preterm infants, we were able to reduce host DNA content to levels compatible with downstream shotgun metagenomic analysis, including bacterial species identification and coverage of antibiotic resistance genes. Whole metagenomic sequencing of microbes colonizing the nasopharynx may contribute to explaining the possible role of airway microbiota in respiratory conditions and reveal carriage of antibiotic resistance genes.
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Dhariwal, Achal & Petersen, Fernanda Cristina
(2022).
Using ResistoXplorer for comprehensive visual, statistical, and exploratory analysis of AMR metagenomic data
.
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Dhariwal, Achal & Petersen, Fernanda Cristina
(2022).
ResistoXplorer: a web-based tool for visual, statistical and exploratory data analysis of resistome data.
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Dhariwal, Achal & Petersen, Fernanda Cristina
(2022).
Impact of Long-Term Amoxicillin Treatment on the Gut Microbiome and Resistome.
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Brar, Navdeep Kaur; Dhariwal, Achal; Åmdal, Heidi Aarø; Junges, Roger; Salvadori, Gabriela & Petersen, Fernanda Cristina
(2022).
The Impact of Ampicillin on the Oral Microbiome and Resistome.
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Petersen, Fernanda Cristina
(2022).
Antibiotic exposure: the growing concern about off-target effects.
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Petersen, Fernanda Cristina
(2022).
Off-target impact of antibiotics on the microbiome.
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Brar, Navdeep Kaur; Junges, Roger; Hakansson, Anders P. & Petersen, Fernanda Cristina
(2022).
General IADR conference. The Impact of HAMLET, a Human-Milk Protein Complex, on the Ecology of the Oral Microbiome.
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Ghafoor, Saba; Petersen, Fernanda Cristina & Junges, Roger
(2021).
The global challenge of dental education on antibiotic resistance: a qualitative interview study.
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Dhariwal, Achal & Petersen, Fernanda Cristina
(2021).
Resistoxplorer: A web-based tool for visual, statistical and exploratory analysis of resistome data.
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Shekhar, Sudhanshu; Åmdal, Heidi Aarø & Petersen, Fernanda Cristina
(2021).
Vaccination with the commensal Streptococcus mitis expressing pneumococcal serotype 5 capsule elicits IgG/IgA and Th17 responses against Streptococcus pneumoniae.
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Brar, Navdeep Kaur; Junges, Roger; Hakansson, Anders P. & Petersen, Fernanda Cristina
(2021).
The Impact of HAMLET, a Human-Milk Protein Complex, on the Ecology of the Oral Microbiome.
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Petersen, Fernanda Cristina
(2021).
Let's talk about microbiomes.
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Petersen, Fernanda Cristina
(2021).
Off-target impact of antibiotics.
Vis sammendrag
For almost every drug, there is a trade-off between benefits and risks. For antibiotics, prescription to humans has been largely based on a «better safe than sorry» or «just in case» approach, with little attention paid to risks. In the awake of the antibiotic crisis and the increased focus on a balanced microbiome for health, our attention is now turning to risks, including the unwanted collateral effects on the microbiome. Although antibiotics are used to target specific bacteria in the site of infection, off-target effects are virtually unavoidable. What happens when you take antibiotics is that your microbiome is hit by different antibiotic concentrations. Although these are usually lower than in the targeted infection sites, these concentrations can affect the microbiome, and select for and promote the development of antibiotic resistance. Recent studies driven by advancements in metagenomics are already revealing the impact of antibiotics in enriching for antibiotic resistance among commensals and major pathogens found at off-target sites. As the field moves forward, we expect novel approaches to reduce collateral effects, and an increase in studies providing high quality evidence on the off-target impact of antibiotics.
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Petersen, Fernanda Cristina; Dhariwal, Achal; Bråten, Lars Christian Haugli; Sturød, Kjersti; Junges, Roger & Salvadori, Gabriela
[Vis alle 10 forfattere av denne artikkelen]
(2021).
Off-target impact of long-term amoxicillin treatment.
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Dhariwal, Achal; Petersen, Fernanda Cristina; Junges, Roger & Chen, Tsute
(2020).
ResistoXplorer: a web-based tool for visual, statistical and
exploratory data analysis of resistome data.
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Shekhar, Sudhanshu & Petersen, Fernanda Cristina
(2020).
Neonatal exposure to therapeutic
antibiotic regimens suppresses peripheral and mucosal T cell responses.
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Morais Dornelas Figueira, Louise & Petersen, Fernanda Cristina
(2020).
