{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,13]],"date-time":"2026-10-13T00:43:35Z","timestamp":1791852215966,"version":"4.3.4"},"reference-count":20,"publisher":"American Society for Microbiology","issue":"5","license":[{"start":{"date-parts":[[2026,5,13]],"date-time":"2026-05-13T00:00:00Z","timestamp":1778630400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,5,13]],"date-time":"2026-05-13T00:00:00Z","timestamp":1778630400000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.asm.org\/non-commercial-tdm-license"}],"funder":[{"DOI":"10.13039\/501100022110","name":"bioM\u00e9rieux","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100022110","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["journals.asm.org"],"crossmark-restriction":true},"short-container-title":["J Clin Microbiol"],"published-print":{"date-parts":[[2026,5,13]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:sec>\n                    <jats:title\/>\n                    <jats:p>\n                      Aztreonam-avibactam (AZA) is a new monobactam\/beta-lactamase inhibitor combination that recently received regulatory approval in the United States (U.S.) and Europe. In this study, we evaluated the performance of ETEST AZA, a gradient diffusion method, compared to reference broth microdilution for 650 challenge (\n                      <jats:italic toggle=\"yes\">n<\/jats:italic>\n                      = 77) and clinical (\n                      <jats:italic toggle=\"yes\">n<\/jats:italic>\n                      = 573)\n                      <jats:italic toggle=\"yes\">Enterobacterales<\/jats:italic>\n                      isolates across four study sites. Using the U.S. Food and Drug Administration (FDA) interpretive breakpoints for ETEST AZA, challenge isolates demonstrated a 97.3% (72\/74) essential agreement (EA), 93.2% (69\/74) categorical agreement (CA), 0% very major errors (VME) and major errors (ME), and 6.8% (5\/74) minor errors (mE). Clinical isolates demonstrated a 95.5% (504\/528) EA, 98.7% (521\/528) CA, 0% VME, 0.2% (1\/516) ME, and 1.1% (6\/528) mE. Overall, the combined set achieved a 95.7% (576\/602) EA and 98.0% (590\/602) CA, with 0% VME, 0.2% (1\/577) ME, and 1.8% (11\/602) mE. Using the European Committee on Antimicrobial Susceptibility Testing (EUCAST) interpretive breakpoints, challenge isolates demonstrated a 96.1% (74\/77) EA, 93.5% (72\/77) CA, and 31.3% (5\/16) VMEs, while clinical isolates demonstrated a 94.1% (539\/573) EA and 99.7% (571\/573) CA including 7.7% (1\/13) VME and 0.2% (1\/560) ME. The combined set demonstrated a 94.3% (613\/650) EA, 98.9% (643\/650) CA, 0.2% (1\/573) MEs, but 20.7% (6\/21) VMEs due to the lack of an intermediate breakpoint that is addressed as a limitation in the European package insert. Both bias and trending were in alignment with regulatory requirements. In reproducibility testing of 10 on-scale strains, 100% (270\/270) of the results were within \u00b11 doubling dilution of the modal minimal inhibitory concentration. In conclusion, ETEST AZA provides accurate, reproducible susceptibility results that meet regulatory requirements for many\n                      <jats:italic toggle=\"yes\">Enterobacterales<\/jats:italic>\n                      species when interpreted using FDA or EUCAST criteria.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>IMPORTANCE<\/jats:title>\n                    <jats:p>\n                      Aztreonam-avibactam (AZA) is a novel monobactam\/\u03b2-lactamase inhibitor combination approved for clinical use in the United States and Europe in 2025 and 2024, respectively. It is indicated for the treatment of multidrug-resistant Gram-negative bacteria that produce multiple classes of \u03b2-lactamases. Until recently, antimicrobial susceptibility testing for this combined agent relied on broth disk elution or microdilution using ceftazidime\u2013avibactam and aztreonam combined. In this study, we evaluated the performance of the bioM\u00e9rieux ETEST AZA gradient diffusion strip as a more streamlined method for clinical microbiology laboratories. Testing of 650\n                      <jats:italic toggle=\"yes\">Enterobacterales<\/jats:italic>\n                      isolates demonstrated that ETEST AZA met regulatory performance criteria using interpretive breakpoints from both the FDA and the European Committee on Antimicrobial Susceptibility Testing. Overall, our findings indicate that the ETEST AZA demonstrates acceptable performance for many\n                      <jats:italic toggle=\"yes\">Enterobacterales<\/jats:italic>\n                      isolates and represents a practical alternative for implementing AZA susceptibility testing in clinical microbiology laboratories.