Objective To investigate the in vitro
antibacterial activity of azlocillin and other commonly used antibiotics.Methods The
minimum inhibitory concentration(MIC) of azlocillin,mezlocillin,piperacillin,cefuroxi me,ceftriaxone,ceftazidime,cefoperazone,levofloxacinand azithromycin against 898 bacteria isolated in Shanghai and Beijing were determined by agar dilution method.Results The MIC50/ MIC90 of azlocillin against Streptococcus pneumoniae,Haemophilus influenzae and methicillin-sensitive Staphylococcus aureus(MSSA) was 0.06/2,0.06/0.5 and 2/8,respectively.The
susceptibility of these three species against azlocillin was all 100%.The susceptibility of Enterococcus faecalis,Enterococcus faecium,Pseudomonas aeruginosa and Acinetobacter spp.to azlocillin was 91%,13%,68% and 38% respectively,making azlocillin rank the top1,1 and 3 active agent among tested antibiotics.The susceptibility of Escherichia coli,Klebsiella pneumoniae and Enterobacter cloacae against azlocillin was 41%,65% and 39%,respectively.It was higher than other penicillins,while lower than the third generation cephalosporins.Conclusions Azlocillin had a wide antimicrobial spectrum and good in vitro
antibacterial activity against Gram-positive and Gram-negative bacteria.It's suggested that azlocillin was one of the active antibiotics used in community and hospital acquired infection.