{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,27]],"date-time":"2026-06-27T08:35:08Z","timestamp":1782549308772,"version":"3.54.5"},"reference-count":33,"publisher":"Oxford University Press (OUP)","issue":"5","license":[{"start":{"date-parts":[[2021,1,25]],"date-time":"2021-01-25T00:00:00Z","timestamp":1611532800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/journals\/pages\/open_access\/funder_policies\/chorus\/standard_publication_model"}],"funder":[{"DOI":"10.13039\/100000071","name":"National Institute of Child Health and Human Development","doi-asserted-by":"publisher","award":["HHSN275201000003I"],"award-info":[{"award-number":["HHSN275201000003I"]}],"id":[{"id":"10.13039\/100000071","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2021,5,28]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>Background<\/jats:title><jats:p>Premature, very low birth weight (VLBW) neonates are at risk for early-onset sepsis and receive ampicillin and gentamicin post-birth. Antimicrobial stewardship supports short-course antibiotics, but how long antibiotic concentrations remain therapeutic post-last dose is unknown.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>Using Monte Carlo simulations (NONMEM 7.3), we analyzed antibiotic exposures in a retrospective cohort of 34 689 neonates (&amp;lt;1500 g, 22-27 weeks of gestation). Therapeutic exposure for ampicillin and gentamicin was evaluated relative to the minimum inhibitory concentration (MIC) for common pathogens (MIC 0.25-8 mcg\/mL for group B streptococcus [GBS] and Escherichia coli). Post-discontinuation antibiotic exposure (PDAE) was defined as the time from the last dose to time when concentration decreased below MIC.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>Neonates had a median (range) gestational age of 26 (22-27) weeks and BW, 790 g (400-1497) . All ampicillin dosing regimens (50-100 mg\/kg every 8-12 hours for 2-6 doses) achieved therapeutic exposures &amp;gt; MIC range. After the last dose, the PDAE mean (95% confidence interval [CI]) ranged from 34 to 50 hours (17\u201379) for E. coli (MIC 8) and 82 to 104 hours (95% CI: 39-122) for GBS (MIC 0.25); longer PDAE occurred with higher dose, shorter interval, and longer course. Short-course ampicillin (2 doses, 50 mg\/kg every 12 hours) provided PDAE 34 hours for E. coli and 82 hours for GBS. Single-dose 5 mg\/kg gentamicin provided PDAE &amp;gt; MIC 2 for 26 hours.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>In VLBW neonates, ampicillin exposure remains therapeutic long after the last dose. Short-course ampicillin provided therapeutic exposures throughout the typical blood culture incubation period.<\/jats:p><\/jats:sec>","DOI":"10.1093\/jpids\/piaa172","type":"journal-article","created":{"date-parts":[[2020,12,28]],"date-time":"2020-12-28T20:12:46Z","timestamp":1609186366000},"page":"615-621","source":"Crossref","is-referenced-by-count":12,"title":["Prolonged Post-Discontinuation Antibiotic Exposure in Very Low Birth Weight Neonates at Risk for Early-Onset Sepsis"],"prefix":"10.1093","volume":"10","author":[{"given":"Jennifer","family":"Le","sequence":"first","affiliation":[{"name":"Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California\u2013San Diego, La Jolla, California, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rachel G","family":"Greenberg","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA"},{"name":"Duke Clinical Research 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