{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T17:54:19Z","timestamp":1785434059099,"version":"3.56.0"},"reference-count":36,"publisher":"American Society for Microbiology","issue":"4","license":[{"start":{"date-parts":[[2026,4,7]],"date-time":"2026-04-07T00:00:00Z","timestamp":1775520000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,4,7]],"date-time":"2026-04-07T00:00:00Z","timestamp":1775520000000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.asm.org\/non-commercial-tdm-license"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["82172311, 82302574"],"award-info":[{"award-number":["82172311, 82302574"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"China Antimicrobial Surveillance Network","award":["2018QD100"],"award-info":[{"award-number":["2018QD100"]}]},{"name":"Shanghai Antimicrobial Surveillance Network","award":["3030231003"],"award-info":[{"award-number":["3030231003"]}]},{"DOI":"10.13039\/100017950","name":"Shanghai Municipal Health Commission","doi-asserted-by":"publisher","award":["20244Y0152"],"award-info":[{"award-number":["20244Y0152"]}],"id":[{"id":"10.13039\/100017950","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100017950","name":"Shanghai Municipal Health Commission","doi-asserted-by":"publisher","award":["20224Y0260"],"award-info":[{"award-number":["20224Y0260"]}],"id":[{"id":"10.13039\/100017950","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["journals.asm.org"],"crossmark-restriction":true},"short-container-title":["Microbiol Spectr"],"published-print":{"date-parts":[[2026,4,7]]},"abstract":"ABSTRACT<\/jats:title>\n \n \n \n KPC-producing\n Klebsiella pneumoniae<\/jats:italic>\n infections are a rising global health threat. The factors driving\n bla<\/jats:italic>\n KPC<\/jats:sub>\n mutations during treatment and their contribution to infection persistence remain unclear. This study characterized\n bla<\/jats:italic>\n KPC<\/jats:sub>\n evolution under reduced-dose ceftazidime-avibactam therapy for renal impairment, using 10 sequential\n K. pneumoniae<\/jats:italic>\n isolates (showing resistance shifts) collected from a single patient during a persistent infection. Antimicrobial susceptibility was determined by broth microdilution. Whole-genome sequencing was used to investigate\n bla<\/jats:italic>\n KPC<\/jats:sub>\n evolution. Time-kill assays assessed bactericidal and selective effects. Plasmid transformation and cloning assays validated\n bla<\/jats:italic>\n KPC<\/jats:sub>\n phenotypes. Four\n bla<\/jats:italic>\n KPC<\/jats:sub>\n subtypes (\n bla<\/jats:italic>\n KPC-2<\/jats:sub>\n ,\n bla<\/jats:italic>\n KPC-33<\/jats:sub>\n ,\n bla<\/jats:italic>\n KPC-71<\/jats:sub>\n , and\n bla<\/jats:italic>\n KPC-145<\/jats:sub>\n ) were identified. Functional validation confirmed that\n bla<\/jats:italic>\n KPC-2<\/jats:sub>\n conferred carbapenem resistance, while the three variants mediated ceftazidime-avibactam resistance. Tracing their evolutionary trajectory revealed seven sequential mutation events during dose-adjusted ceftazidime-avibactam and carbapenem therapy, ultimately yielding the four observed subtypes. These mutations appeared to accumulate stepwise from\n bla<\/jats:italic>\n KPC-2<\/jats:sub>\n to\n bla<\/jats:italic>\n KPC-33<\/jats:sub>\n (D179Y) and\n bla<\/jats:italic>\n KPC-145<\/jats:sub>\n (D179Y, T264A), which progressively increased ceftazidime-avibactam MICs. Molecular docking predicted variant-specific alterations in avibactam binding. Time-kill assays showed that 1\u00d7MIC\/sub-MIC ceftazidime\u2013avibactam suppressed but failed to eradicate the\n bla<\/jats:italic>\n KPC-2<\/jats:sub>\n -harboring isolate, potentially facilitating\n bla<\/jats:italic>\n KPC-2<\/jats:sub>\n evolution. Multiple\n bla<\/jats:italic>\n KPC<\/jats:sub>\n variants coexisted within the same specimen, indicating intra-host heterogeneity. These reversible\n bla<\/jats:italic>\n KPC<\/jats:sub>\n mutations disappeared after 8 days of combined imipenem and ceftazidime-avibactam therapy. Meropenem-vaborbactam, imipenem-relebactam, and aztreonam-avibactam showed\n in vitro<\/jats:italic>\n activity against both KPC- and KPC variant-producing isolates. In conclusion, suboptimal ceftazidime-avibactam exposure may promote sequential\n bla<\/jats:italic>\n KPC-2<\/jats:sub>\n mutations and intra-host variants coexistence, driving persistent infection. These findings highlight the urgent need for improved therapeutic strategies against KPC\/KPC variant-producing strains.