Effects ofNew Quinolones on AMycoplasma pneumoniae-Infected

Theefficacies ofthenew quinolones temafloxacin, ofloxacin, andciprofloxacin were investigated against Mycoplasma pneumoniae inanexperimental hamster pneumonia model. Hamsters wereinfected intratracheally withM.pneumoniae andsacrificed 18h after thefinal medication, andtheir lungs were aseptically removed, homogenized, andcultured quantitatively. Theefficacies ofthese drugs were determined bytheCFUofM. pneumoniae inlungs. Temafloxacin andofloxacin, butnotciprofloxacin, wereactive whentheoral administration of200mg/kgofbodyweight perday(once perday)for5days was initiated 24hafter infection. Although noeffect on theelimination ofM.pneumoniae was observed after theadministration ofthese drugs at200mg/kg/day at 5 daysafter infection, thecontinuous administration for15daysoftemafloxacin, butnotofloxacin or ciprofloxacin, significantly reduced viable M.pneumoniae inthelungs. Theseresults suggest thattemafloxacin andofloxacin areeffective intheacutephase ofinfection and, moreover,that temafloxacin iseffective inthelate stage ofinfection during whichprogressive lungalterations andcontinuous increases inmycoplasmal growth occurred. Thepeaklevels oftemafloxacin inseraandlungs after oraladministration were similar tothose of ofloxacin andhigher thanthose ofciprofloxacin. Theareasunderthecurveoftemafloxacin inthelungtissue, however, werehigher thanthose ofofloxacin andciprofloxacin. Onthebasis ofthese results, temafloxacin and ofloxacin mightbepromising antimicrobial agents forthetreatment ofmycoplasmal infection.