Enhanced in vitro bactericidal activity of amikacin or gentamicin combined with three new extended-spectrum cephalosporins against cephalothin-resistant members of the family Enterobacteriaceae.

摘要: The in vitro bactericidal interactions of three new extended-spectrum cephalosporins (ceftriaxone, ceftizoxime, or ceftazidime) combination with gentamicin amikacin were compared against 40 recent nosocomial bloodstream Enterobacteriaceae isolates by the timed-kill curve technique. All study strains cephalothin resistant, and 56% resistant to cefamandole. Combinations aminoglycosides plus ceftriaxone ceftizoxime exhibited an enhanced effect highest frequency (approximately 85 90%), whereas gentamicin-ceftazidime combinations demonstrated lowest (for 60% assays, P less than 0.0005 nonceftazidime regimens). effects occurred within readily achievable drug levels serum for all single antibiotic constituents. No antagonism was observed. There no discernible relationship between relative susceptibilities ceftazidime potential demonstrate activity. In 14 (35%) six tested effect. nearly 50% which resulted at 24 h, such killing clearly demonstrable 4 h incubation. These results delineate a frequent rapid enhancement activity extended-spectra members family Enterobacteriaeceae.