\n <\/jats:p>\n <\/jats:sec>\n \n IMPORTANCE<\/jats:title>\n \n Klebsiella pneumoniae<\/jats:italic>\n , especially those producing KPC or KPC variant enzymes, represent a growing threat to global health due to limited treatment options and frequent therapeutic failure. The emergence of\n bla<\/jats:italic>\n KPC<\/jats:sub>\n mutations during treatment further complicates therapy, as these mutations can lead to shifts in resistance profiles. Understanding the patterns and driving factors behind\n bla<\/jats:italic>\n KPC<\/jats:sub>\n mutations is crucial for developing more effective treatment strategies. This study shows that dose reduction of ceftazidime-avibactam during treatment for renal impairment can promote potential stepwise mutations in\n bla<\/jats:italic>\n KPC<\/jats:sub>\n , leading to the emergence of multiple variants with corresponding resistance shifts. Moreover, insufficient ceftazidime-avibactam and carbapenems fail to eradicate the bacteria, allowing the coexistence of\n K. pneumoniae<\/jats:italic>\n subpopulations carrying distinct\n bla<\/jats:italic>\n KPC<\/jats:sub>\n variants within a single patient. The findings highlight the need for individualized treatment regimens and optimized dosing and combination strategies to limit the emergence and persistence of KPC variant-producing\n K. pneumoniae<\/jats:italic>\n during therapy.\n <\/jats:p>\n <\/jats:sec>","DOI":"10.1128\/spectrum.03308-25","type":"journal-article","created":{"date-parts":[[2026,2,20]],"date-time":"2026-02-20T14:00:15Z","timestamp":1771596015000},"update-policy":"https:\/\/doi.org\/10.1128\/asmj-crossmark-policy-page","source":"Crossref","is-referenced-by-count":0,"title":["Suboptimal ceftazidime-avibactam exposure drives sequential\n bla<\/i>\n KPC<\/sub>\n mutations and intra-host coexistence of\n Klebsiella pneumoniae<\/i>\n harboring distinct variants leading to persistent infection"],"prefix":"10.1128","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1119-1274","authenticated-orcid":true,"given":"Feng","family":"Yang","sequence":"first","affiliation":[{"id":[{"id":"https:\/\/ror.org\/013q1eq08","id-type":"ROR","asserted-by":"publisher"}],"name":"Institute of Antibiotics, Huashan Hospital, Fudan University","place":["Shanghai, China"]},{"id":[{"id":"https:\/\/ror.org\/013q1eq08","id-type":"ROR","asserted-by":"publisher"}],"name":"Department of Laboratory Medicine, Huadong Hospital, Fudan University","place":["Shanghai, China"]},{"name":"Joint Laboratory of Hospital & Enterprise for Pathogen Diagnosis of Drug-resistant Bacterial Infections and Innovative Drug R&D","place":["Shanghai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Weiwei","family":"Yang","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/013q1eq08","id-type":"ROR","asserted-by":"publisher"}],"name":"Institute of Antibiotics, Huashan Hospital, Fudan University","place":["Shanghai, China"]},{"name":"Joint Laboratory of Hospital & Enterprise for Pathogen Diagnosis of Drug-resistant Bacterial Infections and Innovative Drug R&D","place":["Shanghai, China"]},{"id":[{"id":"https:\/\/ror.org\/004bdz679","id-type":"ROR","asserted-by":"publisher"}],"name":"Key Laboratory of Clinical Pharmacology of Antibiotics, Ministry of Health","place":["Shanghai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jinghao","family":"Zhang","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/013q1eq08","id-type":"ROR","asserted-by":"publisher"}],"name":"Department of Laboratory Medicine, Huadong Hospital, Fudan University","place":["Shanghai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chengkang","family":"Tang","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/013q1eq08","id-type":"ROR","asserted-by":"publisher"}],"name":"Institute of Antibiotics, Huashan Hospital, Fudan University","place":["Shanghai, China"]},{"name":"Joint Laboratory of Hospital & Enterprise for Pathogen Diagnosis of Drug-resistant Bacterial Infections and Innovative Drug R&D","place":["Shanghai, China"]},{"id":[{"id":"https:\/\/ror.org\/004bdz679","id-type":"ROR","asserted-by":"publisher"}],"name":"Key Laboratory of Clinical Pharmacology of Antibiotics, Ministry of Health","place":["Shanghai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Li","family":"Ding","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/013q1eq08","id-type":"ROR","asserted-by":"publisher"}],"name":"Institute of Antibiotics, Huashan Hospital, Fudan University","place":["Shanghai, China"]},{"name":"Joint Laboratory of Hospital & Enterprise for Pathogen Diagnosis of Drug-resistant Bacterial Infections and Innovative Drug R&D","place":["Shanghai, China"]},{"id":[{"id":"https:\/\/ror.org\/004bdz679","id-type":"ROR","asserted-by":"publisher"}],"name":"Key Laboratory of Clinical Pharmacology of Antibiotics, Ministry of Health","place":["Shanghai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Siquan","family":"Shen","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/013q1eq08","id-type":"ROR","asserted-by":"publisher"}],"name":"Institute of Antibiotics, Huashan Hospital, Fudan University","place":["Shanghai, China"]},{"name":"Joint Laboratory of Hospital & Enterprise for Pathogen Diagnosis of Drug-resistant Bacterial Infections and Innovative Drug R&D","place":["Shanghai, China"]},{"id":[{"id":"https:\/\/ror.org\/004bdz679","id-type":"ROR","asserted-by":"publisher"}],"name":"Key Laboratory of Clinical Pharmacology of Antibiotics, Ministry of Health","place":["Shanghai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yanhao","family":"Zhou","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/013q1eq08","id-type":"ROR","asserted-by":"publisher"}],"name":"Institute of Antibiotics, Huashan Hospital, Fudan University","place":["Shanghai, China"]},{"name":"Joint Laboratory of Hospital & Enterprise for Pathogen Diagnosis of Drug-resistant Bacterial Infections and Innovative Drug R&D","place":["Shanghai, China"]},{"id":[{"id":"https:\/\/ror.org\/004bdz679","id-type":"ROR","asserted-by":"publisher"}],"name":"Key Laboratory of Clinical Pharmacology of Antibiotics, Ministry of Health","place":["Shanghai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hongyu","family":"Zhao","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/013q1eq08","id-type":"ROR","asserted-by":"publisher"}],"name":"Department of Respiratory and Critical Care Medicine, Huadong Hospital, Fudan University","place":["Shanghai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jiaojiao","family":"Zhou","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/013q1eq08","id-type":"ROR","asserted-by":"publisher"}],"name":"Department of Respiratory and Critical Care Medicine, Huadong Hospital, Fudan University","place":["Shanghai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4493-0619","authenticated-orcid":true,"given":"Fupin","family":"Hu","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/013q1eq08","id-type":"ROR","asserted-by":"publisher"}],"name":"Institute of Antibiotics, Huashan Hospital, Fudan University","place":["Shanghai, China"]},{"name":"Joint Laboratory of Hospital & Enterprise for Pathogen Diagnosis of Drug-resistant Bacterial Infections and Innovative Drug R&D","place":["Shanghai, China"]},{"id":[{"id":"https:\/\/ror.org\/004bdz679","id-type":"ROR","asserted-by":"publisher"}],"name":"Key Laboratory of Clinical Pharmacology of Antibiotics, Ministry of Health","place":["Shanghai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"235","reference":[{"key":"e_1_3_4_2_2","doi-asserted-by":"publisher","DOI":"10.1016\/S1473-3099(21)00399-6"},{"key":"e_1_3_4_3_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.drup.2024.101083"},{"key":"e_1_3_4_4_2","doi-asserted-by":"publisher","DOI":"10.1128\/cmr.00008-23"},{"key":"e_1_3_4_5_2","doi-asserted-by":"publisher","DOI":"10.3390\/antibiotics14020141"},{"key":"e_1_3_4_6_2","doi-asserted-by":"publisher","DOI":"10.1093\/cid\/ciae403"},{"key":"e_1_3_4_7_2","doi-asserted-by":"publisher","DOI":"10.1128\/aac.00447-22"},{"key":"e_1_3_4_8_2","doi-asserted-by":"publisher","DOI":"10.1128\/msystems