{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,12]],"date-time":"2026-08-12T09:27:11Z","timestamp":1786526831442,"version":"build-2736575974"},"reference-count":30,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2026,8,12]],"date-time":"2026-08-12T00:00:00Z","timestamp":1786492800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Antibiotics"],"abstract":"<jats:p>Background:\u00a0Klebsiella pneumoniae is a leading cause of healthcare-associated infections and a major vehicle for the dissemination of antimicrobial resistance (AMR). Romania ranks among the most affected European countries for carbapenem-resistant K. pneumoniae (CRKP), yet data from specialized pulmonology\u2013critical care settings remain limited. Objective: This study aimed to characterize the antimicrobial resistance profiles of K. pneumoniae clinical isolates\u2014including MDR\/XDR\/PDR classification, carbapenem and colistin resistance rates, specimen and ward distribution, and category-specific resistance patterns\u2014at a tertiary pulmonology\u2013critical care institution in Bucharest, Romania. Methods: A retrospective, single-centre analysis of 203 K. pneumoniae clinical isolates from critical patients, which were collected at the Institute of Pneumology Marius Nasta, Bucharest, between July 2021 and May 2026. Susceptibility testing was performed using the VITEK\u00ae2 system (bioM\u00e9rieux), with results interpreted per EUCAST breakpoints. Results: Of 203 isolates, 112 (55.2%) were PDR, 36 (17.7%) XDR, six (3.0%) MDR, and 49 (24.1%) non-MDR. Carbapenem resistance was present in 134 isolates (66.0%); colistin resistance was present in 49 of 73 isolates tested (67.1%). Bronchial\/tracheal aspirate was the dominant specimen source (61.1%), and intensive care units accounted for 61.1% of isolates. Resistance rates exceeded 75% for monobactams, first\/second-generation cephalosporins, and fluoroquinolones. Conclusions: This cohort demonstrates severe AMR burden in this setting, consistent with the most concerning reports for K. pneumoniae in the literature. The findings underscore the urgent need for enhanced antimicrobial stewardship, strengthened infection control in ICU settings, and molecular surveillance of carbapenemase-producing high-risk clonal lineages in Romanian tertiary care.<\/jats:p>","DOI":"10.3390\/antibiotics15080774","type":"journal-article","created":{"date-parts":[[2026,8,12]],"date-time":"2026-08-12T07:57:26Z","timestamp":1786521446000},"page":"774","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Antimicrobial Resistance Profile of Klebsiella pneumoniae Clinical Isolates at a Tertiary Pulmonology-Critical Care Centre in Romania: A Five-Year Retrospective Study (2021\u20132026)"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8694-6195","authenticated-orcid":false,"given":"Loredana Sabina Cornelia","family":"Manolescu","sequence":"first","affiliation":[{"name":"Department of Microbiology, Parasitology and Virology, Faculty of Nursing, Carol Davila University of Medicine and Pharmacy, 020021 Bucharest, Romania"},{"name":"Clinical Laboratory of Medical Microbiology, Marius Nasta Institute of Pneumology, 050159 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5927-7069","authenticated-orcid":false,"given":"Madalina","family":"Solomon","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Parasitology and Virology, Faculty of Nursing, Carol Davila University of Medicine and Pharmacy, 020021 Bucharest, Romania"},{"name":"Clinical Laboratory of Medical Microbiology, Marius Nasta Institute of Pneumology, 050159 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Oana","family":"Popescu","sequence":"additional","affiliation":[{"name":"National Reference Laboratory of Tuberculosis, Marius Nasta Institute of Pneumology, 050159 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9240-922X","authenticated-orcid":false,"given":"Beatrice","family":"Mahler","sequence":"additional","affiliation":[{"name":"Cardiothoracic