Colorimetric microbial viability assay based on reduction of water-soluble tetrazolium salts for antimicrobial susceptibility testing and screening of antimicrobial substances.
The applicability of a colorimetric microbial viability assay based on reduction of a tetrazolium salt {2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt [WST-8]} via 2-methyl-1,4-naphthoquinone (2-methyl-1,4-NQ) as an electron mediator for determining the susceptibility of various bacteria to antibiotics and screening antimicrobial substances was investigated. The measurement conditions, which include the effects of the concentration of 2-methyl-1,4-NQ, were optimized for proliferation assays of gram-negative bacteria, gram-positive bacteria, and pathogenic yeast. In antimicrobial susceptibility testing, there was excellent agreement between the minimum inhibitory concentrations determined after 8 h using the WST-8 colorimetric method and those obtained after 22 h using conventional methods. The results suggest that the WST-8 colorimetric assay is a useful method for rapid determination of the susceptibility of various bacteria to antibiotics. In addition, the current method was applied to the screening of bacteriocin-producing lactic acid bacteria and its efficiency was demonstrated.
Tsukatani
Tadayuki
T
Biotechnology and Food Research Institute, Fukuoka Industrial Technology Center, Kurume 839-0861, Japan. tukatani@fitc.pref.fukuoka.jp
Higuchi
Tomoko
T
Suenaga
Hikaru
H
Akao
Tetsuyuki
T
Ishiyama
Munetaka
M
Ezoe
Takatoshi
T
Matsumoto
Kiyoshi
K
D000900:Anti-Bacterial Agents / Q000032:analysis* / Q000494:pharmacology; D001430:Bacteriocins / Q000096:biosynthesis; D003124:Colorimetry / Q000379:methods*; D055808:Drug Discovery / Q000379:methods*; D050296:Microbial Viability / Q000187:drug effects; D015394:Molecular Structure; D012995:Solubility; D013778:Tetrazolium Salts / Q000032:analysis* / Q000737:chemistry; D014867:Water / Q000737:chemistry*
D000900:Anti-Bacterial Agents; D001430:Bacteriocins; D013778:Tetrazolium Salts; D014867:Water