{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,25]],"date-time":"2026-06-25T17:51:12Z","timestamp":1782409872467,"version":"3.54.5"},"reference-count":24,"publisher":"Public Library of Science (PLoS)","issue":"6","license":[{"start":{"date-parts":[[2026,6,25]],"date-time":"2026-06-25T00:00:00Z","timestamp":1782345600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["81401696"],"award-info":[{"award-number":["81401696"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Shandong Provincial Natural Science Foundation General Project","award":["ZR2025MS1331"],"award-info":[{"award-number":["ZR2025MS1331"]}]},{"name":"Shandong Provincial Natural Science Foundations of China","award":["ZR2016HL44"],"award-info":[{"award-number":["ZR2016HL44"]}]},{"name":"Shandong Provincial Natural Science Foundations of China","award":["ZR2021MH214"],"award-info":[{"award-number":["ZR2021MH214"]}]}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS One"],"abstract":"<jats:sec id=\"sec001\">\n                    <jats:title>Objectives<\/jats:title>\n                    <jats:p>\n                      Although K64-type carbapenem-resistant hypervirulent\n                      <jats:italic>Klebsiella pneumoniae<\/jats:italic>\n                      (CR-hvKp) has been reported, its molecular characteristics remain unclear. This study aimed to characterize the phenotypic and molecular features of K64 putative hypervirulent CR-\n                      <jats:italic>K. pneumoniae<\/jats:italic>\n                      (phvKp)..\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"sec002\">\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>\n                      Two K64 putative hypervirulent CR-\n                      <jats:italic>K. pneumoniae<\/jats:italic>\n                      isolates were recovered from a patient in the emergency intensive care unit of a Chinese teaching hospital. Antimicrobial susceptibility testing was performed using broth microdilution method. Multilocus sequence typing (MLST) was used for molecular typing. Virulence was assessed using a mouse infection model, and whole-genome sequencing was performed to analyze resistance and virulence genes.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"sec003\">\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Both isolates were resistant to aztreonam, cephalosporins, carbapenems, quinolones, and aminoglycosides, but susceptible to trimethoprim\/sulfamethoxazole, colistin, tigecycline, and ceftazidime\/avibactam. MLST identified both isolates as ST11. The mouse infection model showed elevated virulence of two clinical isolates, which was significantly higher than that of the classical non-hypervirulent reference strain ATCC 13883. Genomic analysis identified 133 virulence- and pathogen-associated genes, including those involved in fimbriae synthesis, iron acquisition, and enterobactin production. Both isolates harbored the rmpA gene, but string tests were negative. Sequence alignment revealed &gt;80% similarity among 13 rmpA-harboring IncHI1B plasmids.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"sec004\">\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>\n                      K64 ST11-type phvKp has emerged in China, exhibiting multidrug resistance and putative hypervirulence characteristics. The increase in virulence of\n                      <jats:italic>K.pneumoniae<\/jats:italic>\n                      involves multiple factors, and these factors act independently or the synergistic effect leads to elevated virulence potential.\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.1371\/journal.pone.0351561","type":"journal-article","created":{"date-parts":[[2026,6,25]],"date-time":"2026-06-25T17:43:07Z","timestamp":1782409387000},"page":"e0351561","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":0,"title":["Phenotypic and molecular characterization of K64 putative hypervirulent carbapenem-resistant Klebsiella 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