{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,31]],"date-time":"2026-10-31T17:57:54Z","timestamp":1793469474162,"version":"4.5.0"},"reference-count":42,"publisher":"Oxford University Press (OUP)","issue":"4","license":[{"start":{"date-parts":[[2023,7,22]],"date-time":"2023-07-22T00:00:00Z","timestamp":1689984000000},"content-version":"vor","delay-in-days":11,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100004440","name":"Wellcome Trust","doi-asserted-by":"publisher","award":["110085\/Z\/15\/Z"],"award-info":[{"award-number":["110085\/Z\/15\/Z"]}],"id":[{"id":"10.13039\/100004440","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2023,7,11]]},"abstract":"<jats:title>Abstract<\/jats:title>\n               <jats:sec>\n                  <jats:title>Objectives<\/jats:title>\n                  <jats:p>We investigated longitudinally Vietnamese small-scale chicken flocks in order to characterize changes in antimicrobial resistance gene (ARG) content over their life cycle, and the impact of antimicrobial use (AMU) on an intervention consisting of veterinary advice provision.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Methods<\/jats:title>\n                  <jats:p>AMU data and faecal samples were collected from 83 flocks (25 farms) at day-old, mid- and late-production (\u223c4\u2005month cycle). Using high-throughput real-time PCR, samples were investigated for 94 ARGs. ARG copies were related to 16S rRNA and ng of DNA (ngDNA). Impact of AMU and ARGs in day-olds was investigated by mixed-effects models.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Results<\/jats:title>\n                  <jats:p>Flocks received a mean (standard error, SE) animal daily dose (ADD) of 736.7 (83.0) and 52.1 (9.9)\u2005kg in early and late production, respectively. Overall, ARGs\/16S rRNA increased from day-old (mean 1.47; SE 0.10) to mid-production (1.61; SE 0.16), further decreasing in end-production (1.60; SE 0.1) (all P\u200a&amp;gt;\u200a0.05). In mid-production, ARGs\/16S rRNA increased for aminoglycosides, phenicols, sulphonamides and tetracyclines, decreasing for polymyxins \u03b2-lactams and genes that confer resistance to mutiple classes (multi-drug resistance) (MDR). At end-production, aminoglycoside resistance decreased and polymyxin and quinolone resistance increased (all P\u200a&amp;lt;\u200a0.05). Results in relation to ngDNA gave contradictory results. Neither AMU nor ARGs in day-olds had an impact on subsequent ARG abundance. The intervention resulted in 74.2% AMU reduction; its impact on ARGs depended on whether ARGs\/ngDNA (+14.8%) or ARGs\/16S rRNA metrics (\u221210.7%) (P\u200a&amp;gt;\u200a0.05) were computed.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Conclusions<\/jats:title>\n                  <jats:p>The flocks\u2019 environment (contaminated water, feed and residual contamination) is likely to play a more important role in transmission of ARGs to flocks than previously thought. Results highlight intriguing differences in the quantification of ARGs depending on the metric chosen.<\/jats:p>\n               <\/jats:sec>","DOI":"10.1093\/jacamr\/dlad090","type":"journal-article","created":{"date-parts":[[2023,7,22]],"date-time":"2023-07-22T16:33:10Z","timestamp":1690043590000},"source":"Crossref","is-referenced-by-count":3,"title":["Impact of antimicrobial use on abundance of antimicrobial resistance genes in chicken flocks in Vietnam"],"prefix":"10.1093","volume":"5","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6167-3976","authenticated-orcid":false,"given":"Nguyen Thi","family":"Nhung","sequence":"first","affiliation":[{"name":"Oxford University Clinical Research Unit , Ho Chi Minh City , Vietnam"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Avijit","family":"Dutta","sequence":"additional","affiliation":[{"name":"Cambridge Institute of Therapeutic Immunology & Infectious Disease, University of Cambridge , Cambridge , UK"},{"name":"Chattogram Veterinary and Animal Sciences University , Chattogram 4225 , Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ellen","family":"Higginson","sequence":"additional","affiliation":[{"name":"Cambridge Institute of Therapeutic Immunology & Infectious Disease, University of Cambridge , Cambridge , UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Leanne","family":"Kermack","sequence":"additional","affiliation":[{"name":"Cambridge Institute of Therapeutic Immunology & Infectious Disease, University of Cambridge , Cambridge , UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nguyen Thi Phuong","family":"Yen","sequence":"additional","affiliation":[{"name":"Oxford University Clinical Research Unit , Ho Chi Minh City , Vietnam"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Doan Hoang","family":"Phu","sequence":"additional","affiliation":[{"name":"Oxford University Clinical Research Unit , Ho Chi Minh City , Vietnam"},{"name":"Faculty of Animal Science and Veterinary Medicine, Nong Lam University , Ho Chi Minh City , Vietnam"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bach Tuan","family":"Kiet","sequence":"additional","affiliation":[{"name":"Sub-Department of Animal Health and Production , Dong Thap Province, Cao Lanh , Vietnam"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5187-6390","authenticated-orcid":false,"given":"Marc","family":"Choisy","sequence":"additional","affiliation":[{"name":"Oxford University Clinical Research Unit , Ho Chi Minh City , Vietnam"},{"name":"Centre for Tropical Medicine and Global Health, University of Oxford , Oxford , UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ronald B","family":"Geskus","sequence":"additional","affiliation":[{"name":"Oxford University Clinical Research Unit , Ho Chi Minh City , Vietnam"},{"name":"Centre for Tropical Medicine and Global Health, University of Oxford , Oxford , UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stephen","family":"Baker","sequence":"additional","affiliation":[{"name":"Cambridge Institute of Therapeutic Immunology & Infectious Disease, University of Cambridge , Cambridge , UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9161-8890","authenticated-orcid":false,"given":"Juan","family":"Carrique-Mas","sequence":"additional","affiliation":[{"name":"Oxford University Clinical Research Unit , Ho Chi Minh City , Vietnam"},{"name":"Centre for Tropical Medicine and Global Health, University of Oxford , Oxford , UK"},{"name":"Food and Agriculture Organization of the United Nations (FAO) , Hanoi , Vietnam"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[2023,7,22]]},"reference":[{"key":"2023072216330023400_dlad090-B1","doi-asserted-by":"crossref","first-page":"629","DOI":"10.1016\/S0140-6736(21)02724-0","article-title":"Global burden of bacterial antimicrobial resistance in 2019: a systematic analysis","volume":"399","author":"Antimicrobial Resistance Collaborators","year":"2022","journal-title":"Lancet"},{"key":"2023072216330023400_dlad090-B2","doi-asserted-by":"crossref","first-page":"eaaw1944","DOI":"10.1126\/science.aaw1944","article-title":"Global trends in antimicrobial resistance in animals in low- and middle-income countries","volume":"365","author":"van Boeckel","year":"2019","journal-title":"Science"},{"key":"2023072216330023400_dlad090-B3","doi-asserted-by":"crossref","first-page":"16","DOI":"10.1186\/s13756-019-0671-7","article-title":"An estimation of total antimicrobial usage in humans and animals in 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