ANTIMICROBIAL ACTIVITY AND SPECTRUM OF SPARFLOXACIN TESTED AGAINST ERYTHROMYCIN-RESISTANT STREPTOCOCCUS-PNEUMONIAE ISOLATES

Recognition of a worldwide increase of penicillin-resistant Streptococ cus pneumoniae and cross-resistance to other classes of antimicrobials have placed a great urgency on the need for new antimicrobial agents. Sparfloxacin, a novel pyridone carboxylic acid fluoroquinolone deriva tive tons evaluated and compared to six other compounds for antimicrob ial activity against erythromycin-resistant pneumococci (50 strains). The Etest susceptibility testing method was used to inoculate Mueller- Hinton agar supplemented with 5% sheep blood. There was extensive cros s-resistance between erythromycin, clarithromycin (94%), and azithromy cin (100%), but no cross-resistance was detected between macrolides/az alides and sparfloxacin (all strains susceptible at less than or equal to 1.0 mu g/ml). Sparfloxacin (MIC(90), 1 mu g/ml) was four-fold more active than ciprofloxacin and ofloxacin (MIC(90), 4 mu g/ml). Sparflo xacin appears to possess excellent in vitro activity against erythromy cin-resistant S. pneumoniae that were often highly resistant to beta-l actams, and further studies are recommended to investigate its in vivo efficacy against these multi-resistant organisms.