\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.1128\/jcm.01749-25","type":"journal-article","created":{"date-parts":[[2026,4,20]],"date-time":"2026-04-20T13:40:39Z","timestamp":1776692439000},"update-policy":"https:\/\/doi.org\/10.1128\/asmj-crossmark-policy-page","source":"Crossref","is-referenced-by-count":4,"title":["A multicenter performance evaluation of aztreonam-avibactam gradient diffusion susceptibility testing for\n                    <i>Enterobacterales<\/i>"],"prefix":"10.1128","volume":"64","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4110-3263","authenticated-orcid":true,"given":"Tina I.","family":"Bui","sequence":"first","affiliation":[{"name":"Department of Pathology and Immunology, Washington University School of Medicine","place":["Saint Louis, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0001-8910-9648","authenticated-orcid":true,"given":"Edith","family":"Csiki-Fejer","sequence":"additional","affiliation":[{"name":"bioM\u00e9rieux Clinical Affairs","place":["Saint Louis, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sarah","family":"Prudhomme","sequence":"additional","affiliation":[{"name":"bioM\u00e9rieux Clinical Affairs","place":["Marcy-l\u2019Etoile, France"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Louise","family":"Bossy","sequence":"additional","affiliation":[{"name":"bioM\u00e9rieux Clinical Affairs","place":["Marcy-l\u2019Etoile, France"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dwight J.","family":"Hardy","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/00trqv719","id-type":"ROR","asserted-by":"publisher"}],"name":"Department of Microbiology and Immunology, University of Rochester Medical Center","place":["Rochester, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2227-3355","authenticated-orcid":true,"given":"Mandy","family":"Wootton","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/04fgpet95","id-type":"ROR","asserted-by":"publisher"}],"name":"Public Health Wales Microbiology, University Hospital of Wales","place":["Cardiff, United Kingdom"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gilles","family":"Zambardi","sequence":"additional","affiliation":[{"name":"bioM\u00e9rieux Clinical Affairs","place":["Marcy-l\u2019Etoile, France"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2166-7552","authenticated-orcid":true,"given":"Melanie L.","family":"Yarbrough","sequence":"additional","affiliation":[{"name":"Department of Pathology and Immunology, Washington University School of Medicine","place":["Saint Louis, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"235","reference":[{"key":"e_1_3_2_2_2","doi-asserted-by":"publisher","DOI":"10.1093\/cid\/ciae403"},{"key":"e_1_3_2_3_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.00774-09"},{"key":"e_1_3_2_4_2","doi-asserted-by":"publisher","DOI":"10.1093\/ofid\/ofaf250"},{"key":"e_1_3_2_5_2","doi-asserted-by":"publisher","DOI":"10.1128\/jcm.01647-22"},{"key":"e_1_3_2_6_2","volume-title":"M100: performance standards for antimicrobial susceptibility testing","author":"Clinical and Laboratory Standards Institute","year":"2025","unstructured":"Clinical and Laboratory Standards Institute. 2025. M100: performance standards for antimicrobial susceptibility testing. 35th ed. CLSI, Wayne, PA.","edition":"35"},{"key":"e_1_3_2_7_2","volume-title":"M100: performance standards for antimicrobial susceptibility testing","author":"Clinical and Laboratory Standards Institute","year":"2023","unstructured":"Clinical and Laboratory Standards Institute. 2023. M100: performance standards for antimicrobial susceptibility testing. 