Cross-Kingdom Impact of Antimicrobial.
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Petersen, Fernanda Cristina
(2020).
Towards epi-omic approaches in the study of microbiomes.
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Rajar, Polona & Petersen, Fernanda Cristina
(2020).
Born in the twilight of antibiotics: Implications of antibiotic use to the preterm infant respiratory microbiome and resistome development
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Petersen, Fernanda Cristina
(2020).
Metagenomic approaches for analysis of AMR in microbiomes.
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Libardi Pagotto, Leonardo; Petersen, Fernanda Cristina & Zwaig Kolstad, Hilde
(2019).
- Har aldri sett så mye snø!
[Internett].
UiO Nettsider.
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Pagotto, LL; Junges, Roger; Salvadori, Gabriela ; Petersen, Fernanda Cristina & Ricomini Filho, AP
(2019).
Inhibition of Streptococcus mutans competence by chlorhexidine gluconate.
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Baker, Jonathon & Petersen, Fernanda Cristina
(2019).
Klebsiella and Providencia emerge as lone survivors following long-term starvation of oral microbiota .
Vis sammendrag
Abstract: It is well-understood that many bacteria have evolved to survive catastrophic events using a variety of mechanisms, which include expression of stress-response genes, quiescence, necrotrophy, and metabolic advantages obtained through mutation. However, the dynamics of individuals leveraging these abilities to gain a competitive advantage in an ecologically complex setting remain unstudied. In this study, we observed the saliva microbiome throughout the ecological perturbation of long-term starvation, allowing only the species best equipped to access and use the limited resources to survive. During the first several days, the community underwent a death phase that resulted in a ∼50–100-fold reduction in the number of viable cells. Interestingly, after this death phase, only three species, Klebsiella pneumoniae, Klebsiella oxytoca, and Providencia alcalifaciens, all members of the family Enterobacteriaceae, appeared to be transcriptionally active and recoverable. Klebsiella are significant human pathogens, frequently resistant to multiple antibiotics, and recently, ectopic colonization of the gut by oral Klebsiella was documented to induce dysbiosis and inflammation. MetaOmics analyses provided several leads for further investigation regarding the ecological success of the Enterobacteriaceae. The isolates accumulated single nucleotide polymorphisms in known growth advantage in stationary phase alleles and produced natural products closely resembling antimicrobial cyclic depsipeptides. The results presented in this study suggest that pathogenic Enterobacteriaceae persist much longer than their more benign neighbors in the salivary microbiome when faced with starvation. This is particularly significant, given that hospital surfaces contaminated with oral fluids, especially sinks and drains, are well-established sources of outbreaks of drug-resistant Enterobacteriaceae.
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Herredsvela Rørvik, Gro & Petersen, Fernanda Cristina
(2019).
C-di-AMP signaling in the oral commensal Streptococcus mitis.
Vis sammendrag
Abstract: Streptococcus mitis (S. mitis) is an oral commensal that normally lives in harmony with the human host and mainly causes disease in immunocompromised individuals. Cyclic di adenosine monophosphate (c-di-AMP) is a second messenger, relaying environmental signals into cellular responses. C-di-AMP is produced by diadenylate cyclases and broken down by phosphodiesterases. It controls a multitude of traits in different bacteria, for example potassium homeostasis, biofilm formation and sensitivity to antibiotics. This signaling system has been studied in several streptococci, but never in S. mitis. In this project, we characterize this signaling system, and investigate any possible effect that changes in the concentration of c-di-AMP has in S. mitis. Knock out mutants of each of the three genes hypothesised to be involved in c-di-AMP turnover (dacA, pde1 and pde2) were made. Effect of possible roles of c-di-AMP in the control of antibiotic susceptibility, survival under stress, growth under different conditions, metabolism and ability to cause disease are investigated in this project.
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Hu, Duoyi & Petersen, Fernanda Cristina
(2019).
Strategies for unveiling upstream regulators controlling Streptococcus pneumoniae quorum-sensing .
Vis sammendrag
Abstract: Drug-resistant Streptococcus pneumoniae (S. pneumoniae) is still listed as a major threat by Centers for Disease Control and Prevention (CDC) despite vaccine usages. Studies have shown that the Rgg/pheromone quorum sensing system is involved in S. pneumoniae pathogenesis. Finding signals or pathways that control the Rgg quorum-sensing provides us hints to design potential treatments. There are at least eight Rgg paralogs in this species, but most of their functions are unclear. We hypothesize that each of those Rgg paralogs controls a distinct gene regulon and behavior. Using a saturation chromosomal mutagenesis strategy combined with a reporter read-out tool, we hope to identify genes or environmental signals that play a role in controlling Rgg quorum-sensing
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Lam, Trinh & Petersen, Fernanda Cristina
(2019).
