{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,27]],"date-time":"2026-10-27T20:28:32Z","timestamp":1793132912079,"version":"4.5.0"},"reference-count":26,"publisher":"American Society for Microbiology","issue":"7","license":[{"start":{"date-parts":[[2026,7,8]],"date-time":"2026-07-08T00:00:00Z","timestamp":1783468800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,7,8]],"date-time":"2026-07-08T00:00:00Z","timestamp":1783468800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.asm.org\/non-commercial-tdm-license"}],"funder":[{"DOI":"10.13039\/100005825","name":"National Institute of Food and Agriculture","doi-asserted-by":"publisher","award":["7007417"],"award-info":[{"award-number":["7007417"]}],"id":[{"id":"10.13039\/100005825","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":[[2026,7,8]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:sec>\n                    <jats:title\/>\n                    <jats:p>\n                      <jats:italic toggle=\"yes\">Staphylococcus pseudintermedius<\/jats:italic>\n                      is an important pathogen in companion animals. Accurate detection and reporting of\n                      <jats:italic toggle=\"yes\">mecA<\/jats:italic>\n                      -mediated resistance to \u03b2-lactam antimicrobials is essential for guiding appropriate antimicrobial treatments. While surrogate agents are used in human diagnostic laboratories to predict \u03b2-lactam results in staphylococci, individual \u03b2-lactam breakpoints are published for veterinary staphylococci, discouraging the use of a surrogate. Comparative performance of these individual \u03b2-lactam breakpoints to predict methicillin-resistance in veterinary\n                      <jats:italic toggle=\"yes\">Staphylococcus<\/jats:italic>\n                      species has not been previously evaluated. This study evaluated oxacillin\u2019s accuracy at detecting\n                      <jats:italic toggle=\"yes\">mecA<\/jats:italic>\n                      presence and performance as a surrogate for \u03b2-lactams in\n                      <jats:italic toggle=\"yes\">S. pseudintermedius<\/jats:italic>\n                      from canids and felids. Antimicrobial susceptibility data for\n                      <jats:italic toggle=\"yes\">S. pseudintermedius<\/jats:italic>\n                      were obtained from clinical isolates (\n                      <jats:italic toggle=\"yes\">n<\/jats:italic>\n                      = 1,914) from veterinary diagnostic laboratories across the United States and Canada and included broth microdilution results for amoxicillin-clavulanate, cefazolin, cefovecin, cefpodoxime, cephalothin, and oxacillin, along with the corresponding presence or absence of\n                      <jats:italic toggle=\"yes\">mecA<\/jats:italic>\n                      . Agreement analysis, sensitivities, and specificities were calculated to compare oxacillin performance with individual \u03b2-lactams. Oxacillin demonstrated the highest sensitivity for the prediction of\n                      <jats:italic toggle=\"yes\">mecA<\/jats:italic>\n                      -mediated resistance among all antimicrobials analyzed. For isolates possessing\n                      <jats:italic toggle=\"yes\">mecA<\/jats:italic>\n                      , the proportion showing resistant minimum inhibitory concentrations to \u03b2-lactams other than oxacillin was low, ranging between 16.5% and 85%. Additionally, when compared to oxacillin, all \u03b2-lactams other than cefovecin exhibited high rates of very major discrepancies, corroborating the significant risk of reporting false susceptibility when testing these antimicrobials. These findings support utilizing oxacillin as a surrogate agent for predicting \u03b2-lactam interpretations and emphasize the necessity for clarified guidance in the Clinical Laboratory Standards Institute VET01S document.\n                    <\/jats:p>\n                    <jats:sec>\n                      <jats:title>IMPORTANCE<\/jats:title>\n                      <jats:p>\n                        Accurate testing and reporting of \u03b2-lactam antimicrobials in\n                        <jats:italic toggle=\"yes\">Staphylococcus<\/jats:italic>\n                        species are essential for guiding appropriate antimicrobial therapy in companion animals. Our findings show that oxacillin is the most sensitive antimicrobial for detecting\n                        <jats:italic toggle=\"yes\">mecA<\/jats:italic>\n                        -mediated resistance when testing\n                        <jats:italic toggle=\"yes\">Staphylococcus pseudintermedius<\/jats:italic>\n                        , while most other \u03b2-lactams have low sensitivity for\n                        <jats:italic toggle=\"yes\">mecA<\/jats:italic>\n                        