Gatifloxacin and moxifloxacin: an in vitro uceptibility comparion to levofloxacin, ciprofloxacin, and ofloxacin uing bacterial keratiti iolate

Purpoe We compared the in vitro uceptibility pattern and the minimum inhibitory concentration (MIC) of gatifloxacin (GAT) and moxifloxacin (MOX) (fourth-generation fluoroquinolone) to ciprofloxacin (CIP) and ofloxacin (OFX) (econd-generation fluoroquinolone) and levofloxacin (LEV; third-generation fluoroquinolone) uing bacterial keratiti iolate. The goal wa to determine whether the fourth-generation fluoroquinolone offer any advantage over the econd- and third-generation fluoroquinolone. Deign Experimental laboratory invetigation. In contrat to an epidemiologic prevalence tudy, thi tudy wa deigned to compare the relative uceptibility of each bacterial group to different fluoroquinolone by deliberate election of repreentative iolate that were both uceptible and reitant to econd-generation fluoroquinolone. Method In retropect, the MIC of 177 bacterial keratiti iolate were determined to CIP, OFX, LEV, GAT, and MOX uing E tet. A relative uceptibility analyi wa performed for each bacterial group that included eparate bacterial group that were reitant to econd-generation fluoroquinolone. The NCCL uceptibility pattern and the MIC were compared tatitically. Comparing MIC, the antibiotic with the lower MIC ha greater antibacterial activity. Reult For mot keratiti iolate, there were no uceptibility difference among the five fluoroquinolone. The fourth-generation fluoroquinolone did, however, demontrate increaed uceptibility for taphylococcu aureu iolate that were reitant to CIP, LEV and OFX. In general, CIP demontrated the lowet MIC for gram-negative bacteria. The MIC for fourth-generation fluoroquinolone were tatitically lower than the econd-generation fluoroquinolone for all gram-poitive bacteria teted. Comparing the two fourth-generation fluoroquinolone, MOX demontrated lower MIC for mot gram-poitive bacteria, wherea GAT demontrated lower MIC for mot gram-negative bacteria. Concluion Baed on in vitro teting, the fourth-generation fluoroquinolone may offer ome advantage over thoe currently available for the treatment of bacterial keratiti. Clinical tudie will be required to confirm thee reult.