biostudies-literatureUnknown81(1)Vlaspolder GLStenotrophomonas maltophilia is naturally resistant to many antimicrobials. We evaluated the in vitro activity and reproducibility of two different super-position methods of aztreonam in combination with ceftazidime-avibactam for S. maltophilia and compared these results with the recently available aztreonam-avibactam gradient strip. We recommend an improved super-position method that avoids the possible risk of handling a contaminated aztreonam strip. In addition, we report that the cefazidime-avibactam and aztreonam super-position method showed increased in vitro activity in comparison with aztreonam-avibactam indicating activity of the ceftazidime component in vitro.Current microbiology28https://www.ebi.ac.uk/biostudies/studies/S-EPMC10697871biostudies-literatureEnhancement and Comparison of (Ceftazidime-)Avibactam Plus Aztreonam Susceptibility Tests for Stenotrophomonas maltophilia in Clinical Diagnostics.PMC10697871Kampinga GAHuis In 't Veld RAGBathoorn EVlaspolder GLHughes LAfalseEnhancement and Comparison of (Ceftazidime-)Avibactam Plus Aztreonam Susceptibility Tests for Stenotrophomonas maltophilia in Clinical Diagnostics.Stenotrophomonas maltophilia is naturally resistant to many antimicrobials. We evaluated the in vitro activity and reproducibility of two different super-position methods of aztreonam in combination with ceftazidime-avibactam for S. maltophilia and compared these results with the recently available aztreonam-avibactam gradient strip. We recommend an improved super-position method that avoids the possible risk of handling a contaminated aztreonam strip. In addition, we report that the cefazidime-avibactam and aztreonam super-position method showed increased in vitro activity in comparison with aztreonam-avibactam indicating activity of the ceftazidime component in vitro.2023-01-01T00:00:00Z2023 Dec2025-04-04T13:57:56.463Z2025-04-04T13:57:56.463ZS-EPMC106978713805133810.1007/s00284-023-03530-7