{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,1]],"date-time":"2026-09-01T01:16:39Z","timestamp":1788225399677,"version":"build-2803163510"},"reference-count":42,"publisher":"American Society for Microbiology","issue":"7","license":[{"start":{"date-parts":[[2026,7,7]],"date-time":"2026-07-07T00:00:00Z","timestamp":1783382400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,7,7]],"date-time":"2026-07-07T00:00:00Z","timestamp":1783382400000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.asm.org\/non-commercial-tdm-license"}],"funder":[{"DOI":"10.13039\/501100019542","name":"Basic Research Project of Wenzhou City","doi-asserted-by":"publisher","award":["Y2020114"],"award-info":[{"award-number":["Y2020114"]}],"id":[{"id":"10.13039\/501100019542","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["journals.asm.org"],"crossmark-restriction":true},"short-container-title":["Microbiol Spectr"],"published-print":{"date-parts":[[2026,7,7]]},"abstract":"ABSTRACT<\/jats:title>\n \n \n \n This study investigated the virulence factors and two-component systems (TCS) expression in carbapenem-resistant\n Klebsiella pneumoniae<\/jats:italic>\n (CRKP) and carbapenem-susceptible\n Klebsiella pneumoniae<\/jats:italic>\n (CSKP). A total of 150 CRKP and 87 CSKP clinical isolates were collected from a tertiary hospital. Virulence genes, capsular serotypes, and hypermucoviscosity phenotype were detected. Serum resistance was assessed using serum killing assays, and virulence was preliminarily evaluated using the\n Galleria mellonella<\/jats:italic>\n larvae lethality assays as a supplement. TCS gene expression (\n phoQ<\/jats:italic>\n ,\n rstA<\/jats:italic>\n ,\n rcsB<\/jats:italic>\n , and\n ompR<\/jats:italic>\n ) was analyzed by qRT-PCR. The prevalence of hypervirulent\n K. pneumoniae<\/jats:italic>\n (hvKP, defined by the key virulence gene cluster\n rmpA\/rmpA2 + iucA + iroB + peg-344<\/jats:italic>\n ) was significantly lower in CRKP (carbapenem-resistant and hvKP [CR-hvKP], 5.3%) than in CSKP (CS-hvKP, 24.1%;\n P<\/jats:italic>\n < 0.05). CRKP exhibited lower carriage rates of\n rmpA<\/jats:italic>\n ,\n iroB<\/jats:italic>\n ,\n peg-344<\/jats:italic>\n ,\n aerobactin<\/jats:italic>\n ,\n alls<\/jats:italic>\n , and\n kfu<\/jats:italic>\n , but higher rates of\n rmpA2<\/jats:italic>\n and\n ybtS<\/jats:italic>\n compared to CSKP. CRKP was more likely to carry incomplete combinations of the key virulence genes than CSKP, with\n rmpA\/rmpA2 + iucA<\/jats:italic>\n being the most common. In CSKP, significant positive correlations were observed among virulence genes, but not in CRKP. In\n Galleria mellonella<\/jats:italic>\n assays, hvKP and CR-hvKP showed significantly lower survival rates than classical\n K. pneumoniae<\/jats:italic>\n and non-CR-hvKP (\n P<\/jats:italic>\n < 0.05). TCS genes (\n phoQ<\/jats:italic>\n ,\n rstA<\/jats:italic>\n , and\n ompR<\/jats:italic>\n ) were significantly upregulated in hvKP and CR-hvKP (\n P<\/jats:italic>\n < 0.05). CRKP exhibited reduced virulence gene carriage compared to CSKP, likely due to the loss of virulence genes during plasmid transmission. However, the high prevalence of the key virulence genes in CRKP underscores the potential for CR-hvKP dissemination, necessitating continued surveillance to prevent its spread. The upregulation of\n phoQ<\/jats:italic>\n ,\n rstA<\/jats:italic>\n , and\n ompR<\/jats:italic>\n in hvKP is associated with the hypervirulent phenotype, providing correlative clinical evidence that links the expression of these functionally established TCS to hypervirulence in clinical isolates.\n <\/jats:p>\n \n IMPORTANCE<\/jats:title>\n \n Carbapenem-resistant and hypervirulent\n Klebsiella pneumoniae<\/jats:italic>\n (CR-hvKP) presents a serious clinical threat by combining antibiotic resistance and hypervirulence. This study reveals critical differences in the virulence gene and phenotype between carbapenem-resistant\n K. pneumoniae<\/jats:italic>\n (CRKP) and carbapenem-susceptible\n K. pneumoniae<\/jats:italic>\n (CSKP). CRKP has a higher carriage rate of some key virulence genes than CSKP, suggesting region-specific evolutionary adaptations. Although CR-hvKP prevalence was lower than that of CS-hvKP, the persistent detection of key virulence genes in CRKP indicates ongoing dissemination risk, necessitating vigilant surveillance. Furthermore, the concurrent upregulation of two-component system genes (\n phoQ<\/jats:italic>\n ,\n rstA<\/jats:italic>\n , and\n ompR<\/jats:italic>\n ) in hypervirulent clinical isolates represents a phenotypic signature worthy of further mechanistic exploration.\n <\/jats:p>\n <\/jats:sec>\n <\/jats:sec>","DOI":"10.1128\/spectrum.02030-25","type":"journal-article","created":{"date-parts":[[2026,5,26]],"date-time":"2026-05-26T13:00:26Z","timestamp":1779800426000},"update-policy":"https:\/\/doi.org\/10.1128\/asmj-crossmark-policy-page","source":"Crossref","is-referenced-by-count":1,"title":["Comparative analysis of virulence factors and two-component systems expression in carbapenem-resistant and carbapenem-susceptible\n Klebsiella pneumoniae<\/i>\n isolates at a tertiary hospital in Wenzhou, China"],"prefix":"10.1128","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0009-0006-8444-9914","authenticated-orcid":true,"given":"Hao","family":"Chen","sequence":"first","affiliation":[{"id":[{"id":"https:\/\/ror.org\/0156rhd17","id-type":"ROR","asserted-by":"publisher"}],"name":"The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University","place":["Wenzhou, China"]},{"id":[{"id":"https:\/\/ror.org\/00rd5t069","id-type":"ROR","asserted-by":"publisher"}],"name":"The Second Clinical College of Wenzhou Medical University","place":["Wenzhou, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Peng","family":"Liu","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/042v6xz23","id-type":"ROR","asserted-by":"publisher"}],"name":"Department of Clinical Laboratory, The First Affiliated Hospital of Nanchang University","place":["Nanchang, 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