ceftolozane-tazobactam + meropenem

Ceftolozane-tazobactam + meropenem is a combination of two antibacterial regimens used together, particularly for treating infections caused by multidrug-resistant (MDR) and extensively drug-resistant (XDR) gram-negative bacteria such as *Pseudomonas aeruginosa*. - **Ceftolozane-tazobactam** is a fixed-dose combination of ceftolozane, a cephalosporin antibiotic, and tazobactam, a β-lactamase inhibitor. Ceftolozane acts by inhibiting bacterial cell wall synthesis, while tazobactam protects ceftolozane from degradation by bacterial β-lactamases, thereby broadening its spectrum of activity especially against resistant bacteria[5]. - **Meropenem** is a carbapenem antibiotic with broad-spectrum activity, including many gram-negative and gram-positive organisms, and works by inhibiting the synthesis of the bacterial cell wall. The combination of ceftolozane-tazobactam and meropenem has demonstrated **synergistic bactericidal effects** against highly resistant *Pseudomonas aeruginosa* strains, showing sustained suppression of bacterial populations and resistance prevention in in vitro studies[1][6][7]. Clinical reports indicate the potential use of this combination for severe, resistant infections where monotherapy is insufficient[1][4][7].