Quercetin, widely distributed in fruits and vegetables, is a flavonoid known for its antioxidant, antiviral, antimicrobial, and antiinflammatory properties. Several studies highlight the potential use of quercetin as an antiviral, due to its ability to inhibit the initial stages of virus infection, to be able to interact with proteases important for viral replication, and to reduce inflammation caused by infection. Quercetin could also be useful in combination with other drugs to potentially enhance the effects or synergistically interact with them, in order to reduce their side effects and related toxicity. Since there is no comprehensive compilation about antiviral activities of quercetin and derivates, the aim of this review is providing a summary of their antiviral activities on a set of human viral infections along with mechanisms of action. Thus, the following family of viruses are examined: Flaviviridae, Herpesviridae, Orthomyxoviridae, Coronaviridae, Hepadnaviridae, Retroviridae, Picornaviridae, Pneumoviridae, and Filoviridae.

The purpose of this study was to explore the microbiological and periodontal changes occurring in adolescents during 12 months of orthodontic therapy with removable aligners and with fixed appliances. During the years 2012–2013, 50 teenagers aged 10–18 years with similar initial orthodontic conditions participated in this trial in a university clinic in northern Italy. After receiving professional oral hygiene and instructions on a standardized oral hygiene protocol, the adolescents were randomly assigned to either orthodontic treatment with traditional fixed brackets (n = 25) or to treatment with Invisalign® aligners (n = 25). Subgingival microbiological samples, probing depth (PD), plaque index (PI), and bleeding on probing (BOP) were obtained and documented from the mesiovestibular subgingival sulcus of the upper right first molar and left central incisor at the beginning of treatment and 3, 6, and 12 months later. Compliance with oral hygiene procedures, full mouth plaque score (FMPS), and full mouth bleeding score (FMBS) were assessed at the beginning of treatment and 12 months later. Two sample independent t-tests and the χ² test were used to study whether the indices of periodontal health differed in the teenagers due to the experimental conditions. None of the patients was positive for the periodontal anaerobes analyzed. The PI, PD, BOP, FMPS, and FMBS scores were significantly lower and compliance with oral hygiene was significantly higher in the group treated with Invisalign® than in the group treated with fixed brackets. Teenagers treated with removable appliances display better compliance with oral hygiene, less plaque, and fewer gingival inflammatory reactions than their peers with fixed appliances. Gegenstand dieser Untersuchung waren die mikrobiologischen und parodontalen Veränderungen bei Jugendlichen über 12 Behandlungsmonate mit herausnehmbaren Alignern oder festsitzenden Apparaturen. Die Studie umfasst 50 Teenager (10–18 Jahre) mit vergleichbaren kieferorthopädischen Indikationen, behandelt in den Jahren 2012 und 2013 an einer norditalienischen Universitätsklinik. Nach einer professionellen Hygienesitzung und Unterweisung in einem standardisierten Mundhygieneverfahren erfolgte nach dem Zufallsprinzip die Zuordnung der Jugendlichen zu einer von 2 Behandlungsgruppen mit traditionellen Klebebrackets (n = 25) oder Invisalign®-Schienen (n = 25). Zu Behandlungsbeginn sowie 3, 6 und 12 Monate danach erfolgten mikrobiologische Probenentnahmen im Oberkiefer aus dem mesiovestibulären Sulkusbereich des rechten ersten Molaren und linken mittleren Schneidezahns sowie eine Beurteilung auf Sondiertiefen, Plaqueindex und provozierte Blutungen. Außerdem beurteilten wir zu Behandlungsbeginn und 12 Monate danach die Hygienedisziplin sowie die Gesamtindizes FMPS (Full Mouth Plaque Score) und FMBS (Full Mouth Bleeding Score). Zweistichproben-t-Tests für unabhängige Stichproben und der χ²-Test dienten dem Auffinden von Gruppenunterschieden bei den parodontalen Indizes. Tests auf 4 anaerobe Parodontalkeime waren für alle Patienten negativ. Die Invisalign®-Gruppe zeigte gegenüber der Bracket-Gruppe signifikant niedrigere Werte für Plaqueindex, Sondiertiefen, provozierte Blutungen sowie FMPS- und FMBS-Werte. Auch die Hygienedisziplin war in der Invisalign®-Gruppe signifikant besser. Im Vergleich zu Gleichaltrigen mit festsitzenden Apparaturen zeigten die mit herausnehmbaren Aligners behandelten Teenager eine bessere Hygienedisziplin sowie weniger Plaque und Entzündungsreaktionen.

Streptococcus suis is a major bacterial pathogen of young pigs causing worldwide economic problems for the pig industry. S. suis is also an emerging pathogen of humans. Colonization of porcine oropharynx by S. suis is considered to be a high risk factor for invasive disease. In the oropharyngeal cavity, where glucose is rapidly absorbed but dietary α-glucans persist, there is a profound effect of carbohydrate availability on the expression of virulence genes. Nineteen predicted or confirmed S. suis virulence genes that promote adhesion to and invasion of epithelial cells were expressed at higher levels when S. suis was supplied with the α-glucan starch/pullulan compared to glucose as the single carbon source. Additionally the production of suilysin, a toxin that damages epithelial cells, was increased more than ten-fold when glucose levels were low and S. suis was growing on pullulan. Based on biochemical, bioinformatics and in vitro and in vivo gene expression studies, we developed a biological model that postulates the effect of carbon catabolite repression on expression of virulence genes in the mucosa, organs and blood. This research increases our understanding of S. suis virulence mechanisms and has important implications for the design of future control strategies including the development of anti-infective strategies by modulating animal feed composition.

Health-care systems that develop rapidly and efficiently may increase the lifespan of humans. Nevertheless, the older population is more fragile, and is at an increased risk of disease development. A concurrently growing number of surgeries and transplantations have caused antibiotics to be used much more frequently, and for much longer periods of time, which in turn increases microbial resistance. In 1945, Fleming warned against the abuse of antibiotics in his Nobel lecture: “The time may come when penicillin can be bought by anyone in the shops. Then there is the danger that the ignorant man may easily underdose himself and by exposing his microbes to non-lethal quantities of the drug make them resistant”. After 70 years, we are witnessing the fulfilment of Fleming’s prophecy, as more than 700,000 people die each year due to drug-resistant diseases. Naturally occurring antimicrobial peptides protect all living matter against bacteria, and now different peptidomimetic strategies to engineer innovative antibiotics are being developed to defend humans against bacterial infections.