Ro 41-1879

The antimicrobial activity and spectrum of Ro 41-1879, a new 7'-catechol substituted cephalosporin, was assessed in a broth microdilution system against 312 clinical isolates. Ro 41-1879 demonstrated a slightly superior spectrum of activity (2- to 32-fold) compared to ceftazidime against Gram-positive cocci, Pseudomonas spp. and Xanthomonas maltophilia. Enterobacteriaceae strains were more susceptible (97% versus 96%) to ceftazidime at less than or equal to 16 micrograms/ml. These results represent a preliminary potency/spectrum analysis for Ro 41-1879 since the screening studies were performed with an in vitro system unlikely to detect the potency contributed by active drug transport (tonB system) into bacterial cells. This new class of cephalosporins shows some therapeutic promise.