NAD+ auxotrophy is bacteriocidal for the tubercle bacilli

Catherine Vilchèze, Brian Weinrick, Ka Wing Wong, Bing Chen, William Jacobs

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


Summary The human tubercle bacillus Mycobacterium tuberculosis can synthesize NAD+ using the de novo biosynthesis pathway or the salvage pathway. The salvage pathway of the bovine tubercle bacillus Mycobacterium bovis was reported defective due to a mutation in the nicotinamidase PncA. This defect prevents nicotinic acid secretion, which is the basis for the niacin test that clinically distinguishes M. bovis from M. tuberculosis. Surprisingly, we found that the NAD+de novo biosynthesis pathway (nadABC) can be deleted from M. bovis, demonstrating a functioning salvage pathway. M. bovis ΔnadABC fails to grow in mice, whereas M. tuberculosis ΔnadABC grows normally in mice, suggesting that M. tuberculosis can acquire nicotinamide from its host. The introduction of M. tuberculosis pncA into M. bovis ΔnadABC is sufficient to fully restore growth in a mouse, proving that the functional salvage pathway enables nicotinamide acquisition by the tubercle bacilli. This study demonstrates that NAD+ starvation is a cidal event in the tubercle bacilli and confirms that enzymes common to the de novo and salvage pathways may be good drug targets.

Original languageEnglish (US)
Pages (from-to)365-377
Number of pages13
JournalMolecular Microbiology
Issue number2
StatePublished - Apr 2010

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology


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