Acinetobacter baumannii (AB) is a non-fermenting gram-negative bacillus, largely opportunistic, ubiquitous in the environment, with the ability to survive in adverse environmental conditions, promoting its persistence and dissemination in different areas of the hospital. It has been implicated in many outbreaks of healthcareassociated infections such as pneumonia, bacteremia, surgical wound contamination, or urinary tract infections, especially among patients with previous severe illnesses such as those requiring admission to intensive care units (ICU). The most problematic strains are those resistant to carbapenems, resistance caused by chromosomal or plasmid oxacillinase class (bla OXA), and more recently bla NDM-1. The appearance of these strains leaves few active antimicrobials (Colistin, Minocycline, Tigecycline; Amikacin) that are limited in their efficacy and toxic. To this, we must add, as is the case of our patient who presented post-surgical meningitis, the limited diffusion capacity in the central nervous system (CNS) of these last options. One of the therapeutic alternatives is to search for synergistic associations such as sulbactam/avibactam that showed rapid synergistic and bactericidal activity in isolates resistant to ampicillin/sulbactam due to a significant reduction in its MIC, which allows us to administer usual, better-tolerated doses that reach therapeutic concentrations in CNS. Here, we present a patient who developed post-surgical meningitis due to multi-resistant AB.