{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T13:55:51Z","timestamp":1790776551780,"version":"4.1.0"},"reference-count":37,"publisher":"American Society for Microbiology","license":[{"start":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T00:00:00Z","timestamp":1790726400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T00:00:00Z","timestamp":1790726400000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.asm.org\/non-commercial-tdm-license"}],"funder":[{"DOI":"10.13039\/100000060","name":"National Institute of Allergy and Infectious Diseases","doi-asserted-by":"publisher","award":["2R01AI130060"],"award-info":[{"award-number":["2R01AI130060"]}],"id":[{"id":"10.13039\/100000060","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000060","name":"National Institute of Allergy and Infectious Diseases","doi-asserted-by":"publisher","award":["R01AI179046-01A1"],"award-info":[{"award-number":["R01AI179046-01A1"]}],"id":[{"id":"10.13039\/100000060","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["journals.asm.org"],"crossmark-restriction":true},"short-container-title":["J Clin Microbiol"],"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:sec>\n                    <jats:title\/>\n                    <jats:p>\n                      Carbapenem-resistant\n                      <jats:italic toggle=\"yes\">Acinetobacter baumannii<\/jats:italic>\n                      (CRAB) is an extensively drug-resistant pathogen requiring new therapeutic strategies. Rifabutin (RBT), a U.S. Food and Drug Administration (FDA)-approved rifamycin, has demonstrated potent activity against CRAB; however, its activity is systematically underestimated by conventional antimicrobial susceptibility testing (AST) performed in conventional iron-rich Mueller-Hinton media, necessitating methods that accurately predict\n                      <jats:italic toggle=\"yes\">in vivo<\/jats:italic>\n                      efficacy to guide its clinical use. Here, we describe the development of a disk diffusion method for RBT susceptibility testing against\n                      <jats:italic toggle=\"yes\">A. baumannii<\/jats:italic>\n                      . Following Clinical and Laboratory Standards Institute (CLSI) M23 \u201cDevelopment of\n                      <jats:italic toggle=\"yes\">In Vitro<\/jats:italic>\n                      Susceptibility Test Methods, Breakpoints, and Quality Control Parameters\u201d guidance, multiple disk potencies were evaluated across standard and chelated Mueller-Hinton agar (MHA), including EDTA-supplemented media, and zone-of-inhibition (ZOI) diameters were correlated with MICs determined by agar dilution. A 20-\u00b5g RBT disk on chelated MHA, or equivalently on MHA supplemented with 100 mg\/L EDTA, provided clear and reproducible discrimination of tentative wild-type and non-wild-type phenotypes, and preliminary quality control testing supported\n                      <jats:italic toggle=\"yes\">A. baumannii<\/jats:italic>\n                      NCTC 13304 as a candidate quality control strain. While this investigational method has not been reviewed or approved by the CLSI, it was developed in concordance with the M23 guidance and addresses the key limitations of conventional AST, providing a robust framework for interlaboratory validation and future breakpoint determination.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>IMPORTANCE<\/jats:title>\n                    <jats:p>\n                      Antimicrobial susceptibility testing is a critical tool for guiding clinical treatment decisions. Rifabutin exhibits potent activity against carbapenem-resistant\n                      <jats:italic toggle=\"yes\">Acinetobacter baumannii<\/jats:italic>\n                      (CRAB) under the iron-restricted conditions encountered\n                      <jats:italic toggle=\"yes\">in vivo<\/jats:italic>\n                      ; however, its activity is systematically underestimated by standard testing methods in iron-rich Mueller-Hinton media. Here, we describe a robust, simple, and reproducible disk diffusion method using a 20-\u00b5g rifabutin disk on chelated Mueller-Hinton agar, which enables accurate assessment of rifabutin activity against\n                      <jats:italic toggle=\"yes\">A. baumannii<\/jats:italic>\n                      . Our method provides a practical foundation for standardized rifabutin susceptibility testing, future breakpoint development, and broader evaluation of rifabutin against CRAB to ultimately support its implementation in clinical microbiology laboratories.