{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T23:56:31Z","timestamp":1791849391638,"version":"4.3.4"},"reference-count":53,"publisher":"American Society for Microbiology","issue":"2","license":[{"start":{"date-parts":[[2026,2,3]],"date-time":"2026-02-03T00:00:00Z","timestamp":1770076800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,2,3]],"date-time":"2026-02-03T00:00:00Z","timestamp":1770076800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.asm.org\/non-commercial-tdm-license"}],"content-domain":{"domain":["journals.asm.org"],"crossmark-restriction":true},"short-container-title":["Microbiol Spectr"],"published-print":{"date-parts":[[2026,2,3]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:sec>\n                    <jats:title\/>\n                    <jats:p>\n                      Hypervirulent\n                      <jats:italic toggle=\"yes\">Klebsiella pneumoniae<\/jats:italic>\n                      species complex (hvKp) can cause invasive infections with spontaneous abscesses, also in previously healthy individuals. In contrast to Asia, hvKp is considered rare in Europe but has received more attention in the last few years, especially carbapenemase-producing strains. The aim of this prospective survey was to determine the occurrence and clinical, epidemiological, and genomic characteristics of\n                      <jats:italic toggle=\"yes\">K. pneumonia<\/jats:italic>\n                      e species complex (KpSC) infections leading to spontaneous abscesses in Dutch patients. All Dutch medical microbiology laboratories (\n                      <jats:italic toggle=\"yes\">n<\/jats:italic>\n                      = 51) were requested to submit KpSC isolates from 2022, that were suspected to be hypervirulent based on clinical criteria, with a spontaneous abscess as the most important criterium. Short-read sequencing (also combined with long-read sequencing for hybrid assemblies) was performed to analyze virulence factors and antimicrobial resistance genes and genetic relatedness by whole-genome multilocus sequence typing (wgMLST). In total, 33 KpSC isolates from 33 patients were submitted of whom 64% had a liver abscess and 64% had bacteremia. Among 31 patients with comorbidity information, 48% had no comorbidity. Isolates were susceptible to commonly used antibiotics. Six (18%) isolates did not have the salmochelin, yersiniabactin, aerobactin, colibactin,\n                      <jats:italic toggle=\"yes\">rmpADC,<\/jats:italic>\n                      or\n                      <jats:italic toggle=\"yes\">rmpA2<\/jats:italic>\n                      gene (clusters). Thirty-six percent of isolates had a maximum Kleborate virulence score. Thirty percent were ST23. WgMLST of the isolates showed low genetic relatedness compared to each other and to 720 international hypervirulent and\/or ST23 KpSC isolates from NCBI. In conclusion, this study suggests that hvKp strains do occur but are relatively uncommon in Dutch patients and differ from international strains. No carbapenemase-producers were found among study isolates. When existing microbiological\/molecular definitions would be used, several spontaneous abscesses could not be explained.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>IMPORTANCE<\/jats:title>\n                    <jats:p>\n                      Hypervirulent\n                      <jats:italic toggle=\"yes\">Klebsiella pneumoniae<\/jats:italic>\n                      species complex (hvKp) can lead to severe infections with abscesses in previously healthy individuals. HvKp is considered rare in Europe but has received more attention recently. A complicating factor is the absence of a clear microbiological\/molecular definition of hvKp. The aim of this survey was to determine occurrence and characteristics of\n                      <jats:italic toggle=\"yes\">K. pneumoniae<\/jats:italic>\n                      species complex (KpSC) infections leading to spontaneous abscesses, suggestive of hvKp, in Dutch patients. Dutch medical microbiology laboratories were requested to submit KpSC isolates cultured in 2022 from patients with spontaneous abscesses. This study suggests that hvKp is relatively uncommon in Dutch patients with only 33 collected isolates. The isolates were susceptible to commonly used antibiotics. Genetic characteristics were very diverse. We found low genetic relatedness compared to each other and to international hvKp isolates. When existing microbiological\/molecular definitions of hvKp would be used, several spontaneous abscesses from this study could not be explained.\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.1128\/spectrum.02259-25","type":"journal-article","created":{"date-parts":[[2026,1,12]],"date-time":"2026-01-12T14:01:15Z","timestamp":1768226475000},"update-policy":"https:\/\/doi.org\/10.1128\/asmj-crossmark-policy-page","source":"Crossref","is-referenced-by-count":2,"title":["Genomic epidemiology of putative hypervirulent\n                    <i>Klebsiella pneumoniae<\/i>\n                    species complex in Dutch patients, January\u2013December 2022"],"prefix":"10.1128","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9259-4920","authenticated-orcid":true,"given":"Karuna E. 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