It has a good antibacterial effect on human tuberculosis bacteria, and its bactericidal effect is strongest at pH 5-5.5. It is currently the best bactericidal drug for tuberculosis bacteria that grow slowly in phagocytes in an acidic environment. The antibacterial concentration in vivo is 12.5 mu; g/ml, and 50 mu; g/ml can kill tuberculosis bacteria. The concentration that inhibits tuberculosis bacteria inside cells is 10 times lower than that outside cells, and it has almost no antibacterial effect in neutral and alkaline environments. The mechanism of action may be related to pyrazinoic acid. After pyrazinamide penetrates into phagocytes and enters the tuberculosis bacteria, the amidase in the bacteria removes the amide group and converts it into pyrazinoic acid to exert an antibacterial effect. In addition, because pyrazinamide is similar to nicotinamide in chemical structure, it interferes with dehydrogenase by replacing nicotinamide, prevents dehydrogenation, and hinders the use of oxygen by tuberculosis bacteria, which affects the normal metabolism of bacteria and causes death.

This product has a broad-spectrum antibacterial effect, especially high antibacterial activity against aerobic Gram-negative bacilli. It has good antibacterial activity in vitro against the following bacteria: most bacteria of the Enterobacteriaceae family, including Citrobacter, cloacae, Enterobacter aerogenes, Escherichia coli, Klebsiella, Proteus, Salmonella, Shigella, Vibrio, Yersinia, etc. It often has antibacterial activity against multi-drug resistant bacteria. It has high antibacterial activity against penicillin-resistant Neisseria gonorrhoeae, enzyme-producing Haemophilus influenzae and Moraxella. It has antibacterial activity against most strains of Pseudomonas such as Pseudomonas aeruginosa. This product has antibacterial activity against methicillin-sensitive Staphylococcus, and only moderate antibacterial activity against Streptococcus pneumoniae, hemolytic Streptococcus and Enterococcus faecalis. It also has good effects on Chlamydia trachomatis, Mycoplasma, Legionella, and antibacterial activity against Mycobacterium tuberculosis and atypical mycobacteria. Poor antibacterial activity against anaerobic bacteria. Ciprofloxacin is a bactericide that acts on the A subunit of bacterial DNA gyrase, inhibiting DNA synthesis and replication, leading to bacterial death.

It inhibits bacterial cell wall synthesis and has good antibacterial activity against Staphylococcus aureus, Staphylococcus epidermidis, various groups of streptococci, pneumococci, some Escherichia coli, Klebsiella, Proteus mirabilis and influenza bacilli. It is stable to penicillinase produced by Staphylococcus aureus and has good antibacterial effect on penicillin-resistant Staphylococcus aureus.

The antibacterial property is similar to that of cefazolin, and it has good antibacterial effect on Staphylococcus, Streptococcus pyogenes, Streptococcus pneumoniae, Escherichia coli, Proteus mirabilis, Haemophilus influenzae, etc.