Objective To investigate and evaluate the characteristics of in vitro antibacterial activity of cefotaxime,cefoperazone,ceftriaxone,ceftazidime,cefuroxime
and cefazolin for injection. Methods MICs of six
cephalosporins against 194 clinical isolates,including 41 extended-spectrum β-lactamase producing isolates,121 β-lactamase producing isolates and 73 β-lactamase non-producing isolates,were determined by agar dilution method. Activity of β-lactamases and the relative rates of hydrolysis of these antibiotics were determined by ultra violet spectrophotometry. Results The in vitro antibacterial activities of the third generation of cephalosporins were stronger than the second generation. The in vitro antibacterial activities of cephalosporins against gram-negative bacteria were stronger than against gram-positive bacteria. The results of β-lactamases hydrolysis showed that the hydrolysis relative rates of cefotaxime,
cefoperazone,ceftriaxone and ceftazidime were between 40% and 90%,which were lower than those of cefuroxime and cefazolin agaist SHV-1,SHV-2,SHV-4,SHV-5,TEM-1,TEM-5 and D31. Conclusion The third generation of cephalosporins are still the best choice for clinical infection treatment,and it is worthy of further validation and exploitation for the combination with β-lactamase inhibitors.