Meropenem is a synthetic broad-spectrum carbapenem antibiotic that produces antibacterial effects by inhibiting the synthesis of bacterial cell walls. It easily penetrates the cell walls of most Gram-positive and Gram-negative bacteria and acts on penicillin-binding proteins (PBPs). It has strong stability against most β-lactamases (including penicillinase and cephalosporinase produced by Gram-positive and Gram-negative bacteria), but is not suitable for the treatment of methicillin-resistant Staphylococcus infections, and sometimes shows cross-resistance to other carbapenem-resistant strains. In vitro tests have shown that meropenem and aminoglycoside antibiotics can produce synergistic effects on some isolated strains of Pseudomonas aeruginosa. Meropenem exhibits antibacterial activity against a variety of Gram-positive aerobic bacteria, Gram-negative aerobic bacteria and anaerobic bacteria.

It has high antibacterial activity against most aerobic Gram-negative bacteria, including Escherichia coli, Klebsiella pneumoniae and Oxytobacter, aerogenes, 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 exerts its bactericidal effect by binding to penicillin-binding protein 3 (PBP3) on the cell membrane of sensitive aerobic Gram-negative bacteria and inhibiting the synthesis of bacterial cell walls.

It has high antibacterial activity against most aerobic Gram-negative bacteria, including Escherichia coli, Klebsiella pneumoniae and Oxytobacter, aerogenes, 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 binds to penicillin-binding protein 3 (PBP3) on the cell membrane of sensitive aerobic Gram-negative bacteria, interfering with the synthesis of bacterial cell walls, thereby achieving a bactericidal effect.