[Synergistic action of cefodizime and other antimicrobial agents on clinically isolated microorganisms. IV. Synergistic action with dibekacin].

Antimicrobial activities of cefodizime (CDZM) in combination with dibekacin (DKB) were studied in vitro against clinically isolated Gram-negative rods. The results obtained are summarized as follows. 1. Similarly to combinations of CDZM+sisomicin (SISO) and CDZM+gentamicin (GM), combined activities of CDZM and DKB were dependent on antimicrobial activities of DKB, and the combined activities were more strongly dependent on DKB concentrations than on CDZM concentrations. The obtained results suggested that synergistic or cooperative antimicrobial activities of the combination would be expected when DKB concentrations in blood are at or somewhat lower than 1 MIC, and that clinical activities would be exerted regardless of the presence of CDZM resistant organisms, similarly to CDZM+GM combination. 2. As we have suggested previously, it seems possible that, with regard to combinations of beta-lactam antibiotics and aminoglycoside antibiotics, there exist universal rules that combined activities are dependent on activities of aminoglycoside antibiotics, and that stronger concentration dependencies on aminoglycosides would be observed than those on beta-lactams.