In Vitro and in Vivo Antibacterial Activity of Four Newly Developed Quinolone Agents against Legionella Infection

We investigated the antibacterial activity of four newly developed quinolone agents, temafloxacin (TMFX, TA-167), sparfloxacin (SPFX , AT -4140) , OPC -17116 and Y 26611 against Legionella was investigated both in vitro and in vivo and compared them with those of other quinolone agents and with erythromycin. In vitro strength of the antibacterial activity was found to be in the order of strongest to weakest, as follows: temafloxacin, ciprofloxacin, sparfloxacin, OPC-17116, Y-26611, ofloxacin, norfloxacin and erythromycin. The quinolones showed higher intracellular than extracellular concentration in human polymorphonuclear neutrophils. All quinolones and the erythromycin, at concentrations twice that of MIC, inhibited the growth of Legionella pneumophila in guinea pig peritoneal macrophages. In experimental L. pneumophila pneumonia in guinea pigs, the newly developed quinolone agents showed a significantly greater therapeutic effect than did the erythromycin.