title: Determination of bactericidal activity of antibacterial monomer MDPB by a viability staining method.
abstract: In this study, the bactericidal activity of antibacterial monomer MDPB (12-methacryloyloxydodecylpyridinium bromide) against Streptococcus mutans was tested by a rapid method for monitoring viability. To S. mutans culture containing fluorescence staining solution that distinguishes live from dead cells, MDPB was added at a concentration of 250, 100, 50, or 10 microg/ml. Bacterial cells were observed by fluorescence microscopy and the percentage of dead cells was calculated. After 10, 20, or 30 minutes' contact with MDPB, the live/dead ratio was measured by fluorometry and viable counts (CFU) determined by the conventional plating method. Viability staining revealed that MDPB exhibited significant bactericidal effects at 50 microg/ml or greater (ANOVA, Fisher's PLSD test), and complete killing of the cells at 250 microg/ml of MDPB was demonstrated in conjunction with a plating method. The staining method thus provided a sensitive means to determine loss of viability, and indicated the strong killing effects of MDPB on S. mutans.
authors.affiliation: Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan. imazato@dent.osaka-u.ac.jp
authors.forename: Satoshi
authors.initials: S
authors.lastname: Imazato
authors.forename: Kaoru
authors.initials: K
authors.lastname: Ohmori
authors.forename: Roy R B
authors.initials: RR
authors.lastname: Russell
authors.forename: John F
authors.initials: JF
authors.lastname: McCabe
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Momoi
authors.forename: Nobuko
authors.initials: N
authors.lastname: Maeda
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology*; D015169:Colony Count, Microbial; D003764:Dental Materials / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005456:Fluorescent Dyes; D006801:Humans; D008422:Materials Testing; D008856:Microscopy, Fluorescence; D011726:Pyridinium Compounds / Q000008:administration & dosage / Q000494:pharmacology*; D013295:Streptococcus mutans / Q000187:drug effects*; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D003764:Dental Materials; D005456:Fluorescent Dyes; D011726:Pyridinium Compounds; C089392:methacryloyloxydodecylpyridinium bromide