Intramacrophage passage of Mycobacterium tuberculosis and M. avium complex alters the drug susceptibilities of the organisms as determined by intracellular susceptibility testing using macrophages and type II alveolar epithelial cells

Antimicrob Agents Chemother. 2002 Feb;46(2):519-21. doi: 10.1128/AAC.46.2.519-521.2002.


Mycobacterium tuberculosis and M. avium complex strains given intramacrophage passage (I-type) were compared with those cultured in a liquid medium (E-type) for their drug susceptibilities when they were replicating in Mono-Mac-6 macrophages or A-549 cells. Their intracellular susceptibilities to rifalazil, clarithromycin, and levofloxacin were decreased more in I-type organisms than in E-type organisms, except that their rifalazil susceptibility inside A-549 cells was markedly increased in I-type organisms.

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • Antibiotics, Antitubercular / pharmacology
  • Cells, Cultured
  • Clarithromycin / pharmacology
  • Epithelial Cells / microbiology*
  • Humans
  • Levofloxacin
  • Macrophages / microbiology*
  • Microbial Sensitivity Tests
  • Mycobacterium avium Complex / drug effects*
  • Mycobacterium tuberculosis / drug effects*
  • Ofloxacin / pharmacology
  • Rifamycins / pharmacology


  • Anti-Bacterial Agents
  • Antibiotics, Antitubercular
  • Rifamycins
  • KRM 1648
  • Levofloxacin
  • Ofloxacin
  • Clarithromycin