Bactericidal activity of nitrofurans against growing and dormant Mycobacterium bovis BCG.

Depletion of oxygen triggers the shift-down of Mycobacterium bovis BCG to a state of dormancy. Bacilli in their dormant state are resistant to standard anti-mycobacterials. The nitroimidazole metronidazole was the first compound identified to show bactericidal activity against dormant tubercle bacilli. In contrast to metronidazole's selective toxicity for dormant bacilli, we report here that the nitrofurans nitrofurantoin, furaltadone and nitrofurazone showed bactericidal activity against dormant and growing bacteria. Importantly, the bactericidal effect of nitrofurans on dormant bacilli was 35- to 250-fold higher compared with metronidazole.