In vitro activities of new beta-lactam antibiotics against Acinetobacter spp

The in vitro activities of new beta-lactam antibiotics was studied and compared with those of other known agents against 51 clinical isolates of Acinetobacter calcoaceticus subsp. anitratus and 23 isolates of A. calcoaceticus subsp. lwoffi. Of the new beta-lactam antibiotics, imipemide (N-formimidoyl thienamycin), ceftazidime, ceftizoxime, ceftriaxone, and piperacillin demonstrated good activities. The minimal inhibitory concentrations for A. calcoaceticus subsp. lwoffi were lower than those obtained for A. calcoaceticus subsp. anitratus.