\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.1128\/jcm.00598-26","type":"journal-article","created":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T13:01:48Z","timestamp":1790773308000},"update-policy":"https:\/\/doi.org\/10.1128\/asmj-crossmark-policy-page","source":"Crossref","is-referenced-by-count":0,"title":["Rifabutin disk diffusion on chelated Mueller-Hinton agar: a robust methodological framework for accurate\n                    <i>Acinetobacter baumannii<\/i>\n                    susceptibility testing"],"prefix":"10.1128","author":[{"ORCID":"https:\/\/orcid.org\/0009-0007-3060-5085","authenticated-orcid":true,"given":"Michelle","family":"Zorawik","sequence":"first","affiliation":[{"name":"Department of Immunology and Immune Therapeutics, Keck School of Medicine at USC","place":["Los Angeles, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jordyn","family":"VanOrman","sequence":"additional","affiliation":[{"name":"Department of Immunology and Immune Therapeutics, Keck School of Medicine at USC","place":["Los Angeles, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Luke","family":"Bender","sequence":"additional","affiliation":[{"name":"Department of Immunology and Immune Therapeutics, Keck School of Medicine at USC","place":["Los Angeles, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lauren","family":"Tanner","sequence":"additional","affiliation":[{"name":"Department of Immunology and Immune Therapeutics, Keck School of Medicine at USC","place":["Los Angeles, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8773-1687","authenticated-orcid":true,"given":"Rosemary","family":"She","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/01z1vct10","id-type":"ROR","asserted-by":"publisher"}],"name":"Department of Pathology, City of Hope","place":["Duarte, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3632-1709","authenticated-orcid":true,"given":"Brad","family":"Spellberg","sequence":"additional","affiliation":[{"name":"Los Angeles General Medical Center","place":["Los Angeles, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6718-4551","authenticated-orcid":true,"given":"Brian","family":"Luna","sequence":"additional","affiliation":[{"name":"Department of Immunology and Immune Therapeutics, Keck School of Medicine at USC","place":["Los Angeles, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"235","published-online":{"date-parts":[[2026,9,30]]},"reference":[{"key":"e_1_3_4_2_2","doi-asserted-by":"publisher","DOI":"10.1038\/nrmicro1789"},{"key":"e_1_3_4_3_2","unstructured":"Centers for Disease Control and Prevention (U.S.). 2019. Antibiotic resistance threats in the United States. Available from: https:\/\/stacks.cdc.gov\/view\/cdc\/82532"},{"key":"e_1_3_4_4_2","unstructured":"WHO bacterial priority pathogens list 2024: bacterial pathogens of public health importance to guide research development and strategies to prevent and control antimicrobial resistance. 2024. World Health Organization Geneva"},{"key":"e_1_3_4_5_2","doi-asserted-by":"publisher","DOI":"10.1038\/s41564-020-0737-6"},{"key":"e_1_3_4_6_2","doi-asserted-by":"publisher","DOI":"10.1093\/jac\/dkaa370"},{"key":"e_1_3_4_7_2","doi-asserted-by":"publisher","DOI":"10.1128\/msphere.00920-21"},{"key":"e_1_3_4_8_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.drudis.2021.07.001"},{"key":"e_1_3_4_9_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.ebiom.2017.07.002"},{"key":"e_1_3_4_10_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.ebiom.2017.05.026"},{"key":"e_1_3_4_11_2","volume-title":"CLSI supplement M100","author":"Clinical and Laboratory Standards Institute (CLSI)","year":"2024","unstructured":"Clinical and Laboratory Standards Institute (CLSI). 2024. Performance standards for antimicrobial susceptibility testing. In CLSI supplement M100, 34th ed","edition":"34"},{"key":"e_1_3_4_12_2","doi-asserted-by":"publisher","DOI":"10.1093\/jac\/dkg312"},{"key":"e_1_3_4_13_2","doi-asserted-by":"publisher","DOI":"10.7759\/cureus.36977"},{"key":"e_1_3_4_14_2","volume-title":"M07 Ed12","author":"CLSI","year":"2024","unstructured":"CLSI. 2024. