This Phase IIb study aims to evaluate the safety and efficacy of BV100 in combination with low dose polymyxin B plus ceftazidime/avibactam or cefiderocol in patients with suspected or confirmed CRABC infections. The study is divided into two parts (Part A and Part B), recruiting in parallel. Approximately 10 subjects will be recruited in Part B, with enrollment ending once Part A enrollment is complete (at least 30 patients randomized to all of the three groups). Eligible patients, who have given informed consent, will be enrolled, and pre-treatment microbiology samples submitted to a local laboratory.