USE OF OXIDATION-REDUCTION DYES IN THE DETERMINATION OF VIRULENCE OF MYCOBACTERIA INVITRO

Abstract

These workers describe a spot-plate virulence test utilizing organisms from a solid medium suspended in solns. of oxidation-reduction dyes. Virulent strains of Mycobacterium showed almost identical o-r curves throughout growth period. Attenuated strains presented curves different from those produced by virulent or avirulent strains. Redox dyes having an Eo potential of approx. -0.2 volts would be decolorized by avirulent strains but would not be affected by virulent strains of tubercle bacilli. Dyes used were: phenol indophenol, Na benzenone-indophenol, Na benzenoneindo-3[image]-chlorophenol, and sodium-2,6-dibromo-benzenone-indophenol. Nonviable or contaminated cultures gave false results. The authors suggest further study before test is adopted for routine use.