{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,1]],"date-time":"2026-06-01T18:56:28Z","timestamp":1780340188797,"version":"3.54.1"},"reference-count":29,"publisher":"American Society for Microbiology","issue":"3","license":[{"start":{"date-parts":[[2025,3,5]],"date-time":"2025-03-05T00:00:00Z","timestamp":1741132800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2025,3,5]],"date-time":"2025-03-05T00:00:00Z","timestamp":1741132800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.asm.org\/non-commercial-tdm-license"}],"content-domain":{"domain":["journals.asm.org"],"crossmark-restriction":true},"short-container-title":["Antimicrob Agents Chemother"],"published-print":{"date-parts":[[2025,3,5]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n          <jats:sec>\n            <jats:title\/>\n            <jats:p>\n              The combination of aztreonam and ceftazidime\u2013avibactam (ATM\u2013CZA) is a last resort regimen against recalcitrant infections caused by metallo-\u03b2-lactamase (MBL)-producing organisms. Susceptibility testing is warranted due to emerging resistance to the combination, but there are no widely implemented methods for use in clinical laboratories. Here, we used a cohort of 100 Enterobacterales\n              <jats:italic>, Pseudomonas aeruginosa<\/jats:italic>\n              , and\n              <jats:italic>Stenotrophomonas maltophilia<\/jats:italic>\n              strains, including 68 MBL producers, to evaluate the performance of two ETEST strip-based synergy testing methods: the side-by-side (SS) method with an ATM ETEST placed next to a CZA ETEST (10 mm apart) and the strip cross (SX) method with a CZA ETEST placed perpendicularly on top of the ATM ETEST (at the 8 \u00b5g\/mL mark). By reference broth microdilution (BMD), 89.1% (41\/46) of the Enterobacterales, 15% (3\/20) of the\n              <jats:italic>P. aeruginosa<\/jats:italic>\n              , and 97.1% (33\/34) of the\n              <jats:italic>S. maltophilia<\/jats:italic>\n              isolates tested susceptible to the ATM\u2013CZA combination. The SS method yielded 72% categorical agreement with BMD and 28 major errors (ME, 36.4%). Initial testing with the SX method yielded three ME , of which one was resolved upon repeat testing, yielding a final categorical agreement of 98% with BMD with two ME (2.6%). The SX method also yielded 100% reproducibility across three brands of Mueller Hinton agar (BD, Hardy, Remel). Our study demonstrates that the SX method is accurate, precise, and feasible for clinical laboratories to perform ATM\u2013CZA susceptibility testing to guide use of the combination for treatment of multidrug-resistant gram-negative pathogens.\n            <\/jats:p>\n          <\/jats:sec>","DOI":"10.1128\/aac.01736-24","type":"journal-article","created":{"date-parts":[[2025,2,7]],"date-time":"2025-02-07T14:00:45Z","timestamp":1738936845000},"update-policy":"https:\/\/doi.org\/10.1128\/asmj-crossmark-policy-page","source":"Crossref","is-referenced-by-count":10,"title":["Evaluation of two gradient diffusion tests to determine susceptibility to aztreonam and ceftazidime\u2013avibactam in combination"],"prefix":"10.1128","volume":"69","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0489-0712","authenticated-orcid":true,"given":"Ayesha","family":"Khan","sequence":"first","affiliation":[{"name":"Pathology, Microbiology and Immunology, Vanderbilt University Medical Center","place":["Nashville, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Carmila","family":"Manuel","sequence":"additional","affiliation":[{"name":"Pathology, Microbiology and Immunology, Vanderbilt University Medical Center","place":["Nashville, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Richard","family":"Maynard","sequence":"additional","affiliation":[{"name":"Pathology, Microbiology and Immunology, Vanderbilt University Medical Center","place":["Nashville, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6568-156X","authenticated-orcid":true,"given":"Romney M.","family":"Humphries","sequence":"additional","affiliation":[{"name":"Pathology, Microbiology and Immunology, Vanderbilt University Medical