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

## TL;DR

A patient with a rare bacterial meningitis was successfully treated using a combination of aztreonam and avibactam, which overcame drug resistance.

## Contribution

Demonstrates the successful use of aztreonam-avibactam for Stenotrophomonas maltophilia meningitis by overcoming resistance mechanisms.

## Key findings

- Aztreonam and avibactam showed favorable cerebrospinal fluid-to-plasma ratios.
- Avibactam effectively inhibits L2 serine β-lactamases, restoring aztreonam's activity.
- The combination successfully treated S. maltophilia meningitis in a clinical case.

## Abstract

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.