Droplet Confinement of Streptococcus pneumoniae for Studies of Bacterial Genetic Transformation.
Vis sammendrag
Abstract: Streptococcus pneumoniae (pneumococcus), a deadly bacterial human pathogen, uses genetic transformation to gain antibiotic resistance. Genetic transformation begins when a pneumococcal strain in a transient specialized physiological state called competence, attacks and lyses another strain, releasing DNA, taking up fragments of the liberated DNA, and integrating divergent genes into its genome. While many steps of the process are known and generally understood, the precise mechanism of this natural genetic transformation is not yet fully understood and current standard strategies to study genetic transformation, which usually employ bulk cultures, fail to identify the donor cells or to capture all descendants from a single productive interaction. To overcome these limitations, we have developed a droplet microfluidic system for isolating individual episodes of bacterial transformation between two confined cells of pneumococcus in 10-m diameter droplets, then recovered all descendants of the interacting competent cell (the survivor) and mapped all resulting recombination events (gene replacements) by whole genome sequencing (WGS). By encapsulating the cells in a 10-μm diameter aqueous droplet, we provide an improved experimental model of genetic transformation, as both participating cells can be identified, and the released DNA is spatially restricted near the attacking strain, allowing characterization of natural genetic transformation during a strictly defined interaction between two confined cells.
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Libardi Pagotto, Leonardo & Petersen, Fernanda Cristina
(2019).
Inhibition of Streptococcus mutans competence by chlorhexidine gluconate.
Vis sammendrag
Abstract: Natural competence is a state that allows Streptococcus mutans to genetically transform by capturing DNA from the environment and incorporating it into its genome. The required machinery depends on the expression of the sigX factor sigma, which can be induced by the competence stimulating peptide (CSP) or the sigX inducing peptide (XIP). Chlorhexidine digluconate (CHX) is commonly used as a mouthwash and could interfere with S. mutans sigX expression, making bacteria more or less able to incorporate DNA from the environment, thus contributing to horizontal gene transfer and acquisition. of bacterial resistance. Therefore, the objective of this study was to evaluate the effect of chlorhexidine digluconate (CHX) on competence activation and genetic transformation of S. mutans. S. mutans isogenic mutants containing luciferase reporter were used in the cipB (CSP activation), sigX and comS (XIP activation) gene promoter, with or without deletion of the comS and comC genes. Cultures were prepared and frozen at optical density (OD600) of 0.5. The cultures were diluted (1:10) and distributed into 96-well plates, followed by the addition of 1 mM D-luciferin, 250 nM CSP or 1μM XIP, and increasing CHX concentrations of 0, 0.25, 0.50 or 1.0 µg/mL. The plates were incubated at 37° C for 12 h in a microplate reader, during which growth (OD600) and cipB or sigX (luminescence) expression were measured every 30 min. Luminescence data were normalized by OD600 values and area under the curve (AUC) calculated. The bacterial transformation test was performed using kanamycin resistance amplicon (aRJ02) which was added after 150, 270 or 390 min of growth. After incubation for 1 h, the suspensions were plated on non-selective (TSB) and selective (TSB + kanamycin at 500 µg/mL) agar medium. Data were analyzed by One-way ANOVA and Tukey Test (α = 5%). Chlorhexidine was able to reduce cipB, sigX and comS expression at all concentrations tested and this was also reflected in the decrease of transformation efficiency in all analyzed times. Under the conditions tested, it can be concluded that chlorhexidine digluconate when used at sub-inhibitory concentrations decreases S. mutans ability to capture exogenous DNA and incorporate it into its genome.
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Barbara, E Costa-Oliveira & Petersen, Fernanda Cristina
(2019).
New insights on Intracellular polysaccharides in Streptococcus mutans.
