The results of in vitro antibiotic combination on multidrug-resistant strains of E coli and K pneumoniae for synergistic rates for ceftazidime + amikacin was 43.33% and 35.71%; for ceftazidime + levofloxacin was 7.41% and 7.69%; for imipenem + levofloxacin was 70% and 60%; the synergistic rate for imipenem + amikacin was 0%.