{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,1]],"date-time":"2026-09-01T18:17:19Z","timestamp":1788286639698,"version":"build-2803163510"},"reference-count":50,"publisher":"Public Library of Science (PLoS)","issue":"9","license":[{"start":{"date-parts":[[2026,9,1]],"date-time":"2026-09-01T00:00:00Z","timestamp":1788220800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["www.plospathogens.org"],"crossmark-restriction":false},"short-container-title":["PLoS Pathog"],"abstract":"\n Background<\/jats:title>\n \n The rapid global spread of hypervirulence in Enterobacteriaceae, particularly in carbapenem-resistant\n Klebsiella pneumoniae<\/jats:italic>\n , poses a significant public health threat. However, the key genetic vehicles and mechanisms driving horizontal transfer of hypervirulence-associated genes (\n iucA<\/jats:italic>\n ,\n iroB<\/jats:italic>\n ,\n rmpA<\/jats:italic>\n ,\n rmpA2<\/jats:italic>\n , and\n peg-344<\/jats:italic>\n ) remain poorly defined, limiting effective surveillance.\n <\/jats:p>\n <\/jats:sec>\n \n Methods<\/jats:title>\n We performed a large-scale genomic survey of 2,869 virulence-associated plasmid sequences and 2,337 complete Enterobacteriaceae chromosomes. Using comparative genomics and evolutionary analyses, we systematically identified and characterized Hypervirulence-associated Pseudo-Compound Transposons (Hva-PCTs), defined as structured mobile elements in which hypervirulence-associated genes are flanked by insertion sequences.<\/jats:p>\n <\/jats:sec>\n \n Results<\/jats:title>\n \n Our results demonstrate that hypervirulence-associated genes are transmitted primarily as discrete IS-bounded units, which we term Hva-PCTs. We identified 29 distinct plasmid-borne Hva-PCTs (pHva-PCTs) and 30 chromosomal Hva-PCTs (cHva-PCTs). These modules show clear species-specific patterns:\n iucA\/iroB<\/jats:italic>\n -associated Hva-PCTs mainly originate in\n Escherichia coli<\/jats:italic>\n and spread through IncFIB-containing multi-replicon plasmids (commonly combined with IncFIC(FII) and\/or IncFII, while\n rmpA\/rmpA2\/peg-344<\/jats:italic>\n -containing modules originate in\n K. pneumoniae<\/jats:italic>\n and are disseminated via IncHI1B\/repB plasmids. Three Hva-PCTs were detected on both plasmids and chromosomes (xHva-PCTs). In one clinical\n K. pneumoniae<\/jats:italic>\n isolate (LS356), the identical composite module was present on both replicons. Simpler sub-modules, such as IS\n Kqu3-rmpA2-iucA_1<\/jats:italic>\n -IS\n 102<\/jats:italic>\n and IS\n 102-rmpA-peg-344-iroB_1<\/jats:italic>\n -IS\n 1A<\/jats:italic>\n , frequently co-occur on the same plasmid; when positioned in tandem, they reconstitute the full composite structure. This assembly pattern is further supported by a partial duplication event in plasmid pP901. CD-HIT clustering (80% nucleotide identity and 90% coverage) showed that 13 of 22 major clusters contained both plasmid and chromosomal copies, with intra-cluster identities >80% across multiple sequence types and host species.\n <\/jats:p>\n <\/jats:sec>\n \n Conclusion<\/jats:title>\n Hypervirulence-associated genes in Enterobacteriaceae are disseminated mainly as IS-flanked Hva-PCTs rather than solely through intact virulence plasmids. These modules exhibit strong but not absolute host specificity. The presence of identical Hva-PCTs on plasmids and chromosomes suggests inter-replicon mobility, while their stepwise assembly from simpler sub-modules highlights modular accretion as a key evolutionary process. Tracking Hva-PCTs as distinct mobile units may complement existing plasmid- and gene-centric surveillance approaches for hypervirulent and convergent strains. Experimental validation of their transposition activity and phenotypic effects is still required.<\/jats:p>\n <\/jats:sec>","DOI":"10.1371\/journal.ppat.1014513","type":"journal-article","created":{"date-parts":[[2026,9,1]],"date-time":"2026-09-01T17:50:52Z","timestamp":1788285052000},"page":"e1014513","update-policy":"https:\/\/doi.org\/10.1371\/journal.ppat.corrections_policy","source":"Crossref","is-referenced-by-count":0,"title":["Hypervirulence-associated pseudo-compound transposons as fundamental mobile units driving cross-species virulence dissemination in Enterobacteriaceae"],"prefix":"10.1371","volume":"22","author":[{"given":"Shuaihua","family":"Fan","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lijun","family":"Wang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chao","family":"Liu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Haoran","family":"Li","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Huaiqing","family":"Qi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pengcheng","family":"Du","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7374-2465","authenticated-orcid":true,"given":"Jun","family":"Guo","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2026,9,1]]},"reference":[{"issue":"10369","key":"ppat.1014513.ref001","doi-asserted-by":"crossref","first-page":"2221","DOI":"10.1016\/S0140-6736(22)02185-7","article-title":"Global 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of Hypervirulent Klebsiella pneumoniae from Classical K. pneumoniae","volume":"56","author":"TA Russo","year":"2018","journal-title":"J Clin Microbiol"},{"issue":"3","key":"ppat.1014513.ref005","doi-asserted-by":"crossref","DOI":"10.1128\/CMR.00001-19","article-title":"Hypervirulent Klebsiella pneumoniae","volume":"32","author":"TA Russo","year":"2019","journal-title":"Clin Microbiol Rev"},{"issue":"6","key":"ppat.1014513.ref006","doi-asserted-by":"crossref","first-page":"344","DOI":"10.1038\/s41579-019-0315-1","article-title":"Population genomics of Klebsiella pneumoniae","volume":"18","author":"KL Wyres","year":"2020","journal-title":"Nat Rev Microbiol"},{"issue":"1","key":"ppat.1014513.ref007","doi-asserted-by":"crossref","first-page":"77","DOI":"10.1186\/s13073-018-0587-5","article-title":"Tracking key virulence loci encoding aerobactin and salmochelin siderophore synthesis in Klebsiella pneumoniae","volume":"10","author":"MMC Lam","year":"2018","journal-title":"Genome 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