Case Commentary: Overcoming intrinsic resistance-the successful use of aztreonam and avibactam for Stenotrophomonas maltophilia meningitis.

Wong-So and colleagues describe a case of post-neurosurgical Stenotrophomonas maltophilia meningitis successfully managed with ceftazidime-avibactam and aztreonam. While aztreonam is stable against L1 metallo-β-lactamase-mediated hydrolysis, it remains susceptible to L2 serine β-lactamases, which are effectively inhibited by avibactam, restoring aztreonam's bactericidal activity. Simultaneous peak and trough levels in cerebrospinal fluid (CSF) and plasma demonstrated favorable CSF-to-plasma ratios for both aztreonam and avibactam. This case highlights aztreonam-avibactam as a rational therapeutic strategy for S. maltophilia meningitis.