title: [Evaluation of biocidal properties of silver nanoparticles against cariogenic bacteria].
abstract: BACKGROUND
  Antimicrobial properties of silver nanoparticles (SNP's) have been recentl well evaluated, and now are being considered as excellent candidates for therapeutic purposes. It is confirmed, that various solutions of colloidal SNP's possess significant antibacterial properties against such species as: Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa even at low concentrations, although there have been so far only a few researches evaluating antimicrobial activity of SNP's against cariogenic bacteria: Streptococcus mutans, Streptococcus salivarius and Streptococcus mitis responsible for initiation of dental carries. Tooth decay is infectious disease an worldwide, which may occur in patients of every age. Nanotechnology creates a new approach of designing of medical devices preventing or reducing bacterial colonization.
  
  
  METHODS
  Colloidal silver solution (CSS) of concentration 350 ppm was used in this research. Nanoparticles size, shape and solution stability were evaluated. 16 strains of cariogenic bacteria, 4 isolates of each species: S. mutans, S. salivarius, S. sanguinis and S, mitis were obtained from plaque swabs of 7 patients treated for dental carries at Department of Conservative Dentistry, Medical University of Warsaw. MIC and MBC values for CSS's were evaluated.
  
  
  RESULTS
  CSS used in this research is of good stability. No agglomeration or coalescence was observed during 24 hours of experiment. Silver nanoparticles were of round shape and had mean size of 67 nm. MIC values were: 12-25 ppm for S. salivarius, 25 ppm for S. sanguinis, 50-100 ppm for S. mitis and 50 ppm for S. mutans, while MBC values after 1 hour of bacterial contact with nanoparticles were 200-350 ppm for all cariogenic bacterial species. After 24 hours of contact MBC values were: 25-50 ppm for S. salivarius and S. sanguinis, 100-200 ppm for S. mitis and 200 ppmfor S. mutans.
  
  
  CONCLUSIONS
  Antimicrobial properties of CSS depend on nanoparticles concentration and interaction time with bacteria. The susceptibility of cariogenic oral streptococci to silver nanoparticles is diversified. Sufficient concentration which inhibited all cariogenic bacteria in our research was 200 ppm after long (24 hours) period of silver nanoparticles interaction with bacteria.
authors.affiliation: Szpital Kliniczny Dzieciatka Jezus w Warszawie.
authors.forename: Rafal
authors.initials: R
authors.lastname: Pokrowiecki
authors.affiliation: Zaklad Antybiotyków i Mikrobiologii Narodowego Instytutu Leków w Warszawie.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Zareba
authors.affiliation: Zaktad Stomatologii Zachowawczej Instytutu Stomatologii-Warszawskiego Uniwersytetu Medycznego w Warszawie.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Mielczarek
authors.affiliation: Instytut Wysokich Ciśnień, PAN, Laboratorium Nanostruktur Dla Fotoniki i Nanomedycyny w Warszawie.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Opalińska
authors.affiliation: Instytut Wysokich Ciśnień, PAN, Laboratorium Nanostruktur Dla Fotoniki i Nanomedycyny w Warszawie.
authors.forename: Jacek
authors.initials: J
authors.lastname: Wojnarowicz
authors.affiliation: Prywatna Praktyka Lekarska.
authors.forename: Marcin
authors.initials: M
authors.lastname: Majkowski
authors.affiliation: Instytut Wysokich Ciśnień, PAN, Laboratorium Nanostruktur Dla Fotoniki i Nanomedycyny w Warszawie.
authors.forename: Witold
authors.initials: W
authors.lastname: Lojkowski
authors.affiliation: Zaklad Antybiotyków i Mikrobiologii Narodowego Instytutu Leków w Warszawie.
authors.forename: Stefan
authors.initials: S
authors.lastname: Tyski
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000890:Anti-Infective Agents / Q000494:pharmacology*; D003731:Dental Caries / Q000188:drug therapy* / Q000382:microbiology*; D003773:Dental Plaque / Q000382:microbiology / Q000517:prevention & control; D004926:Escherichia coli / Q000187:drug effects; D006801:Humans; D008826:Microbial Sensitivity Tests; D053758:Nanoparticles / Q000627:therapeutic use*; D012834:Silver / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects; D013295:Streptococcus mutans / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D012834:Silver