title: Activity of a new cephalosporin antibiotic, Ro 13-9904 against dense populations of selected enterobacteria.
abstract: Ro 13-9904 is a new cephalosporin antibiotic with a wide spectrum of activity similar to that of cefotaxime and some other newer beta-lactam compounds. In the present study, the response to Ro 13-9904 of 13 strains of enterobacteria, selected on the basis of differential patterns of susceptibility to beta-lactam agents, was investigated. The new cephalosporin displayed high intrinsic activity against most of the enterobacteria tested, but a group of Klebsiella and Hafnia alvei strains was identified against which Ro 13-9904 (and cefotaxime) exhibited reduced activity. Investigation of these strains revealed several different types of response to Ro 13-9904 and cefotaxime. Although such "difficult" strains represent a small minority of clinical isolates, it is likely that it is this group of strains against which the new generation of highly potent, broad-spectrum beta-lactam antibiotics will display significant differential activity.
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001433:Bacteriolysis / Q000187:drug effects; D002443:Ceftriaxone; D002511:Cephalosporins / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D004755:Enterobacteriaceae / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D009391:Nephelometry and Turbidimetry
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D002443:Ceftriaxone