33rd ed. CLSI, Wayne, PA.","edition":"33"},{"key":"e_1_3_2_8_2","unstructured":"bioM\u00e9rieux. 2025. ETEST AZA [510(k) Premarket Notification K250856]. Silver Spring MD Food and Drug Administration. https:\/\/www.accessdata.fda.gov\/scripts\/cdrh\/cfdocs\/cfpmn\/pmn.cfm?ID=K250856."},{"key":"e_1_3_2_9_2","volume-title":"M07: methods for dilution antimicrobial susceptibility tests for bactera that grow aerobically","author":"Clinical and Laboratory Standards Institute","year":"2018","unstructured":"Clinical and Laboratory Standards Institute. 2018. M07: methods for dilution antimicrobial susceptibility tests for bactera that grow aerobically. 11th ed. CLSI, Wayne, PA.","edition":"11"},{"key":"e_1_3_2_10_2","unstructured":"European Committee on Antimicrobial Susceptibility Testing. 2025. Breakpoint tables for interpretation of MICs and zone diameters. European Committee on Antimicrobial Susceptibility Testing"},{"key":"e_1_3_2_11_2","unstructured":"US Food and Drug Administration. 2025. US FDA antibacterial susceptibility test interpretive criteria: aztreonam and avibactam injection."},{"key":"e_1_3_2_12_2","unstructured":"Food and Drug Administration (FDA). 2009. Guidance for industry and FDA: class II special controls guidance document: antimicrobial susceptibility test (AST) systems. FDA."},{"key":"e_1_3_2_13_2","unstructured":"International Standards Organization (ISO). 2021. ISO 20776-2:2021: clinical laboratory testing and in vitro diagnostic test systems \u2014 Susceptibility testing of infectious agents and evaluation of performance of antimicrobial susceptibility test devices \u2014 Part 2: evaluation of performance of antimicrobial susceptibility test devices against reference broth micro-dilution. ISO. https:\/\/www.iso.org\/standard\/79377.html."},{"key":"e_1_3_2_14_2","unstructured":"bioM\u00e9rieux. 2025. FDA Package Insert: ETEST Aztreonam\/Avibactam (AZA) (0.016\/4-256\/4 \u03bcg\/mL REF: 424459)"},{"key":"e_1_3_2_15_2","unstructured":"bioM\u00e9rieux. 2025. WW CE Marked: ETEST Aztreonam\/Avibactam (AZA) (0.016\/4-256\/4 \u03bcg\/mL REF: 424460)"},{"key":"e_1_3_2_16_2","doi-asserted-by":"publisher","DOI":"10.1128\/jcm.00649-24"},{"key":"e_1_3_2_17_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.ijantimicag.2024.107256"},{"key":"e_1_3_2_18_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.01090-21"},{"key":"e_1_3_2_19_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.ijantimicag.2023.106776"},{"key":"e_1_3_2_20_2","doi-asserted-by":"publisher","DOI":"10.1093\/jacamr\/dlab092"},{"key":"e_1_3_2_21_2","volume-title":"M100: performance standards for antimicrobial susceptibility testing","author":"Clinical and Laboratory Standards Institute","year":"2026","unstructured":"Clinical and Laboratory Standards Institute. 2026. M100: performance standards for antimicrobial susceptibility testing. 36th ed. CLSI, Wayne, PA.","edition":"36"}],"container-title":["Journal of Clinical Microbiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.asm.org\/doi\/pdf\/10.1128\/jcm.01749-25","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.asm.org\/doi\/pdf\/10.1128\/jcm.01749-25","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,28]],"date-time":"2026-05-28T13:01:28Z","timestamp":1779973288000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.asm.org\/doi\/10.1128\/jcm.01749-25"}},"subtitle":[],"editor":[{"given":"Erin","family":"McElvania","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"editor"}]}],"short-title":[],"issued":{"date-parts":[[2026,5,13]]},"references-count":20,"journal-issue":{"issue":"5","published-print":{"date-parts":[[2026,5,13]]}},"alternative-id":["10.1128\/jcm.01749-25"],"URL":"https:\/\/doi.org\/10.1128\/jcm.01749-25","relation":{},"ISSN":["0095-1137","1098-660X"],"issn-type":[{"value":"0095-1137","type":"print"},{"value":"1098-660X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,5,13]]},"assertion":[{"value":"2025-11-25","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-03-10","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-04-20","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"e01749-25"}}