In vitro analysis of the change in resistance of Chlamydia trachomatis under exposure to sub-MIC levofloxacin for a therapeutic term

Background: While fluoroquinolone-resistant Chlamydia trachomatis strains h ave not been clinically isolated, they were isolated in an in vitro study r ecently. Methods: To determine whether C, trachomatis strains develop resis tance under sub-MIG antibacterial exposure in a clinical therapeutic term, C, trachomatis strains were exposed to sub-MIG levofloxacin (LVFX) for abou t 2 weeks. The MIG of LVFX was measured and DNA fingerprinting was performe d every 72 h by PCR using random primers. Results: There was almost no chan ge in the MIG under exposure to 0.125 mug/ml LVFX. However, some mutation-a l changes in DNA fingerprints developed. Conclusions: In clinical therapeut ic terms, resistant strains of C, trachomatis will probably not develop, ev en if sub-MIG LVFX is employed, Copyright (C) 2000 S. Karger AG, Basel.