Inhibition of Mycobacterium intracellulare by some vitamin K and coenzyme Q analogues.

Because vitamin K is present in several species of mycobacteria, and because coenzyme Q has been found to stimulate the growth of Mycobacterium tuberculosis and atypical mycobacteria, 8 quinones that can be considered to be dual analogues of vitamin K and coenzyme Q were tested for their activity against Mycobacterium intracellulare. One compound, 6-cyclo-octylamino-5,8-quinolinequinone (CQQ) exhibited considerable activity in vitro against several strains of Mycobacterium intracellulare at a concentration of 8 micrograms per ml. It has also shown evidence of bactericidal activity against growing cultures of Mycobacterium intracellulare. Time exposure studies indicated that a minimal contact period of 24 hours with a concentration of 8 micrograms of CQQ per ml is necessary for permanent inhibitory action against Mycobacterium intracellulare. At a concentration of 1 microgram per ml, CQQ inhibited Mycobacterium tuberculosis, including the rifampin-resistant strains. The drug has no activity against rapidly growing mycobacteria or organisms that are not acid-fast.