{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,15]],"date-time":"2026-10-15T21:57:43Z","timestamp":1792101463383,"version":"4.4.0"},"reference-count":36,"publisher":"American Society for Microbiology","issue":"3","license":[{"start":{"date-parts":[[2025,3,5]],"date-time":"2025-03-05T00:00:00Z","timestamp":1741132800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2025,3,5]],"date-time":"2025-03-05T00:00:00Z","timestamp":1741132800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.asm.org\/non-commercial-tdm-license"}],"funder":[{"name":"HHS | National Institutes of Health","award":["R21AI173475"],"award-info":[{"award-number":["R21AI173475"]}]}],"content-domain":{"domain":["journals.asm.org"],"crossmark-restriction":true},"short-container-title":["Antimicrob Agents Chemother"],"published-print":{"date-parts":[[2025,3,5]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n          <jats:sec>\n            <jats:title\/>\n            <jats:p>\n              Ceftriaxone-resistant Enterobacterales remain a public health threat; contemporary data investigating their molecular epidemiology are limited. Five hundred consecutive ceftriaxone-resistant (MIC \u2265 4 \u00b5g\/mL) Enterobacterales bloodstream isolates were collected between 2018 and 2022 from three Maryland hospitals. Broth microdilution confirmed antibiotic susceptibilities. Whole-genome sequencing identified extended-spectrum \u03b2-lactamase (ESBL) and\n              <jats:italic>ampC<\/jats:italic>\n              genes both in bacterial chromosomes (c-\n              <jats:italic>ampC<\/jats:italic>\n              ) and on plasmids (p-\n              <jats:italic>ampC<\/jats:italic>\n              ). Mutations in promoter or attenuator regions of the\n              <jats:italic>Escherichia coli<\/jats:italic>\n              c-\n              <jats:italic>ampC<\/jats:italic>\n              gene (i.e.,\n              <jats:italic>bla<\/jats:italic>\n              <jats:sub>EC<\/jats:sub>\n              gene) with the potential to result in\n              <jats:italic>ampC<\/jats:italic>\n              derepression were investigated. The presence of ESBL or\n              <jats:italic>ampC<\/jats:italic>\n              genes was confirmed in 497 (99.4%) isolates. Two hundred seventy-nine (55.8%) isolates had both ESBL and\n              <jats:italic>ampC<\/jats:italic>\n              genes. ESBL families were identified among 398 (80%) patients:\n              <jats:italic>bla<\/jats:italic>\n              <jats:sub>CTX-M<\/jats:sub>\n              (\n              <jats:italic>n<\/jats:italic>\n              = 370),\n              <jats:italic>bla<\/jats:italic>\n              <jats:sub>SHV<\/jats:sub>\n              (\n              <jats:italic>n<\/jats:italic>\n              = 17),\n              <jats:italic>bla<\/jats:italic>\n              <jats:sub>OXY<\/jats:sub>\n              (\n              <jats:italic>n<\/jats:italic>\n              = 14), and\n              <jats:italic>bla<\/jats:italic>\n              <jats:sub>VEB<\/jats:sub>\n              (\n              <jats:italic>n<\/jats:italic>\n              = 5). Ceftriaxone-resistant Enterobacterales species carrying ESBL genes included the following:\n              <jats:italic>E. coli<\/jats:italic>\n              (67%),\n              <jats:italic>Klebsiella pneumoniae<\/jats:italic>\n              (24%),\n              <jats:italic>Klebsiella oxytoca<\/jats:italic>\n              (4%),\n              <jats:italic>Proteus mirabilis<\/jats:italic>\n              (2%),\n              <jats:italic>Enterobacter cloacae<\/jats:italic>\n              complex (2%),\n              <jats:italic>Klebsiella aerogenes<\/jats:italic>\n              (1%),\n              <jats:italic>Providencia stuartii<\/jats:italic>\n              (&lt;1%), and\n              <jats:italic>Serratia marcescens<\/jats:italic>\n              (&lt;1%). c-\n              <jats:italic>ampC<\/jats:italic>\n              genes were identified in 374 (75%) of the 500 isolates. Only 7% of\n              <jats:italic>E. coli<\/jats:italic>\n              isolates with mutations in the promoter or attenuator region of the c-\n              <jats:italic>ampC<\/jats:italic>\n              gene exhibited resistance to cefoxitin, a proxy for increased AmpC production. Two p-\n              <jats:italic>ampC<\/jats:italic>\n              genes were confirmed in 25 (5%) of the 500 isolates:\n              <jats:italic>bla<\/jats:italic>\n              <jats:sub>CMY-59<\/jats:sub>\n              (72%) and\n              <jats:italic>bla<\/jats:italic>\n              <jats:sub>DHA-1<\/jats:sub>\n              (28%; confined to\n              <jats:italic>E. coli<\/jats:italic>\n              [92%] and\n              <jats:italic>K. pneumoniae<\/jats:italic>\n              [8%]). Until comprehensive \u03b2-lactamase molecular testing is available, the species-specific prevalence of ESBL and\n              <jats:italic>ampC<\/jats:italic>\n              genes in ceftriaxone-resistant Enterobacterales should be considered to promote effective albeit judicious antibiotic prescribing. Mutations in promoter or attenuator regions of the\n              <jats:italic>E. coli<\/jats:italic>\n              c-\n              <jats:italic>ampC<\/jats:italic>\n              gene do not appear to contribute significantly to increased AmpC production in this species.\n            <\/jats:p>\n          <\/jats:sec>","DOI":"10.1128\/aac.01258-24","type":"journal-article","created":{"date-parts":[[2025,1,27]],"date-time":"2025-01-27T14:00:36Z","timestamp":1737986436000},"update-policy":"https:\/\/doi.org\/10.1128\/asmj-crossmark-policy-page","source":"Crossref","is-referenced-by-count":12,"title":["Molecular epidemiology of \u03b2-lactamases in ceftriaxone-resistant Enterobacterales bloodstream infections in the mid-Atlantic United States"],"prefix":"10.1128","volume":"69","author":[{"given":"Dariusz A.","family":"Hareza","sequence":"first","affiliation":[{"name":"Department of Medicine, Johns Hopkins University School of Medicine","place":["Baltimore, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yehudit","family":"Bergman","sequence":"additional","affiliation":[{"name":"Department of Pathology, Johns Hopkins University School of Medicine","place":["Baltimore, USA"]},{"name":"Department of Pediatrics, Johns Hopkins University School of Medicine","place":["Baltimore, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Emily","family":"Jacobs","sequence":"additional","affiliation":[{"name":"Department of Pathology, Johns Hopkins University School of Medicine","place":["Baltimore, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jennifer","family":"Lu","sequence":"additional","affiliation":[{"name":"Department of Pathology, Johns Hopkins University School of Medicine","place":["Baltimore, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nancy D.","family":"Hanson","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Immunology, Creighton School of Medicine","place":["Omaha, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rick","family":"Conzemius","sequence":"additional","affiliation":[{"name":"Ares Genetics","place":["Vienna, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sara E.","family":"Cosgrove","sequence":"additional","affiliation":[{"name":"Department of Medicine, Johns Hopkins University School of Medicine","place":["Baltimore, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anthony D.","family":"Harris","sequence":"additional","affiliation":[{"name":"Department of Epidemiology and Public Health, University of Maryland School of Medicine","place":["Baltimore, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6134-151X","authenticated-orcid":true,"given":"Patricia J.","family":"Simner","sequence":"additional","affiliation":[{"name":"Department of Medicine, Johns Hopkins University School of Medicine","place":["Baltimore, USA"]},{"name":"Department of Pathology, Johns Hopkins University School of Medicine","place":["Baltimore, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4143-6324","authenticated-orcid":true,"given":"Pranita D.","family":"Tamma","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, Johns Hopkins University School of Medicine","place":["Baltimore, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"235","reference":[{"key":"e_1_3_3_2_2","doi-asserted-by":"publisher","DOI":"10.1056\/NEJMoa1914433"},{"key":"e_1_3_3_3_2","doi-asserted-by":"publisher","DOI":"10.1093\/cid\/ciae403"},{"key":"e_1_3_3_4_2","doi-asserted-by":"publisher","DOI":"10.1128\/JCM.00127-21"},{"key":"e_1_3_3_5_2","doi-asserted-by":"publisher","DOI":"10.1093\/ofid\/ofad038"},{"key":"e_1_3_3_6_2","doi-asserted-by":"publisher","DOI":"10.1128\/JCM.01679-15"},{"key":"e_1_3_3_7_2","doi-asserted-by":"publisher","DOI":"10.1128\/JCM.00581-15"},{"key":"e_1_3_3_8_2","volume-title":"M100: performance standards for antimicrobial susceptibility testing","author":"Clinical and Laboratory Standards Institute","year":"2024","unstructured":"Clinical and Laboratory Standards Institute. 2024 M100: performance standards for antimicrobial susceptibility testing. 34th ed. 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