{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,14]],"date-time":"2026-10-14T18:59:26Z","timestamp":1792004366125,"version":"4.4.0"},"reference-count":20,"publisher":"Oxford University Press (OUP)","issue":"12","license":[{"start":{"date-parts":[[2025,10,13]],"date-time":"2025-10-13T00:00:00Z","timestamp":1760313600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/pages\/standard-publication-reuse-rights"}],"funder":[{"DOI":"10.13039\/501100001659","name":"Deutsche Forschungsgemeinschaft","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100001659","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100000780","name":"European Union","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100000780","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2025,12,2]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background and objectives<\/jats:title>\n                    <jats:p>MDR Pseudomonas aeruginosa is difficult to treat, despite some new beta-lactam\/beta-lactamase inhibitors. A combination of ceftazidime\u2013avibactam and aztreonam (CAZ\/AVI\u200a+\u200aAZT) is frequently used to treat Gram-negative bacteria expressing metallo-beta-lactamases. A fixed combination of aztreonam\/avibactam was recently licenced for use in Europe, but it remains unknown whether there are differences between both options for use against P. aeruginosa. This study evaluates the comparative in vitro efficacy of the fixed combination aztreonam\/avibactam compared to the three antibiotics CAZ\/AVI\u200a+\u200aAZT against clinical MDR P. aeruginosa isolates.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>MICs for aztreonam\/avibactam and CAZ\/AVI\u200a+\u200aAZT were determined in 38 MDR P. aeruginosa isolates recovered from routine diagnostics using broth microdilution with checkerboard assays in triplicates as the reference method. Fractional inhibitory concentration (FIC) indices were calculated. Whole-genome sequencing was performed on all isolates.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>At a fixed ceftazidime concentration of 8\u2005mg\/L (EUCAST breakpoint), 25 isolates exhibited lower MICs for CAZ\/AVI\u200a+\u200aAZT compared to aztreonam\/avibactam alone in microdilution assays. On FIC analysis, additive and synergistic effects were seen in 28 and 2 cases, respectively. Verona integron-encoded metallo-beta-lactamase (VIM) was the most prevalent carbapenemase (21\/38 isolates), followed by Imipenemase (IMP, 4\/38) and New Delhi metallo-beta-lactamase (NDM, 2\/38). Lower MICs were observed for the combination CAZ\/AVI\u200a+\u200aAZT in isolates carrying VIM-2 as compared to VIM-1.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>In vitro testing of CAZ\/AVI\u200a+\u200aAZT revealed increased in vitro susceptibility among MDR P. aeruginosa isolates in comparison to the fixed combination of aztreonam\/avibactam.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1093\/jac\/dkaf376","type":"journal-article","created":{"date-parts":[[2025,9,25]],"date-time":"2025-09-25T12:00:42Z","timestamp":1758801642000},"page":"3352-3356","source":"Crossref","is-referenced-by-count":8,"title":["Comparative\n                    <i>in vitro<\/i>\n                    activity of ceftazidime-avibactam plus aztreonam and the fixed combination aztreonam\/avibactam against multidrug-resistant\n                    <i>Pseudomonas aeruginosa<\/i>"],"prefix":"10.1093","volume":"80","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2280-534X","authenticated-orcid":false,"given":"Sophie E","family":"M\u00fcller","sequence":"first","affiliation":[{"name":"Institute of Medical Microbiology and Hygiene, Saarland University , Kirrberger Stra\u00dfe, Building 43, Homburg 66421 ,","place":["Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sabryna","family":"Junker","sequence":"additional","affiliation":[{"name":"Institute of Medical Microbiology and Hygiene, Saarland University , Kirrberger Stra\u00dfe, Building 43, Homburg 66421 ,","place":["Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jacqueline","family":"Rehner","sequence":"additional","affiliation":[{"name":"Institute of Medical Microbiology and Hygiene, Saarland University , Kirrberger Stra\u00dfe, Building 43, Homburg 66421 ,","place":["Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maximilian","family":"F\u00f6rster","sequence":"additional","affiliation":[{"name":"Institute of Medical Microbiology and Hygiene, Saarland University , Kirrberger Stra\u00dfe, Building 43, Homburg 66421 ,","place":["Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5361-0895","authenticated-orcid":false,"given":"Andreas","family":"Keller","sequence":"additional","affiliation":[{"name":"Clinical Bioinformatics, Saarland University, Saarbr\u00fccken 66123 ,","place":["Germany"]},{"name":"Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) , Saarland University Campus, Saarbr\u00fccken ,","place":["Germany"]},{"name":"PharmaScienceHub , Saarbr\u00fccken ,","place":["Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Leidy-Alejandra G","family":"Molano","sequence":"additional","affiliation":[{"name":"Clinical Bioinformatics, Saarland University, Saarbr\u00fccken 66123 ,","place":["Germany"]},{"name":"Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) , Saarland University Campus, Saarbr\u00fccken ,","place":["Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3634-8802","authenticated-orcid":false,"given":"S\u00f6ren L","family":"Becker","sequence":"additional","affiliation":[{"name":"Institute of Medical Microbiology and Hygiene, Saarland University , Kirrberger Stra\u00dfe, Building 43, Homburg 66421 ,","place":["Germany"]},{"name":"Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) , Saarland University Campus, Saarbr\u00fccken ,","place":["Germany"]},{"name":"PharmaScienceHub , Saarbr\u00fccken 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