Vis sammendrag
Abstract: The cariogenic biofilm is formed under a dynamic condition of exposing to high carbohydrate concentration (abundance), followed by long periods of nutrients lack (starvation). Under abundance, S. mutans is able to produce acids and also convert the excess of carbohydrates into Intracellular polysaccharides (IPS), a glycogen-like molecule formed by repeated glucose units. Despite unclear, it is believed that IPS could play an important role on energy storage, once S. mutans enzymes can break IPS and generate free glucose for metabolization when extracellular carbohydrate sources deplete. Thus, IPS would contribute on bacterial survival, enhancing bacterial persistence. Additionally, IPS degradation during starvation would be important for keeping acid production, increasing tooth demineralization even when no carbohydrate is available, an important issue that needs more attention. According to RNAseq data, genes responsible to regulate IPS synthesis and degradation are encoded in glg operon and includes glgA (synthase), glgB (branching enzyme), glgC&D (ADP-Glc pyrophosphorylase), and glgP/phsG (phosphorylase). Recent studies have demonstrated that glg operon expression increased under glucose-limiting conditions and downgraded its transcription by the presence of sucrose (Zeng and Burne, 2015). On the other hand, when IPS production was assessed, higher amounts of IPS were formed when cariogenic biofilms were exposed to sucrose (Costa Oliveira et al., 2017). These findings highlight that the mechanisms regulating IPS gene expression and its impact on IPS synthesis and degradation are not well understood. Moreover, the higher amounts of IPS formed in the presence of sucrose and why sucrose was source for increased IPS formation need further investigation. We believe that dissecting the molecular basis for the alterations in these metabolic properties and virulence-related traits (e.g. carbohydrate metabolism, persistence, acid tolerance) will lead to a better understanding of pathogenesis by S. mutans. Also, evaluate IPS metabolism in the presence of sucrose (gene regulation, enzymatic activities, and effects on virulence) would help us to find out if the cariogenicity of sucrose would go beyond extracellular polysaccharide synthesis and acid production.
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Dhariwal, Achal; Junges, Roger & Petersen, Fernanda Cristina
(2019).
Exploratory analysis and Visualization of resistome data.
Vis sammendrag
Abstract: Recently, antimicrobial resistance (AMR) has gained everybody’s attention at a global level due to its impact on public health. Nation-wide surveillance efforts have been going on for characterization of these resistance determinants responsible for AMR. Due to advancements in metagenomics, comprehensive databases have been already established providing hierarchical information such as class, group and mechanism of these antibiotic resistance genes (ARGs). Additionally, some recently developed tools are also able to quantify the abundance of these ARGs present in any metagenomic sample. However, it is still challenging to perform bioinformatics analysis and interpretation of such data. Further, there is no such specific tool developed to support comprehensive downstream analysis and visualization from resistome data. As a result, we are aiming to develop ResistoAnalyst, a user-friendly web-based tool that integrates recent advancements in visualization and statistics techniques, integrated with several comprehensive databases, to enable comprehensive analysis of resistome data generated from metagenomics studies. Development of such tool will enable most clinicians, bench researchers to better understand, and generate hypothesis from their own data in real time. Additionally, ResistoAnalyst will be a valuable resource for sequence-based surveillance and monitoring of antibiotic usage and resistome development.
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Martorano Fernandes, Loyse & Petersen, Fernanda Cristina
(2019).
The role of adhesins of Candida albicans in virulence and pathogenicity of duo-species biofilms with Streptococcus mutans.
Vis sammendrag
Abstract: Denture Stomatitis is a biofilm-dependent disease, in which Candida albicans microorganism is prevalent. The interaction between C. albicans and Streptococcus mutans establishes synergistic relationships that contribute to the development of denture stomatitis. The cellular adhesion of C. albicans and S. mutans is physically mediated by cell wall surface adhesins from both organisms. However, the role of C. albicans adhesins in the interaction with S. mutans and the pathogenic potential of this interaction has not been investigated yet. Therefore, this study aims to evaluate the role of C. albicans cell wall adhesins (ALS1 and ALS3) and hyphal wall protein (HWP1) on the formation of C. albicans and S. mutans duo-species biofilms, and to analyze their virulence in contact with, the in vitro model, of oral epithelium. Duo-species biofilms of C. albicans wild-type SC5314 or C. albicans isogenic mutants (ΔALS1, ΔALS3, and ΔHWP1) along with S. mutans UA159 will be grown on surfaces of poly (methyl) methacrylate (PMMA): G1- C. albicans and S. mutans (control group); G2 - C. albicans ΔALS1 and S. mutans; G3 - C. albicans ΔALS3 and S. mutans; G4 - C. albicans ΔHWP1 and S. mutans. After 48h, the biofilms will be collected for the analysis: colony-forming units (CFU)/mL counting, biofilm dry weight quantification, cell metabolism analysis (XTT), biofilm structural analysis by laser confocal microscopy, and analysis of the interaction between the cells by transmission electron microscopy. For the analysis of the virulence/ pathogenicity of biofilms in tissue invasion, cells of C. albicans and S. mutans will be placed in contact with the in vitro model of oral epithelium. The analysis for the tissue invasion will be a. the detection of lactate dehydrogenase (LDH); b. the release of proinflammatory cytokines; c. histological sections stained with hematoxylin and eosin, d. protein blotting analysis, e. gene expression analysis (PCR), and f. visualization of the biofilm on the tissue by confocal microscopy.
