In vitro antichlamydial activity of moxifloxacin versus a range of antimicrobial agents

Abstract number: p715

Cevenini  R., Donati  M., Pignanelli  S., Accardo  S., Cavrini  F., Mazzeo  C.

Objectives: 

To test the in vitro activity of moxifloxacin (MXF) versus doxycycline (DOX), levofloxacin (LFX), clarithromycin (CLAR) and erythromycin (ERY) against C. trachomatis.

Materials: 

30 strains of C. trachomatis (10 typed and 20 untyped clinical isolates from urethral swabs of male patients with non-gonococcal urethritis) were tested. Susceptibility testing was performed in plated LLC-MK2 cells in supplemented Eagle's minimum essential medium. Plates were inoculated with chlamydiae that yielded 5×10³ inclusion forming units (IFU)/mL. Cultures were stained with fluorescein-conjugated monoclonal antibody specific for the chlamydial lipopolysaccharide genus-specific antigen. All antimicrobial agents were obtained as powders and solubilized according the instructions of manufacturers. Minimum inhibitory concentration (MIC; lowest concentration preventing >90% chlamydial inclusion detection compared with the drug-free control) and minimum bactericidal concentration (MBC; lowest antimicrobial concentration resulting in >90% reduction of inclusion) were determined.

Results: 

The results are shown in the Table. Of the fluoroquinolones, MXF was more active than LFX. Of the macrolides, CLAR was more active than ERY. MXF had the best bactericidal activity of all the compounds tested.

Conclusions: 

These data confirm the high activity of MXF versus C. trachomatis. Therefore, MXF is likely to be a suitable treatment for infections where C. trachomatis is a potential pathogen.