{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T04:42:10Z","timestamp":1788410530400,"version":"build-2803163510"},"reference-count":26,"publisher":"Oxford University Press (OUP)","issue":"4","license":[{"start":{"date-parts":[[2025,4,1]],"date-time":"2025-04-01T00:00:00Z","timestamp":1743465600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/pages\/standard-publication-reuse-rights"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2025,11,6]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Rapid administration of effective antimicrobial therapy is crucial for managing bloodstream infections (BSIs), especially those caused by pathogens with difficult-to-treat resistance (DTR; ie, resistance to all first-line antimicrobials). The purpose of this study is to describe the epidemiology and time course of microbiological testing in US laboratories for gram-negative BSIs (GN-BSIs).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>A retrospective observational cohort study of adults with GN-BSI between 1 January 2017 and 30 June 2023 was conducted using a large, geographically diverse, hospital-based administrative US database. Antimicrobial susceptibility testing (AST) reporting and time to results of traditional and next-generation antimicrobials (ceftazidime-avibactam, ceftolozane-tazobactam, cefiderocol, meropenem-vaborbactam, imipenem-relebactam) were evaluated according to the isolates\u2019 resistance phenotype.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>A total of 110 322 GN-BSI episodes were included, of which 0.6% exhibited a DTR phenotype. Among all episodes, the average time to results for AST was 73.5 \u00b1 26.7 hours from blood culture collection. The average time to AST results was longer for DTR (92.2 \u00b1 27.8 hours) and carbapenem not-susceptible phenotypes (90.1 \u00b1 28.0 hours) than for nonresistant phenotypes (72.9 \u00b1 26.7 hours). Overall, 2.5% of GN-BSI episodes had AST reported for at least 1 next-generation antimicrobial, increasing from 0.2% in 2017 to 7.7% in 2023. Among patients with isolates showing DTR phenotypes, 30.5% had AST reported for at least 1 next-generation antimicrobial.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Time to AST results for next-generation antimicrobials and antibiotic-resistant organisms is prolonged in US laboratories for blood cultures with gram-negative organisms. Testing frequency and timing of AST reporting for next-generation antimicrobials likely contribute to their clinical utilization.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1093\/cid\/ciaf165","type":"journal-article","created":{"date-parts":[[2025,4,1]],"date-time":"2025-04-01T04:48:46Z","timestamp":1743482926000},"page":"710-720","source":"Crossref","is-referenced-by-count":4,"title":["Microbiology Laboratory Testing Practices of Gram-Negative Bloodstream Infections With Difficult-to-Treat Resistant Phenotypes in US Hospitals"],"prefix":"10.1093","volume":"81","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8019-2270","authenticated-orcid":false,"given":"Shawn H","family":"MacVane","sequence":"first","affiliation":[{"name":"Global Medical Affairs, bioM\u00e9rieux , Hazelwood, Missouri 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