Comparative in vitro activity of Ro 09-1428, a novel cephalosporin with a catechol moiety

The in vitro activity of Ro 09-1428, a new parenteral cephalosporin, was compared with that of other beta-lactams and aminoglycosides in 1230 clinical isolates from 1028 consecutive patients. Using an agar dilution method, the drugs were tested against 625 isolates of Enterobacteriaceae, 68 Pseudomonas aeruginosa, 36 Xanthomonas maltophilia, 20 Aeromonas hydrophila, 54 Acinetobacter, 373 staphylococci, and 54 strains of enterococci. More than 98% of Enterobacteriaceae were susceptible to Ro 09-1428, with a minimal inhibitory concentration of less than 0.03 to 4.0 micrograms/ml. Ro 09-1428 also inhibited 99% and 72% of the clinical isolates of P aeruginosa and X maltophilia, respectively. All isolates of methicillin-susceptible Staphylococcus aureus (MSSA) were susceptible to this cephalosporin. However, only 46% of the 54 strains of enterococci exhibited in vitro susceptibility. Ro 09-1428 was found to be superior or comparable to most penicillins, cephalosporins, and aminoglycosides against both gram-negative bacteria and MSSA.