gentamicin + oxacillin + piperacillin

This is a combination of three antibiotics—gentamicin, oxacillin, and piperacillin—used together for the treatment of severe or mixed bacterial infections. - **Gentamicin** is an aminoglycoside antibiotic that acts by binding to the 30S subunit of bacterial ribosomes, inhibiting protein synthesis and leading to cell death. It is particularly effective against aerobic gram-negative bacteria and shows synergistic effects when combined with beta-lactam antibiotics like penicillins[5]. - **Oxacillin** is a narrow-spectrum beta-lactam (penicillinase-resistant penicillin) antibiotic used primarily for infections caused by penicillinase-producing staphylococci (notably Staphylococcus aureus). It inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins. - **Piperacillin** is an extended-spectrum ureidopenicillin that inhibits bacterial cell wall synthesis; it has broad activity against both gram-positive and gram-negative organisms, including Pseudomonas aeruginosa[1][3]. Piperacillin may be used in combination with other agents for severe or hospital-acquired infections. The rationale for combining these agents includes broadening antibacterial coverage (covering both gram-positive—including resistant staphylococci—and gram-negative pathogens), exploiting potential synergistic effects between aminoglycosides and beta-lactams, and targeting polymicrobial or high-risk hospital-acquired infections.