Activities of antimicrobial agents against intracellular pneumococci.

Pneumococci can enter and survive inside human lung alveolar carcinoma cells. We examined the activity of azithromycin, gentamicin, levofloxacin, moxifloxacin, penicillin G, rifampin, telithromycin, and trovafloxacin against pneumococci inside and outside cells. We found that moxifloxacin, trovafloxacin, and telithromycin were the most active, but only telithromycin killed all intracellular organisms.