{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,4]],"date-time":"2026-08-04T13:47:13Z","timestamp":1785851233963,"version":"3.56.0"},"reference-count":24,"publisher":"American Society for Microbiology","issue":"8","license":[{"start":{"date-parts":[[2026,8,5]],"date-time":"2026-08-05T00:00:00Z","timestamp":1785888000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,8,5]],"date-time":"2026-08-05T00:00:00Z","timestamp":1785888000000},"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":["K23AI114994"],"award-info":[{"award-number":["K23AI114994"]}],"id":[{"id":"10.13039\/100000060","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["journals.asm.org"],"crossmark-restriction":true},"short-container-title":["Antimicrob Agents Chemother"],"published-print":{"date-parts":[[2026,8,5]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:sec>\n                    <jats:title\/>\n                    <jats:p>\n                      Neutropenic patients colonized with extended-spectrum \u03b2-lactamase-producing Enterobacterales (ESBL-E) frequently develop ESBL-E bacteremia while receiving fluoroquinolone prophylaxis. However, the impact of colonization with ESBL-E and AmpC \u03b2-lactamase-producing Enterobacterales (AmpC-E) in neutropenic patients who do not receive fluoroquinolone prophylaxis is unclear. To investigate this, we conducted a prospective study of patients with acute leukemia or myelodysplastic syndrome (MDS) receiving induction chemotherapy without antibacterial prophylaxis between November 2015 and January 2020. Stool or perianal swab specimens were collected from study participants within 5 days of initiating chemotherapy and underwent culture for ESBL-E and AmpC-E. Isolated organisms were identified and subjected to antimicrobial susceptibility testing and whole-genome sequencing. Bacteremia risk during neutropenia was compared between ESBL-E-colonized, AmpC-E-colonized, and non-colonized patients. We enrolled 159 patients, of whom 15 (9%) were colonized with ESBL-E and 17 (11%) with AmpC-E. Fourteen (93%) of 15 colonizing ESBL-E isolates were cefepime resistant, compared to 2 (12%) of 17 AmpC-E isolates. Three (20%) of 15 ESBL-E-colonized patients developed ESBL-E bacteremia (colonizing and bloodstream isolates were genetically identical for each patient), compared to 1 (1%) of 144 patients without ESBL-E colonization (\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      = 0.001). ESBL-E-colonized patients were also more likely to develop bacteremia due to ceftriaxone-susceptible Enterobacterales than non-colonized patients. AmpC-E-colonized patients did not have an increased risk of gram-negative bacteremia. In patients with acute leukemia or MDS who receive induction chemotherapy without fluoroquinolone prophylaxis, ESBL-E colonization is associated with increased risk of gram-negative bacteremia due to ESBL-E and ceftriaxone-susceptible organisms. Screening for ESBL-E colonization in this population could optimize empirical antibacterial therapy.\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.1128\/aac.01738-25","type":"journal-article","created":{"date-parts":[[2026,6,26]],"date-time":"2026-06-26T13:55:46Z","timestamp":1782482146000},"update-policy":"https:\/\/doi.org\/10.1128\/asmj-crossmark-policy-page","source":"Crossref","is-referenced-by-count":0,"title":["Colonization with extended-spectrum and AmpC \u03b2-lactamase-producing Enterobacterales and bacteremia risk in patients with acute leukemia who receive induction chemotherapy without fluoroquinolone prophylaxis"],"prefix":"10.1128","volume":"70","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4507-8744","authenticated-orcid":false,"given":"Kate","family":"Stoeckle","sequence":"first","affiliation":[{"name":"Department of Medicine, Division of Infectious Diseases, Weill Cornell Medicine","place":["New York, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ivo","family":"Sah Bandar","sequence":"additional","affiliation":[{"name":"Department of Pathology and Laboratory Medicine, Weill Cornell Medicine","place":["New York, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5845-2235","authenticated-orcid":true,"given":"Liang","family":"Chen","sequence":"additional","affiliation":[{"name":"School of Pharmacy and Pharmaceutical Sciences, University at Buffalo","place":["Buffalo, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Claire","family":"Douglass","sequence":"additional","affiliation":[{"name":"NewYork-Presbyterian\/Weill