In vitro activity of Ro 23-9424, a dual-acting cephalosporin-quinolone antimicrobial agent.

In vitro activity of new dual-acting antibacterial Ro 23-9429 was tested against 1294 bacterial isolates from patients in a major tertiary care referral hospital in Saudi Arabia. Its activity was compared with that of ciprofloxacin, fleroxacin, ampicillin, cephalothin, cefoxitin, cefotaxime, ceftazidime, piperacillin, oxacillin, gentamicin, amikacin, imipenem, and vancomycin. Of the 621 members of Enterobacteriaceae tested, every single isolate was inhibited by Ro 23-9429 at minimum inhibitory concentration ranging between < .03 and 8 micrograms/mL. No other antimicrobial tested was as active as this dual-acting cephalosporin-fluoroquinolone. Similarly, all of the 255 isolates of Acinetobacter, Aeromonas hydrophila, Pseudomonas aeruginosa, and Xanthomonas maltophilia were susceptible to Ro 23-9429. It inhibited all the 120 isolates of methicillin-resistant Staphylococcus aureus. Its in vitro activity against coagulase-negative staphylococci and enterococci was superior or comparable to that of other drugs that are commonly used in clinical practice.