{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T15:38:37Z","timestamp":1785425917983,"version":"3.56.0"},"reference-count":34,"publisher":"American Society for Microbiology","issue":"10","license":[{"start":{"date-parts":[[2025,10,7]],"date-time":"2025-10-07T00:00:00Z","timestamp":1759795200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2025,10,7]],"date-time":"2025-10-07T00:00:00Z","timestamp":1759795200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.asm.org\/non-commercial-tdm-license"}],"funder":[{"DOI":"10.13039\/501100003710","name":"Korea Health Industry Development Institute","doi-asserted-by":"publisher","award":["RS-2024-00332244"],"award-info":[{"award-number":["RS-2024-00332244"]}],"id":[{"id":"10.13039\/501100003710","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["journals.asm.org"],"crossmark-restriction":true},"short-container-title":["Microbiol Spectr"],"published-print":{"date-parts":[[2025,10,7]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:sec>\n                    <jats:title\/>\n                    <jats:p>\n                      We assessed the performance of the VITEK 2 AST-N439 card for susceptibility testing of novel \u03b2-lactam\/\u03b2-lactamase inhibitor (BL\/BLI) combinations and colistin in carbapenem-non-susceptible gram-negative isolates. A total of 425 clinical isolates, including\n                      <jats:italic toggle=\"yes\">Enterobacterales<\/jats:italic>\n                      (\n                      <jats:italic toggle=\"yes\">n<\/jats:italic>\n                      = 242),\n                      <jats:italic toggle=\"yes\">Pseudomonas aeruginosa<\/jats:italic>\n                      (\n                      <jats:italic toggle=\"yes\">n<\/jats:italic>\n                      = 97), and\n                      <jats:italic toggle=\"yes\">Acinetobacter baumannii<\/jats:italic>\n                      (\n                      <jats:italic toggle=\"yes\">n<\/jats:italic>\n                      = 86), were tested using VITEK 2, with broth microdilution as the reference standard. Minimum inhibitory concentrations were interpreted according to Clinical and Laboratory Standards Institute breakpoints. The essential agreement (EA), categorical agreement (CA), very major error rate, and major error rate for VITEK 2 were 90.3%, 97.6%, 1.8%, and 2.5% for ceftazidime\/avibactam; 81.5%, 89.0%, 7.0%, and 4.7% for ceftolozane\/tazobactam; 96.5%, 90.9%, 3.4%, and 1.2% for imipenem\/relebactam; and 94.6%, 93.0%, 15.8%, and 3.2% for meropenem\/vaborbactam. For colistin, VITEK 2 demonstrated an EA of 89.2% and a CA of 85.4%. Our findings suggest that VITEK 2 has suboptimal performance for novel BL\/BLI combinations in carbapenem-non-susceptible gram-negative isolates. Furthermore, despite changes to the colistin formulation used in the VITEK 2 card, it remains an unreliable method for detecting colistin resistance.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>IMPORTANCE<\/jats:title>\n                    <jats:p>Rapid and accurate antimicrobial susceptibility testing (AST) is essential for managing infections caused by multidrug-resistant gram-negative bacilli. This study evaluated the performance of the VITEK 2 AST-N439 card for susceptibility testing of novel BL\/BLI combinations and colistin in carbapenem-non-susceptible gram-negative isolates. Our findings revealed significant limitations, including suboptimal performance for novel BL\/BLI combinations and unreliable detection of colistin resistance, even with the updated formulation. These results underscore the need for cautious interpretation of VITEK 2 results and highlight the importance of optimizing its performance to enhance antibiotic decision-making.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1128\/spectrum.00166-25","type":"journal-article","created":{"date-parts":[[2025,8,21]],"date-time":"2025-08-21T18:36:06Z","timestamp":1755801366000},"update-policy":"https:\/\/doi.org\/10.1128\/asmj-crossmark-policy-page","source":"Crossref","is-referenced-by-count":6,"title":["Evaluation of the VITEK 2 AST-N439 card for susceptibility testing of novel \u03b2-lactam\/\u03b2-lactamase inhibitor combinations and colistin in carbapenem-non-susceptible gram-negative bacilli"],"prefix":"10.1128","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6405-5305","authenticated-orcid":true,"given":"Tae Yeul","family":"Kim","sequence":"first","affiliation":[{"id":[{"id":"https:\/\/ror.org\/04q78tk20","id-type":"ROR","asserted-by":"publisher"}],"name":"Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine","place":["Seoul, Republic of Korea"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jin Yang","family":"Baek","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/01gaag595","id-type":"ROR","asserted-by":"publisher"}],"name":"Asia Pacific Foundation for Infectious Diseases (APFID)","place":["Seoul, Republic of Korea"]},{"id":[{"id":"https:\/\/ror.org\/04q78tk20","id-type":"ROR","asserted-by":"publisher"}],"name":"Division of Infectious Diseases, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine","place":["Seoul, Republic of 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Laboratory Medicine, Seoul Medical Center","place":["Seoul, Republic of Korea"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9490-6609","authenticated-orcid":true,"given":"Jae-Hoon","family":"Ko","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/04q78tk20","id-type":"ROR","asserted-by":"publisher"}],"name":"Division of Infectious Diseases, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine","place":["Seoul, Republic of Korea"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8999-7561","authenticated-orcid":true,"given":"Hee Jae","family":"Huh","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/04q78tk20","id-type":"ROR","asserted-by":"publisher"}],"name":"Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine","place":["Seoul, Republic of 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Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically, p M07\u2013A10. Clinical and Laboratory Standards Institute, Wayne, PA."},{"key":"e_1_3_4_19_2","series-title":"CLSI Supplement M100","volume-title":"Performance standards for antimicrobial susceptibility testing","author":"CLSI","year":"2024","unstructured":"CLSI. 2024. Performance standards for antimicrobial susceptibility testing. 34th ed. CLSI Supplement M100. Clinical and Laboratory Standards Institute, Wayne, PA.","edition":"34"},{"key":"e_1_3_4_20_2","unstructured":"ISO. 2007. Clinical laboratory testing and in vitro diagnostic test systems\u2014 susceptibility testing of infectious agents and evaluation of performance of antimicrobial susceptibility test devices\u2014part 2: evaluation of performance of antimicrobial susceptibility test devices. 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