Cornell Medical Center","place":["New York, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Emily","family":"Davidson","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/04rq5mt64","id-type":"ROR","asserted-by":"publisher"}],"name":"Department of Medicine, Division of Internal Medicine, University of Maryland","place":["Baltimore, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Michael","family":"Hovan","sequence":"additional","affiliation":[{"name":"NewYork-Presbyterian\/Weill Cornell Medical Center","place":["New York, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sierra","family":"Derti","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/0101kry21","id-type":"ROR","asserted-by":"publisher"}],"name":"Department of Medicine, Division of Internal Medicine, Allegheny Health Network","place":["Pittsburgh, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marisa","family":"La Spina","sequence":"additional","affiliation":[{"name":"NewYork-Presbyterian\/Weill Cornell Medical Center","place":["New York, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gail J.","family":"Roboz","sequence":"additional","affiliation":[{"name":"Department of Medicine, Division of Hematology and Medical Oncology, Weill Cornell Medicine","place":["New York, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Justin","family":"Kaner","sequence":"additional","affiliation":[{"name":"Department of Medicine, Division of Hematology and Medical Oncology, Weill Cornell Medicine","place":["New York, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"David","family":"Helfgott","sequence":"additional","affiliation":[{"name":"Department of Medicine, Division of Infectious Diseases, Weill Cornell Medicine","place":["New York, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0243-131X","authenticated-orcid":true,"given":"Barry N.","family":"Kreiswirth","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/04p5zd128","id-type":"ROR","asserted-by":"publisher"}],"name":"Center for Discovery and Innovation, Hackensack Meridian Health","place":["Nutley, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lars F.","family":"Westblade","sequence":"additional","affiliation":[{"name":"Department of Medicine, Division of Infectious Diseases, Weill Cornell Medicine","place":["New York, USA"]},{"name":"Department of Pathology and Laboratory Medicine, Weill Cornell Medicine","place":["New York, USA"]},{"name":"Department of Pediatrics, Division of Infectious Diseases, Weill Cornell Medicine","place":["New York, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4711-5334","authenticated-orcid":true,"given":"Michael J.","family":"Satlin","sequence":"additional","affiliation":[{"name":"Department of Medicine, Division of Infectious Diseases, Weill Cornell Medicine","place":["New York, USA"]},{"name":"Department of Pathology and Laboratory Medicine, Weill Cornell Medicine","place":["New York, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"235","reference":[{"key":"e_1_3_2_2_2","doi-asserted-by":"publisher","DOI":"10.1093\/cid\/ciq147"},{"key":"e_1_3_2_3_2","doi-asserted-by":"publisher","DOI":"10.1200\/JCO.18.00374"},{"key":"e_1_3_2_4_2","doi-asserted-by":"publisher","DOI":"10.1016\/0014-2964(73)90110-2"},{"key":"e_1_3_2_5_2","doi-asserted-by":"publisher","DOI":"10.3324\/haematol.2013.091025"},{"key":"e_1_3_2_6_2","doi-asserted-by":"publisher","DOI":"10.1093\/ofid\/ofac240"},{"key":"e_1_3_2_7_2","doi-asserted-by":"publisher","DOI":"10.1093\/ofid\/ofac005"},{"key":"e_1_3_2_8_2","doi-asserted-by":"publisher","DOI":"10.1093\/ofid\/ofw132"},{"key":"e_1_3_2_9_2","doi-asserted-by":"publisher","DOI":"10.1001\/jama.2018.12163"},{"key":"e_1_3_2_10_2","doi-asserted-by":"publisher","DOI":"10.1093\/cid\/ciae403"},{"key":"e_1_3_2_11_2","doi-asserted-by":"publisher","DOI":"10.1007\/s00277-011-1247-7"},{"key":"e_1_3_2_12_2","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0035780"},{"key":"e_1_3_2_13_2","doi-asserted-by":"publisher","DOI":"10.1007\/s00277-020-04144-w"},{"key":"e_1_3_2_14_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.jinf.2016.07.002"},{"key":"e_1_3_2_15_2","doi-asserted-by":"publisher","DOI":"10.1093\/cid\/ciy363"},{"key":"e_1_3_2_16_2","series-title":"CLSI 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Performance standards for antimicrobial susceptibility testing. 35th ed. CLSI Supplement M100. 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