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically. In M07 Ed12, 12th ed. Clinical & Laboratory Standards Institute.","edition":"12"},{"key":"e_1_3_4_15_2","unstructured":"CLSI. 2025. AST meeting agenda summary minutes. https:\/\/clsi.org\/media\/htnpmsvc\/2025_january_ast_meeting_agenda_summary_minutes.pdf."},{"key":"e_1_3_4_16_2","doi-asserted-by":"publisher","DOI":"10.1201\/9781420014495-11"},{"key":"e_1_3_4_17_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.heliyon.2024.e37116"},{"key":"e_1_3_4_18_2","doi-asserted-by":"publisher","DOI":"10.1128\/JCM.00437-18"},{"key":"e_1_3_4_19_2","volume-title":"Development of in vitro susceptibility test methods, breakpoints, and quality control parameters","author":"CLSI","year":"2023","unstructured":"CLSI. 2023. M23 Ed6E. In Development of in vitro susceptibility test methods, breakpoints, and quality control parameters, 6th ed. Clinical & Laboratory Standards Institute.","edition":"6"},{"key":"e_1_3_4_20_2","volume-title":"Procedure for optimizing disk contents (potencies) for disk diffusion testing of antimicrobial agents using harmonized CLSI and EUCAST criteria","author":"CLSI","year":"2020","unstructured":"CLSI. 2020. M23 Ed6SEd2E. In Procedure for optimizing disk contents (potencies) for disk diffusion testing of antimicrobial agents using harmonized CLSI and EUCAST criteria, 2nd ed. Clinical & Laboratory Standards Institute.","edition":"2"},{"key":"e_1_3_4_21_2","volume-title":"Performance standards for antimicrobial disk susceptibility tests","author":"CLSI","year":"2024","unstructured":"CLSI. 2024. M02 Ed14. In Performance standards for antimicrobial disk susceptibility tests, 14th ed. Clinical & Laboratory Standards Institute.","edition":"14"},{"key":"e_1_3_4_22_2","doi-asserted-by":"publisher","DOI":"10.3791\/51456"},{"key":"e_1_3_4_23_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.01457-06"},{"key":"e_1_3_4_24_2","doi-asserted-by":"publisher","DOI":"10.1128\/JCM.00951-20"},{"key":"e_1_3_4_25_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.ijantimicag.2024.107193"},{"key":"e_1_3_4_26_2","volume-title":"Ethylenediaminetetraacetic acid (EDTA)","author":"George T","year":"2025","unstructured":"George T, Brady MF. 2025. Ethylenediaminetetraacetic acid (EDTA). StatPearls, Treasure Island (FL)."},{"key":"e_1_3_4_27_2","doi-asserted-by":"publisher","DOI":"10.1093\/ofid\/ofaa460"},{"key":"e_1_3_4_28_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.02204-20"},{"key":"e_1_3_4_29_2","doi-asserted-by":"publisher","DOI":"10.1093\/cid\/cit253"},{"key":"e_1_3_4_30_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1469-0691.2006.01377.x"},{"key":"e_1_3_4_31_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1574-6968.1988.tb02907.x"},{"key":"e_1_3_4_32_2","doi-asserted-by":"publisher","DOI":"10.1128\/JCM.00966-20"},{"key":"e_1_3_4_33_2","doi-asserted-by":"publisher","DOI":"10.1093\/jac\/dkac080"},{"key":"e_1_3_4_34_2","doi-asserted-by":"publisher","DOI":"10.1093\/jalm\/jfac131"},{"key":"e_1_3_4_35_2","doi-asserted-by":"publisher","DOI":"10.1128\/jcm.01648-24"},{"key":"e_1_3_4_36_2","doi-asserted-by":"publisher","DOI":"10.1128\/mr.56.3.395-411.1992"},{"key":"e_1_3_4_37_2","doi-asserted-by":"publisher","DOI":"10.1128\/AEM.72.3.2064-2069.2006"},{"key":"e_1_3_4_38_2","doi-asserted-by":"publisher","DOI":"10.3390\/biom8040122"}],"container-title":["Journal of Clinical Microbiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.asm.org\/doi\/pdf\/10.1128\/jcm.00598-26","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.asm.org\/doi\/pdf\/10.1128\/jcm.00598-26","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T13:01:52Z","timestamp":1790773312000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.asm.org\/doi\/10.1128\/jcm.00598-26"}},"subtitle":[],"editor":[{"given":"Patricia J.","family":"Simner","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"editor"}]}],"short-title":[],"issued":{"date-parts":[[2026,9,30]]},"references-count":37,"alternative-id":["10.1128\/jcm.00598-26"],"URL":"https:\/\/doi.org\/10.1128\/jcm.00598-26","relation":{},"ISSN":["0095-1137","1098-660X"],"issn-type":[{"value":"0095-1137","type":"print"},{"value":"1098-660X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,30]]},"assertion":[{"value":"2026-04-20","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-08-30","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-09-30","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"e00598-26"}}