.00184-25"},{"key":"e_1_3_4_9_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.02497-17"},{"key":"e_1_3_4_10_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.ijantimicag.2025.107521"},{"key":"e_1_3_4_11_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.cmi.2023.01.012"},{"key":"e_1_3_4_12_2","doi-asserted-by":"publisher","DOI":"10.1093\/cid\/ciaa1521"},{"key":"e_1_3_4_13_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.ijantimicag.2024.107265"},{"key":"e_1_3_4_14_2","doi-asserted-by":"publisher","DOI":"10.1128\/jcm.02245-21"},{"key":"e_1_3_4_15_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.cmi.2017.08.030"},{"key":"e_1_3_4_16_2","doi-asserted-by":"publisher","DOI":"10.1093\/ofid\/ofad046"},{"key":"e_1_3_4_17_2","doi-asserted-by":"publisher","DOI":"10.1128\/aac.02414-21"},{"key":"e_1_3_4_18_2","doi-asserted-by":"publisher","DOI":"10.1128\/spectrum.01714-21"},{"key":"e_1_3_4_19_2","doi-asserted-by":"publisher","DOI":"10.1080\/22221751.2024.2356146"},{"key":"e_1_3_4_20_2","doi-asserted-by":"publisher","DOI":"10.1128\/aac.01120-24"},{"key":"e_1_3_4_21_2","doi-asserted-by":"publisher","DOI":"10.1128\/CMR.00058-14"},{"key":"e_1_3_4_22_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.micres.2024.127701"},{"key":"e_1_3_4_23_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.drup.2023.101038"},{"key":"e_1_3_4_24_2","doi-asserted-by":"publisher","DOI":"10.1038\/s41467-025-60828-9"},{"key":"e_1_3_4_25_2","doi-asserted-by":"publisher","DOI":"10.1093\/jac\/dkaa283"},{"key":"e_1_3_4_26_2","volume-title":"Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically","author":"CLSI","year":"2024","unstructured":"CLSI. 2024. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically. 12th ed. Clinical and Laboratory Standards Institute, Wayne, PA.","edition":"12"},{"key":"e_1_3_4_27_2","volume-title":"Performance standards for antimicrobial susceptibility testing","author":"CLSI","year":"2025","unstructured":"CLSI. 2025. Performance standards for antimicrobial susceptibility testing. 35th ed. Clinical and Laboratory Standards Institute, Wayne, PA.","edition":"35"},{"key":"e_1_3_4_28_2","doi-asserted-by":"publisher","DOI":"10.1186\/2047-217X-1-18"},{"key":"e_1_3_4_29_2","doi-asserted-by":"publisher","DOI":"10.1093\/bioinformatics\/btu153"},{"key":"e_1_3_4_30_2","doi-asserted-by":"publisher","DOI":"10.1099\/mgen.0.000748"},{"key":"e_1_3_4_31_2","doi-asserted-by":"publisher","DOI":"10.1038\/s41467-021-24448-3"},{"key":"e_1_3_4_32_2","doi-asserted-by":"publisher","DOI":"10.1128\/AAC.02412-14"},{"key":"e_1_3_4_33_2","doi-asserted-by":"publisher","DOI":"10.1093\/bioinformatics\/btv421"},{"key":"e_1_3_4_34_2","doi-asserted-by":"publisher","DOI":"10.1093\/nar\/gku1196"},{"key":"e_1_3_4_35_2","doi-asserted-by":"publisher","DOI":"10.1093\/bioinformatics\/btz305"},{"key":"e_1_3_4_36_2","doi-asserted-by":"publisher","DOI":"10.1038\/s41586-024-07487-w"},{"key":"e_1_3_4_37_2","doi-asserted-by":"publisher","DOI":"10.1038\/s41401-019-0228-6"}],"container-title":["Microbiology Spectrum"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.asm.org\/doi\/pdf\/10.1128\/spectrum.03308-25","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.asm.org\/doi\/pdf\/10.1128\/spectrum.03308-25","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,4,7]],"date-time":"2026-04-07T13:07:48Z","timestamp":1775567268000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.asm.org\/doi\/10.1128\/spectrum.03308-25"}},"subtitle":[],"editor":[{"given":"Gabriele","family":"Arcari","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"editor"}]}],"short-title":[],"issued":{"date-parts":[[2026,4,7]]},"references-count":36,"journal-issue":{"issue":"4","published-print":{"date-parts":[[2026,4,7]]}},"alternative-id":["10.1128\/spectrum.03308-25"],"URL":"https:\/\/doi.org\/10.1128\/spectrum.03308-25","relation":{},"ISSN":["2165-0497"],"issn-type":[{"value":"2165-0497","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,4,7]]},"assertion":[{"value":"2025-10-15","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-12-22","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-02-20","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"e03308-25"}}