Center","place":["Nashville, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"235","reference":[{"key":"e_1_3_1_2_2","doi-asserted-by":"publisher","DOI":"10.1093\/cid\/ciz830"},{"key":"e_1_3_1_3_2","doi-asserted-by":"publisher","DOI":"10.1186\/s12879-019-4409-1"},{"key":"e_1_3_1_4_2","doi-asserted-by":"publisher","DOI":"10.1093\/jac\/dkad280"},{"key":"e_1_3_1_5_2","doi-asserted-by":"publisher","DOI":"10.1093\/cid\/ciz530"},{"key":"e_1_3_1_6_2","doi-asserted-by":"publisher","DOI":"10.1001\/jama.2018.0438"},{"key":"e_1_3_1_7_2","doi-asserted-by":"publisher","DOI":"10.1093\/cid\/cix783"},{"key":"e_1_3_1_8_2","doi-asserted-by":"publisher","DOI":"10.1007\/s40121-018-0214-1"},{"key":"e_1_3_1_9_2","doi-asserted-by":"publisher","DOI":"10.1093\/ofid\/ofaa051"},{"key":"e_1_3_1_10_2","doi-asserted-by":"publisher","DOI":"10.1093\/ofid\/ofaa051"},{"key":"e_1_3_1_11_2","doi-asserted-by":"publisher","DOI":"10.1093\/ofid\/ofad046"},{"key":"e_1_3_1_12_2","doi-asserted-by":"publisher","DOI":"10.1016\/S2666-5247(22)00329-9"},{"key":"e_1_3_1_13_2","doi-asserted-by":"publisher","DOI":"10.1093\/cid\/ciad100"},{"key":"e_1_3_1_14_2","doi-asserted-by":"publisher","DOI":"10.1093\/ofid\/ofaa141"},{"key":"e_1_3_1_15_2","doi-asserted-by":"publisher","DOI":"10.1093\/cid\/ciad428"},{"key":"e_1_3_1_16_2","doi-asserted-by":"publisher","DOI":"10.1093\/cid\/ciaa586"},{"key":"e_1_3_1_17_2","doi-asserted-by":"publisher","DOI":"10.1007\/s41669-022-00368-w"},{"key":"e_1_3_1_18_2","unstructured":"The Health Insurance Review and Assessment Service (President Kang Jung-Gu). 2024. Publication of review result of the tenth pharmaceutical reimbursement evaluation committee Of2023. Korea"},{"key":"e_1_3_1_19_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.01659-20"},{"key":"e_1_3_1_20_2","article-title":"Aztreonam\/avibactam activity against a large collection of carbapenem-resistant enterobacterales (CRE) collected in hospitals from Europe","volume":"5","author":"Sader HS","year":"2023","unstructured":"Sader HS, Castanheira M, Kimbrough JH, Kantro V, Mendes RE. 2023. Aztreonam\/avibactam activity against a large collection of carbapenem-resistant enterobacterales (CRE) collected in hospitals from Europe. Asia and Latin America JAC Antimicrob Resist 5:dlad032.","journal-title":"Asia and Latin America"},{"key":"e_1_3_1_21_2","doi-asserted-by":"publisher","DOI":"10.1093\/pcmedi\/pbac029"},{"key":"e_1_3_1_22_2","doi-asserted-by":"publisher","DOI":"10.1093\/jac\/dkab279"},{"key":"e_1_3_1_23_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.00846-21"},{"key":"e_1_3_1_24_2","doi-asserted-by":"publisher","DOI":"10.1128\/jcm.01647-22"},{"key":"e_1_3_1_25_2","volume-title":"Development of In Vitro Susceptibility Test Methods, Breakpoints, and Quality Control Parameters","author":"Clinical Laboratory and Standards Institute","year":"2023","unstructured":"Clinical Laboratory and Standards Institute. 2023. Development of In Vitro Susceptibility Test Methods, Breakpoints, and Quality Control Parameters. 6th ed","edition":"6"},{"key":"e_1_3_1_26_2","doi-asserted-by":"publisher","DOI":"10.1093\/ofid\/ofz273"},{"key":"e_1_3_1_27_2","volume-title":"CLSI M07 Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria That Grow Aerobically","author":"Clinical laboratory and standards institute","year":"2024","unstructured":"Clinical laboratory and standards institute. 2024. CLSI M07 Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria That Grow Aerobically. 12th ed","edition":"12"},{"key":"e_1_3_1_28_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.00472-17"},{"key":"e_1_3_1_29_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.01433-20"},{"key":"e_1_3_1_30_2","volume-title":"Performance standards for 520 antimicrobial susceptibility testing","author":"Clinical laboratory and standards institute","year":"2024","unstructured":"Clinical laboratory and standards institute. 2024. Performance standards for 520 antimicrobial susceptibility testing. 34th ed","edition":"34"}],"container-title":["Antimicrobial Agents and Chemotherapy"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.asm.org\/doi\/pdf\/10.1128\/aac.01736-24","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.asm.org\/doi\/pdf\/10.1128\/aac.01736-24","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,4,4]],"date-time":"2025-04-04T05:12:26Z","timestamp":1743743546000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.asm.org\/doi\/10.1128\/aac.01736-24"}},"subtitle":[],"editor":[{"given":"Pranita D.","family":"Tamma","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"editor"}]}],"short-title":[],"issued":{"date-parts":[[2025,3,5]]},"references-count":29,"journal-issue":{"issue":"3","published-print":{"date-parts":[[2025,3,5]]}},"alternative-id":["10.1128\/aac.01736-24"],"URL":"https:\/\/doi.org\/10.1128\/aac.01736-24","relation":{},"ISSN":["0066-4804","1098-6596"],"issn-type":[{"value":"0066-4804","type":"print"},{"value":"1098-6596","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,3,5]]},"assertion":[{"value":"2024-11-19","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-01-12","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-02-07","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"e01736-24"}}