title: A new method for antimicrobial susceptibility testing of in vitro-cultured bacteria by means of resonance light scattering technique.
abstract: A new method for antimicrobial susceptibility testing of in vitro-cultured bacteria on an ordinary fluorescence spectrometer was developed. The viable bacteria reduced 3- (4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) to produce insoluble particles that displayed intense resonance scattering light (RSL). The assay showed a linear relationship between the number of viable bacteria and the intensity of resonance scattering light. Dead bacteria were unable to reduce MTT. Methicillin-resistant Staphylococcus aureus exposed to flavonoids from Marchantia convoluta showed a flavonoids concentration-dependent inhibition of the ability to reduce MTT. In the assay, less than 12 h were required to attain susceptibility results and fewer bacteria were utilized than in traditional methods. The RLS technique could, in combination with the MTT assay, be a rapid and sensitive measuring method to determine the in vitro activity of new antimicrobials.
authors.affiliation: School of Chemistry and Chemical Engineering, Nantong University, Nantong, Jiangsu 226000, PR China. jnb_xiao@yahoo.com
authors.forename: Yu Jun
authors.initials: YJ
authors.lastname: Shi
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
authors.forename: Ming
authors.initials: M
authors.lastname: Xu
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D004396:Coloring Agents / Q000378:metabolism; D005419:Flavonoids / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D008027:Light; D047008:Marchantia / Q000737:chemistry; D016106:Methicillin Resistance; D008826:Microbial Sensitivity Tests / Q000379:methods*; D010084:Oxidation-Reduction; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D012542:Scattering, Radiation; D013050:Spectrometry, Fluorescence / Q000295:instrumentation; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000378:metabolism; D013778:Tetrazolium Salts / Q000378:metabolism; D013844:Thiazoles / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D004396:Coloring Agents; D005419:Flavonoids; D010936:Plant Extracts; D013778:Tetrazolium Salts; D013844:Thiazoles; C022616:thiazolyl blue