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Morais Dornelas Figueira, Louise & Petersen, Fernanda Cristina
(2019).
Streptococcus mitis regulation and genomic sequencing during interaction with Candida albicans.
Vis sammendrag
Abstract: Candida spp. are commensal and opportunistic fungus that under predisposing conditions can become pathogenic, leading to the clinical manifestation known as candidiasis. Candida albicans is the most prevalent and pathogenic species among oropharyngeal fungal infections. Studies demonstrated that C. albicans interacts with oral bacteria, mainly from the Streptococcus group, and alters the biofilm composition and virulence. Among the Streptococcus species, it was already showed that Streptococcus mitis can modulate C. albicans biofilm development by inhibiting the fungus filamentation and limiting their growth. Also, S. mitis increased virulence factors of C. albicans by upregulating the expression of important pathogenic-associated fungal genes. It is important to highlight that little is known about C. albicans and S. mitis interaction during cocultures. As biological pathways are structured in a complex genetic network of interactions, elucidating these networks can provide valuable information, such as how microorganisms cause disease and interact with each other, or interspecies. In this context, a recent method determined by the transposon mutagenesis technique associated with next generation RNA sequencing (Tn-seq) has been applied to accurately determine quantitative genetic interactions at genomic scale in microorganisms. Using this methodology in cocultures of S. mitis and C. albicans, it is expected to determine regions of the S. mitis and C. albicans genome that are important for their interaction.
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Rued, Britta & Petersen, Fernanda Cristina
(2019).
Quorum sensing regulates expression of a post-translationally modified peptide in Streptococcus mutans.
Vis sammendrag
Abstract: Streptococcus mutans, an etiological agent of dental caries, is an important human pathogen that can cause systemic diseases such as endocarditis. As such, understanding how it regulates virulence factors is of utmost importance. We are investigating a Rgg quorum sensing system in S. mutans that regulates a small biosynthetic operon. This operon produces a small, ribosomally produced and post-translationally modified peptide (RiPP) molecule termed “WGK” for the unusual Trp-Gly-Lys linkage generated by a radical SAM enzyme. The biological implications of WGK production and its regulation by the Rgg system will be discussed.
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Melo Leite Filho, Ademir & Petersen, Fernanda Cristina
(2019).
Cariogenic potential of a duo-species biofilm of Streptococcus mutans and Lactobacillus fermentum exposed to lactose.
Vis sammendrag
Abstract: Prolonged breastfeeding has been associated to an increased risk of children developing dental caries (Moyniha et al., 2019). That association relies on lactose content in human milk, which can be fermented to acids and could provoke tooth demineralization. However, lactose is not rapidly fermented by most lactic acid bacteria (LAB) present in the biofilm as other carbohydrates present in human diet, due to this, the pH cannot fall until it reaches the critical level. Nonetheless L. fermentum can rapidly ferment lactose due to its constitutive production of β-galactosidases which could increase biofilm cariogenicity (Arukha et al. 2015), and studies have shown that Lactobacillus spp. are prevalent in the biofilm of children with severe early childhood caries (S-ECC), being L. fermentum one of the most frequently isolated species (Caufield et al. 2017). Therefore, the aim of this study is to evaluate the cariogenic potential of a duo-species biofilm of Streptococcus mutans and Lactobacillus fermentum when exposed to lactose.
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Campos Vieira, Juliana & Petersen, Fernanda Cristina
(2019).
Cariogenicity of lactose in a Streptococcus mutans biofilm exposed to sucrose.
