ceftazidime + tobramycin

Ceftazidime + tobramycin is a combination antibiotic therapy that demonstrates synergistic activity against various bacterial infections, particularly those caused by Pseudomonas aeruginosa. This combination pairs a third-generation cephalosporin (ceftazidime) with an aminoglycoside (tobramycin) to provide enhanced antibacterial efficacy. The combination works through complementary mechanisms: - **Ceftazidime** inhibits bacterial cell wall synthesis by binding to specific penicillin-binding proteins (PBPs), particularly PBP3, with weaker binding to PBP1a/1b and PBP2. This disrupts the bacterial cell wall, leading to instability and bacterial death[8]. - **Tobramycin** binds to the bacterial 30S and 50S ribosome, preventing formation of the 70S complex. This inhibits protein synthesis, resulting in bacterial death. The disruption of the cell wall by ceftazidime enhances tobramycin uptake into the bacterial cell[6][10]. The synergistic effect occurs because ceftazidime's disruption of the cell wall allows tobramycin to enter the bacterial cell more easily, enhancing its ability to inhibit protein synthesis[10]. This synergism is particularly effective against hypermutable Pseudomonas aeruginosa strains, which are a major challenge in cystic fibrosis patients[1].