OBJECTIVE: To study the in vitro activities of the ?-lactamase inhibitor sulbactam combined with ceftazidime,
cefotaxime,
cefuroxime at the ratio of 1:1 against ceftazidime or cefuroxime resistant gram-negative rods and S.aureus. METHODS: The in vitro
combination antibacterial activities were studied by using two-fold plate dilution methods. RESULTS: The results showed sulbactam could enhance the antibacterial activities of ceftazidime,
cefotaxime, cefuroxime against gram-negative rods. It could decreased the MIC90 of ceftazidime against E.coli, E.cloacae, C.freundii, Acinetobacter spp., P.aeruginosa 4 folds and reduced the MIC90 of cefotaxime against E.coli, E.cloacae, C.freundii, Acinetobacter spp. 2~4 folds. However, sulbactam couldn誸 enhance the activities of ceftazidime, cefotaxime, cefuroxime against S.aureus, Enterococcus and Stenotrophomonas maltophilia. 38.4% of ceftazidime resistant E.coli, 45.3% of ceftazidime resistant E.cloacae, 66.6% of ceftazidime resistant C.freundii and 60% of ceftazidime resistant Acinetobacter spp were susceptible to the combination of sulbactam and ceftazidime at the ratio of 1:1. CONCLUSION: Sulbactam could enhance the activity of ceftazidime against 30%~40% ceftazidime resistant bacteria.