{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,6]],"date-time":"2026-05-06T15:14:21Z","timestamp":1778080461447,"version":"3.51.4"},"reference-count":29,"publisher":"Oxford University Press (OUP)","issue":"5","license":[{"start":{"date-parts":[[2026,4,29]],"date-time":"2026-04-29T00:00:00Z","timestamp":1777420800000},"content-version":"vor","delay-in-days":1,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,4,28]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>The impact of a shift in the epidemiology of ceftriaxone resistance among Escherichia coli and Klebsiella pneumoniae recovered from blood cultures was evaluated. 163 patients were included for analysis, 139 (85.3%) with blaCTX-M detected and 24 (14.7%) without blaCTX-M detected by molecular testing. All but 1 case in the no-CTX-M cohort occurred in 2024. Patients in the blaCTX-M detected cohort were started on optimal antimicrobial treatment significantly earlier than patients in the no blaCTX-M detected group (18.6 vs 59.2\u2005hours, P &amp;lt; .001). Between 2022 and 2024, the rate of CTX-M negative ceftriaxone-resistant E. coli (n = 14) and K. pneumoniae (n = 10) increased from 3.2% to 5.6% to 20.3%, while at the same time the rate of ceftriaxone susceptibility decreased for both species. Whole genome sequencing identified AmpC genes (blaCMY-2, blaDHA-1, and blaFOX-5), TEM extended-spectrum beta-lactamases (ESBL) variants (blaTEM-190) and SHV ESBL variants (blaSHV-12 and blaSHV-7) as the likely cause of ceftriaxone resistance in these isolates. Despite this change, the negative predictive value for the test was 94% in 2024. Our data suggest continued reliance on molecular testing for de-escalation is appropriate for most patients, although rapid follow-up of final susceptibility results is warranted. In addition, institutions should be aware that epidemiology changes may occur and routinely monitor the incidence of ceftriaxone resistant but blaCTX-M-negative isolates.<\/jats:p>","DOI":"10.1093\/ofid\/ofag225","type":"journal-article","created":{"date-parts":[[2026,4,22]],"date-time":"2026-04-22T11:47:01Z","timestamp":1776858421000},"source":"Crossref","is-referenced-by-count":0,"title":["Impact of a Rapid Change in Beta-lactam Resistance Epidemiology on the Management of Patients With Bloodstream Infections"],"prefix":"10.1093","volume":"13","author":[{"given":"Laura","family":"Bobbitt","sequence":"first","affiliation":[{"name":"Department of Pharmaceutical Services, Vanderbilt University Medical Center , Nashville, Tennessee ,","place":["USA"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9682-3911","authenticated-orcid":false,"given":"Lili","family":"Tao","sequence":"additional","affiliation":[{"name":"Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center , Nashville, Tennessee ,","place":["USA"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Benjamin","family":"Ereshefsky","sequence":"additional","affiliation":[{"name":"Department of Pharmaceutical Services, Vanderbilt University Medical Center , Nashville, Tennessee ,","place":["USA"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Austin","family":"Ing","sequence":"additional","affiliation":[{"name":"Department of Pharmaceutical Services, Vanderbilt University Medical Center , Nashville, Tennessee ,","place":["USA"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6568-156X","authenticated-orcid":false,"given":"Romney","family":"Humphries","sequence":"additional","affiliation":[{"name":"Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center , Nashville, Tennessee 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