Vis sammendrag
Abstract: Breastfeeding is recognized for several benefits in health, physical, and mental development of infants (Victora et al., 2016). Despite of breastfeeding benefits, dental caries has been pointed out as the only negative result for infants' health (Tham et al., 2015; Victora et al., 2016). Although breastfeeding has been associated to dental caries, this relationship is not well understood, mainly because that the incidence of dental caries usually occurs with prolonged breastfeeding. Additionally, it occurs especially in children with nocturnal breastfeeding habit (Victora et al., 2016; Peres et al., 2017) that includes fermentable carbohydrates, mainly sucrose, present in the diet. However, lactose present in human milk is considered low cariogenic because it is not rapidly fermented by bacteria when compared sucrose (Rugg-Gunn et al., 1985; Birkhed et al., 1993), which is considered the most cariogenic carbohydrate in the diet. The sucrose is the only substrate for extracellular polysaccharide synthesis (Rölla, 1989; Cury et al., 2000). Thus, the increased risk of caries in children with prolonged breastfeeding could be explained by the interaction of a sucrose source in food, associated with continuous exposure to lactose, in which source could be the breast milk during a night breastfeeding. Therefore, evaluating the association of these carbohydrates is important to understand the main cause of increased dental caries in prolonged breastfeeding.
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Laczkovich, Irina & Petersen, Fernanda Cristina
(2019).
Identification of unannotated pheromone genes by ribosome profiling.
Vis sammendrag
Abstract: S. pneumoniae D39 is an opportunistic pathogen found in the human upper respiratory tract. Through a process known as quorum sensing, D39 regulates natural competence, biofilm formation, and production of antimicrobial peptides. Quorum sensing is enacted through the production of small extracellular signaling peptides which bind directly to membrane-located or cytoplasmic receptors. Examples of the latter receptor type (cytoplasmic) are members of the family of proteins called Rgg. To date, eight Rgg paralogs have been identified in D39 but little is understood about their regulatory activities or the behaviors they control. A considerable barrier to understanding Rgg regulation in S. pneumoniae, or any bacterium containing peptide-dependent quorum sensing system, is the lack of appropriate techniques to identify signaling peptides. Peptide pheromones are encoded by small open reading frames (sORFs) that are typically overlooked in annotations of genomes due to their small size. We have performed Retapamulin-enhanced Ribosome profiling (Ribo-RET) to screen genome-wide translation events to identify sORFs and the subset therein that encode pheromones.
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Petersen, Fernanda Cristina
(2019).
No time to wait: oral research in the twilight of antibiotics.
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Chen, Tsute & Petersen, Fernanda Cristina
(2019).
The Human Oral Microbiome Database: now extended to comprise the aerodigestive tract.
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Baker, Jonathon & Petersen, Fernanda Cristina
(2019).
Exploiting the oral microbiome to prevent tooth decay: has evolution already provided the best tools?
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Federle, Michael & Petersen, Fernanda Cristina
(2019).
Identifying and exploiting bacterial communication networks to manipulate bacterial pathogens.
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Casarin, Renato & Petersen, Fernanda Cristina
(2019).
From colonization to biofilm behavior: a look on severe periodontitis affecting young population.
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Ricomini, Pedro & Petersen, Fernanda Cristina
(2019).
Biofilms: a challenging target.
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Morrison, Donald & Petersen, Fernanda Cristina
(2019).
The oral microbiome: a work in progress .
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Tabchoury, Cinthia; Ricomini, Pedro & Petersen, Fernanda Cristina
(2019).
Welcome to RESISPART symposium.
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Petersen, Fernanda Cristina
(2019).
Symposium and RESISPART partnership: Norway - Brazil - USA.
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Pandey, Sushma; Follin-Arbelet, Benoit; Pun, Chin Babadur; Gautam, Dej K.; Johannessen, Anne C. & Petersen, Fernanda Cristina
[Vis alle 8 forfattere av denne artikkelen]
(2019).
Helicobacter pylori is not present in oral squamous cell carcinomas from cohorts of Norwegian and Nepalese patients .
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Shekhar, Sudhanshu; Khan, Rabia; Schenck, Karl & Petersen, Fernanda Cristina
(2019).
Intranasal immunization with the oral commensal Streptococcus mitis
induces protection against Streptococcus pneumoniae infection.
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Petersen, Fernanda Cristina
(2019).
No time to wait: living in the twilight of antibiotics.
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Junges, Roger; Salvadori, Gabriela; Chen, Tsute & Petersen, Fernanda Cristina
(2019).
Identification of a ComRS-like regulator system in the mitis group of streptococci.
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Pagotto, LL; Junges, Roger; Salvadori, Gabriela ; Petersen, Fernanda Cristina & Ricomoni Filho, Antonio Pedro
(2019).
Inhibition of Streptococcus mutans competence by chlorhexidine gluconate.
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