Ceftolozane-tazobactam is currently the most active antipseudomonal agent, including multidrug-resistant extensively drug-resistant strains. Tazobactam provides additional activity against many extended-spectrum beta-lactamases Enterobacterales. Ceftolozane-tazobactam is formally approved for complicated urinary tract infection, complicated intra-abdominal infection, and hospital-acquired and ventilator-associated bacterial pneumonia. The clinical and microbiological success is over 70-80% in many series. However, resistant mutants to ceftolozane-tazobactam have been already described. Combination therapies with colistin or meropenem could be among the strategies to avoid the resistance emergence.