{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,28]],"date-time":"2026-04-28T09:07:07Z","timestamp":1777367227287,"version":"3.51.4"},"reference-count":35,"publisher":"PeerJ","license":[{"start":{"date-parts":[[2026,4,28]],"date-time":"2026-04-28T00:00:00Z","timestamp":1777334400000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Key Research and Development Program of China","award":["2022YFE0199800"],"award-info":[{"award-number":["2022YFE0199800"]}]},{"name":"Qingdao Science and Technology Wellness Promotion Demonstration Program","award":["24-1-8-smjk-13-nsh"],"award-info":[{"award-number":["24-1-8-smjk-13-nsh"]}]},{"name":"SKLMT Frontiers and Challenges Project","award":["SKLMTFCP-2023-01]"],"award-info":[{"award-number":["SKLMTFCP-2023-01]"]}]},{"DOI":"10.13039\/501100014761","name":"Qingdao Natural Science Foundation","doi-asserted-by":"crossref","award":["24-4-4-zrjj-40-jch"],"award-info":[{"award-number":["24-4-4-zrjj-40-jch"]}],"id":[{"id":"10.13039\/501100014761","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"abstract":"<jats:sec>\n                    <jats:title>Objective<\/jats:title>\n                    <jats:p>\n                      <jats:italic>Acinetobacter baumannii<\/jats:italic>\n                      , a prevalent multidrug resistant (MDR) pathogen, poses a significant threat to critically ill patients. This work aims to analyze the genomes of eight clinical carbapenem-resistant\n                      <jats:italic>A. baumannii<\/jats:italic>\n                      (CRAB) strains, and to study the mechanisms and genomic context of antimicrobial resistance for this critical pathogen.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>\n                      Nanopore whole-genomic sequencing was performed and compared with carbapenem-susceptible\n                      <jats:italic>A. baumannii<\/jats:italic>\n                      strain to identify genomic context patterns of antibiotic resistance.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      Although some of these strains contain transferable plasmids, 121 of 122 antibiotic resistance genes (ARGs) identified are located on their chromosomes. Moreover, chromosomal ARGs clustered within recombinase-rich regions forming clear modules that are different from known resistance genomic islands. These modules are tandemly linked forming different combinations, and integrated at specific hot-spots\n                      <jats:italic>via<\/jats:italic>\n                      diverse mechanisms (direct repeats, fragment replacement, inverted repeats), suggesting that modular chromosomal plasticity leads to multidrug resistance in\n                      <jats:italic>A. baumannii<\/jats:italic>\n                      . Plasmid presence of these modules in other bacterial strains suggests they could have originated from plasmids.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>We find that modular chromosomal plasticity is the primary driver of carbapenem-resistance in our collection of CRAB isolates, which is a unique evolutionary strategy different from other ESKAPE pathogens. This study provides critical insights into CRAB genomic adaptability, and informs future strategies to combat their spread.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.7717\/peerj.21106","type":"journal-article","created":{"date-parts":[[2026,4,28]],"date-time":"2026-04-28T08:11:39Z","timestamp":1777363899000},"page":"e21106","source":"Crossref","is-referenced-by-count":0,"title":["The modular chromosomal genomic plasticity mediating high level antibiotic resistance in eight clinical carbapenem-resistant\n                    <i>Acinetobacter baumannii<\/i>\n                    strains"],"prefix":"10.7717","volume":"14","author":[{"given":"Shuai","family":"Wang","sequence":"first","affiliation":[{"name":"State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xinrou","family":"Zheng","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Microbial Technology, Shandong 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