Ceftazidim – uchinchi avlod sefalosporinlar guruhiga kiruvchi antibakterial preparat bo‘lib, keng ta'sir doirasiga ega va bakteritsid ta'sir ko‘rsatadi, mikroorganizmlarning hujayra devori sintezini buzadi va ko‘pgina beta-laktamazlarning ta’siriga chidamli. Preparat grammusbat mikroorganizmlarga qarshi faol: Haemophilus influenzae, Neisseria gonorrhoeae va boshqa Neisseria spp. va Enterobacteriaceae oilasining ko'pchiligi (masalan, Citrobacter spp., Enterobacter spp., Escherichia coli, Klebsiella pneumoniae va boshqa Klebsiella spp., Morganella morganii va boshqa Morganella spp., Proteus mirabilis, shu jumladan indol-ijobiy, Proteus vulgaris va boshqa Proteus spp., Providencia rettgeri va boshqa Providencia spp. va Serratia spp.), Acinetobacter spp., Haemophilus parainfluenzae (ampitsillinga chidamli shtammlar kiritilgan), Pasteurella multocida, Salmonella spp., Shigella spp., Yersinia enterocolitica.
Ceftazidim uchinchi avlod sefalosporinlar ichida Pseudomonas aeruginosa va kasalxona infeksiyalariga qarshi eng yuqori faollikka ega. Preparat grammusbat bakteriyalarga qarshi faol: Micrococcus spp., Streptococcus aureus, Streptococcus mitis, Streptococcus pneumoniae, Streptococcus pyogenes A guruhi, Streptococcus viridans va boshqa Streptococcus spp. (shu jumladan Streptococcus faecalisdan tashqari); metitsillinga sezgir shtammlar: Staphylococcus aureus, Staphylococcus epidermidis.
Ceftazidim anaerob bakteriyalarga qarshi faol: Bacteroides spp. (ko‘pgina Bacteroides fragilis shtammlari chidamli), Clostridium perfringens, Peptococcus spp., Peptostreptococcus spp., Propionibacterium spp. Preparat metitsillinga chidamli shtammlarga nisbatan faol emas: Campylobacter spp., Chlamydia spp., Clostridium difficile, Enterococcus spp., Listeria monocytogenes va boshqa Listeria spp., Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus faecalis.