and unacceptable rates of very major discrepancies when compared to oxacillin. These results highlight the risk of reporting falsely reporting \u03b2-lactam results when interpretations are based solely on testing each individual agent. Therefore, oxacillin and cefoxitin should be used as surrogate markers for \u03b2-lactam susceptibility, as appropriate for the\n                        <jats:italic toggle=\"yes\">Staphylococcus<\/jats:italic>\n                        species, to minimize the risk of reporting false susceptible results. The clarification of these criteria by the Clinical and Laboratory Standards Institute in VET01S will enhance diagnostic accuracy, aid effective antimicrobial stewardship, and improve clinical outcomes in veterinary medicine.\n                      <\/jats:p>\n                    <\/jats:sec>\n                  <\/jats:sec>","DOI":"10.1128\/jcm.00168-26","type":"journal-article","created":{"date-parts":[[2026,6,12]],"date-time":"2026-06-12T13:05:26Z","timestamp":1781269526000},"update-policy":"https:\/\/doi.org\/10.1128\/asmj-crossmark-policy-page","source":"Crossref","is-referenced-by-count":2,"title":["Evaluating veterinary\n                    <i>Staphylococcus<\/i>\n                    \u03b2-lactam breakpoint performance: a comparative analysis of individual agents versus oxacillin as a surrogate"],"prefix":"10.1128","volume":"64","author":[{"ORCID":"https:\/\/orcid.org\/0009-0003-8876-5445","authenticated-orcid":true,"given":"Sarah J.","family":"Gefroh","sequence":"first","affiliation":[{"id":[{"id":"https:\/\/ror.org\/05h1bnb22","id-type":"ROR","asserted-by":"publisher"}],"name":"Veterinary Diagnostic Laboratory, North Dakota State University","place":["Fargo, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0009-3521-095X","authenticated-orcid":true,"given":"Briena M.","family":"Meier","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/05h1bnb22","id-type":"ROR","asserted-by":"publisher"}],"name":"Veterinary Diagnostic Laboratory, North Dakota State University","place":["Fargo, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Robert R.","family":"Bowden","sequence":"additional","affiliation":[{"name":"Department of Pathology, Beth Israel Deaconess Medical Center","place":["Boston, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3553-9263","authenticated-orcid":true,"given":"Daniel R.","family":"Evans","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/04g43x563","id-type":"ROR","asserted-by":"publisher"}],"name":"Minnesota Department of Health","place":["St. Paul, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5121-950X","authenticated-orcid":true,"given":"Kelli J.","family":"Maddock","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/05h1bnb22","id-type":"ROR","asserted-by":"publisher"}],"name":"Veterinary Diagnostic Laboratory, North Dakota State University","place":["Fargo, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"235","reference":[{"key":"e_1_3_3_2_2","doi-asserted-by":"publisher","DOI":"10.1128\/CMR.00020-18"},{"key":"e_1_3_3_3_2","unstructured":"CLSI. 2025. CLSI supplement M100. In Performance standards for antimicrobial susceptibility testing 35th ed. Clinical and Laboratory Standards Institute."},{"key":"e_1_3_3_4_2","volume-title":"Clinical Microbiology Procedures Handbook","author":"Leber AL","year":"2023","unstructured":"Leber AL, Burnham CAD, eds. 2023. Chapter 7.1: Types of antimicrobial susceptibility tests. In Clinical Microbiology Procedures Handbook, 5th ed. ASM Press, Washington, DC.","edition":"5"},{"key":"e_1_3_3_5_2","doi-asserted-by":"publisher","DOI":"10.1093\/cid\/ciu043"},{"key":"e_1_3_3_6_2","unstructured":"European Committee on Antimicrobial Susceptibilit Testing (EUCAST). 2026. Breakpoint tables for interpretation of MICs and zone diameters version 16.0. Available from: https:\/\/www.eucast.org\/fileadmin\/eucast\/pdf\/breakpoints\/v_16.0_Breakpoint_Tables.pdf"},{"key":"e_1_3_3_7_2","volume-title":"VET01S: performance standards for antimicrobial disk and dilution susceptibility tests for bacteria isolated from animals","author":"CLSI","year":"2024","unstructured":"CLSI. 2024. VET01S: performance standards for antimicrobial disk and dilution susceptibility tests for bacteria isolated from animals. 7th ed. Clinical and Laboratory Standards Institute.","edition":"7"},{"key":"e_1_3_3_8_2","doi-asserted-by":"publisher","DOI":"10.1177\/104063870902100108"},{"key":"e_1_3_3_9_2","doi-asserted-by":"publisher","DOI":"10.1177\/104063870902100514"},{"key":"e_1_3_3_10_2","doi-asserted-by":"publisher","DOI":"10.1128\/JCM.02864-15"},{"key":"e_1_3_3_11_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.vetmic.2021.109006"},{"key":"e_1_3_3_12_2","unstructured":"Food and Drug Administration (FDA). 2025. Vet-LIRN. Laurel MD. 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