First-generation cephalosporins have a broad antibacterial spectrum and are highly active against gram-positive bacteria. They are sensitive to penicillinase-producing and non-penicillinase-producing Staphylococcus aureus, coagulase-negative Staphylococci, Streptococcus pyogenes, Streptococcus pneumoniae, group B hemolytic Streptococci, viridans streptococci, Staphylococcus epidermidis, Corynebacterium diphtheriae, and Bacillus anthracis; highly sensitive to Haemophilus influenzae, Neisseria meningitidis, Moraxella catarrhalis, and Neisseria gonorrhoeae; moderately sensitive to some strains of Escherichia coli, Klebsiella, Salmonella, Shigella, and Proteus; sensitive to gram-positive anaerobic bacteria, and resistant to Bacteroides fragilis. They mainly inhibit the synthesis of bacterial cell walls.

It has high antibacterial activity against most aerobic Gram-negative bacteria, including Escherichia coli, Klebsiella pneumoniae and Oxytobacter, Aerobacter, Cloacae, Proteus, Serratia, Citrobacter, Shigella and other Enterobacteriaceae, as well as influenza bacilli, gonococci, meningococci, etc. It also has good antibacterial effect against Pseudomonas aeruginosa, but has poor antibacterial effect against some Pseudomonas and Acinetobacter species other than Pseudomonas aeruginosa, and has no antibacterial activity against aerobic Gram-positive bacteria such as Staphylococcus and Streptococcus, as well as anaerobic bacteria. Aztreonam inhibits cell wall synthesis by highly binding to penicillin-binding protein 3 (PBP3) on the cell membrane of sensitive aerobic Gram-negative bacteria. Unlike most beta-lactam antibiotics, it does not induce bacteria to produce beta-lactamases, and is highly stable to most beta-lactamases produced by bacteria.

This product is a second-generation cephalosporin for intravenous or intramuscular injection. This product has a wider antibacterial spectrum against Gram-negative bacilli than the first-generation cephalosporins. It has good antibacterial activity similar to cefoxitin against Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Citrobacter, Providencia and Enterobacter, but its activity against indole-positive Proteus, Morganella, Providencia and some Klebsiella is lower than that of cefoxitin. It has satisfactory activity against gonococci of influenza bacilli, including beta-lactamase-producing strains. Like other second-generation cephalosporins, Pseudomonas, Serratia and Acinetobacter are resistant to this product. This product is effective against most Gram-positive cocci. Its activity against Staphylococcus aureus is similar to that of cefoxitin and cefuroxime, but lower than that of cefoxitin, cephalothin and cefazolin. 90% of the strains can be inhibited by this product at a concentration of 4.0 to 8.3 mg/L. Most streptococci, including Streptococcus pneumoniae, Streptococcus pyogenes and Group B Streptococcus, are sensitive to this product. Staphylococcus epidermidis is relatively resistant to this product. Streptococcus faecalis, Staphylococcus aureus and methicillin-resistant strains of Staphylococcus epidermidis are all resistant to this product. The activity of this product against anaerobic bacteria has not been well studied, and Bacteroides fragilis is resistant to this product. The minimum bactericidal concentration (MBC) of this product for Staphylococcus aureus, Group B Streptococcus and Escherichia coli is significantly higher than its minimum inhibitory concentration (MIC). This product is very stable to type I beta-lactamase, but can be slowly hydrolyzed by type IIIa, IIIb and V beta-lactamase, while only type IV beta-lactamase is sensitive.

It has a broad spectrum of antibacterial activity against Gram-positive and Gram-negative bacteria, especially against Escherichia coli, Klebsiella, Haemophilus influenzae, Proteus and Bacteroides fragilis. Its mechanism of action is that it shows a strong affinity for penicillin-binding protein, which is the usual point of action of β-lactam antibiotics, inhibits cell wall synthesis, binds to peptidoglycan, inhibits the binding of peptidoglycan to lipoprotein to promote bacteriolysis, and shows a strong bactericidal effect in a short time. This product shows antibacterial effect on bacteria during the proliferation period and the early stage of the stable period, and has a bactericidal effect at concentrations lower than the MIC, and lyses bacteria in a short time. The antibacterial effect in vivo is stronger than the prediction of the MIC.

It acts on the active reproduction stage of cells and has a bactericidal effect by inhibiting the biosynthesis of cell wall mucopeptides. It is effective against a variety of Gram-positive and Gram-negative bacteria.

It has weak inhibitory effect on bacteria and is a competitive irreversible beta-lactamase inhibitor. When used in combination with beta-lactam antibiotics, it can achieve good synergistic effects.