{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,9]],"date-time":"2026-09-09T06:07:36Z","timestamp":1788934056215,"version":"build-2803163510"},"reference-count":27,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,9,9]],"date-time":"2026-09-09T00:00:00Z","timestamp":1788912000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100015763","name":"Szegedi Tudom\u00e1nyegyetem","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100015763","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Microbiol."],"abstract":"\n Background<\/jats:title>\n \n In\n Bacteroides<\/jats:italic>\n strains, metronidazole resistance is encoded mainly by the so-called\n nim<\/jats:italic>\n genes, which are usually carried on plasmids; however, chromosomal presence is also known (e.g.,\n nimB<\/jats:italic>\n ). Usually, the\n nim<\/jats:italic>\n genes are activated by insertion sequence (IS) elements, conferring resistance. Molecular epidemiological observations predict that this configuration most likely arose before the formation of the best-known carrier mobile genetic elements.\n <\/jats:p>\n <\/jats:sec>\n \n Objective<\/jats:title>\n \n To determine the\n nimB<\/jats:italic>\n genetic element and study its evolution.\n <\/jats:p>\n <\/jats:sec>\n \n Methods<\/jats:title>\n \n To fulfill the goals, the whole-genome sequence of\n B. fragilis<\/jats:italic>\n BF8, inverse PCRs, and bioinformatic analyses were used.\n <\/jats:p>\n <\/jats:sec>\n \n Results<\/jats:title>\n \n A novel mobilizable transposon, MTn\n Bf8<\/jats:italic>\n , is described, with an integrated part, Tn\n NimB1<\/jats:italic>\n , that carries the chromosomal\n nimB<\/jats:italic>\n gene. Cassettes similar to Tn\n NimB1<\/jats:italic>\n were found in\n Bacteroides<\/jats:italic>\n -related species in fecal metagenomes, but these species did not harbor IS\n 1168<\/jats:italic>\n . In inverse PCR, the excised intermediates of MTn\n Bf8<\/jats:italic>\n and Tn\n NimB1<\/jats:italic>\n were detected, thereby confirming their mobility. In alignments of nucleotide and protein sequences, the existence of the Tn\n NimB<\/jats:italic>\n s and at least three groups of integrative elements of\n Bacteroides<\/jats:italic>\n could be confirmed, and a scheme for the emergence of different\n nimB-<\/jats:italic>\n carrying elements was drawn.\n <\/jats:p>\n <\/jats:sec>\n \n Conclusion<\/jats:title>\n \n The data presented here could explain the above-mentioned emergence of MTn\n Bf8<\/jats:italic>\n \/Tn\n NimB1<\/jats:italic>\n and the IS-\n nimB<\/jats:italic>\n configurations and their expected spread.\n <\/jats:p>\n <\/jats:sec>","DOI":"10.3389\/fmicb.2026.1923328","type":"journal-article","created":{"date-parts":[[2026,9,9]],"date-time":"2026-09-09T05:58:44Z","timestamp":1788933524000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Description and evolution of a nimB gene-coding, composite mobilizable transposon, MTnBf8, of Bacteroides fragilis"],"prefix":"10.3389","volume":"17","author":[{"given":"J\u00f3zsef","family":"S\u00f3ki","sequence":"first","affiliation":[{"name":"Institute of Medical Microbiology, Albert Szent-Gy\u00f6rgyi Medical School and Health Centre, University of Szeged","place":["Szeged, Hungary"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,9,9]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"29","DOI":"10.1016\/j.anaerobe.2018.10.005","article-title":"A sequence database analysis of 5-nitroimidazole reductase and related proteins to expand knowledge on enzymes responsible for metronidazole inactivation.","volume":"55","author":"Alauzet","year":"","journal-title":"Anaerobe"},{"key":"B2","doi-asserted-by":"publisher","first-page":"40","DOI":"10.1016\/j.anaerobe.2018.10.004","article-title":"Metronidazole resistance and nim genes in anaerobes: A review.","volume":"55","author":"Alauzet","year":"","journal-title":"Anaerobe"},{"key":"B3","doi-asserted-by":"publisher","first-page":"60","DOI":"10.1128\/AAC.01003-09","article-title":"Metronidazole resistance in Prevotella spp. and description of a new nim gene in Prevotella baroniae.","volume":"54","author":"Alauzet","year":"2010","journal-title":"Antimicrob. 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