Department, Faculty of Medicine, Carol Davila University of Medicine and Pharmacy, 020956 Bucharest, Romania"},{"name":"1st Pneumology Department, Marius Nasta Institute of Pneumology, 050159 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9122-6862","authenticated-orcid":false,"given":"Dragos-Cosmin","family":"Zaharia","sequence":"additional","affiliation":[{"name":"3rd Pulmonology Section, 4th Department\u2014Cardio-Thoracic Pathology, Carol Davila University of Medicine and Pharmacy, 020021 Bucharest, Romania"},{"name":"7th Pulmonology Department, Marius Nasta Institute of Pneumology, 050159 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"131","DOI":"10.1016\/j.mib.2018.04.004","article-title":"Klebsiella pneumoniae as a Key Trafficker of Drug Resistance Genes from Environmental to Clinically Important Bacteria","volume":"45","author":"Wyres","year":"2018","journal-title":"Curr. Opin. Microbiol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"527","DOI":"10.1007\/s00203-026-05101-3","article-title":"Emergence of Gene Associations in High-Risk K. pneumoniae Clones: blaNDM-1 + blaOXA-48-like in ST15 and blaVIM + blaNDM-1 in ST405","volume":"208","author":"Raddaoui","year":"2026","journal-title":"Arch. Microbiol."},{"key":"ref_3","first-page":"e111986","article-title":"Burden of Difficult-to-Treat Resistant Organisms in Gram-Negative Bloodstream Infections: A Retrospective Observational Study from Eastern India","volume":"18","author":"Poddar","year":"2026","journal-title":"Cureus"},{"key":"ref_4","unstructured":"Antimicrobial Resistance Collaborators (2022). Global Burden of Bacterial Antimicrobial Resistance in 2019: A Systematic Analysis. Lancet, 399, 629\u2013655."},{"key":"ref_5","unstructured":"World Health Organization (2024). WHO Bacterial Priority Pathogens List, 2024: Bacterial Pathogens of Public Health Importance to Guide Research, Development and Strategies to Prevent and Control Antimicrobial Resistance."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"268","DOI":"10.1111\/j.1469-0691.2011.03570.x","article-title":"Multidrug-Resistant, Extensively Drug-Resistant and Pandrug-Resistant Bacteria: An International Expert Proposal for Interim Standard Definitions for Acquired Resistance","volume":"18","author":"Magiorakos","year":"2012","journal-title":"Clin. Microbiol. Infect."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Rezzoug, I., Vanparis, O., Poiraud, J., Nandakumaran, S., Girlich, D., Latour, L., Defoi, H., Emeraud, C., Jousset, A.B., and Birer, A. (2026). Carbapenemase-Producing Klebsiella oxytoca Complex in France (2017\u20132023): Molecular Epidemiology Integrated with Virulence and Biofilm Phenotypes. Emerg. Microbes Infect., 2713319.","DOI":"10.1080\/22221751.2026.2713319"},{"key":"ref_8","unstructured":"European Centre for Disease Prevention and Control (ECDC) (2025). Antimicrobial Resistance in the EU\/EEA (EARS-Net)\u2014Annual Epidemiological Report for 2024."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"T\u0103l\u0103pan, D., Dan, M.-O., Cire\u015f\u0103, A., and Rafila, A. (2026). Insights into Klebsiella pneumoniae Carbapenem Resistance\u2014A Two-Year Retrospective Study from a Romanian Tertiary Care Hospital. Front. Microbiol., 16.","DOI":"10.3389\/fmicb.2025.1728843"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Lazar, D.S., Nica, M., Oprisan, C., Vlasie, M., Condurache, I.-A., Florescu, S.A., and Gherlan, G.S. (2025). Emergence of Carbapenem-Resistant Klebsiella pneumoniae in a Romanian Infectious Diseases Hospital. Pathogens, 14.","DOI":"10.3390\/pathogens14090859"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Melinte, V., Radu, M.A., V\u0103c\u0103roiu, M.C., M\u00eerzan, L., Holban, T.S., Ileanu, B.V., Cismaru, I.M., and Gheorghi\u021b\u0103, V. (2025). Epidemiology of Carbapenem-Resistant Klebsiella pneumoniae Co-Producing MBL and OXA-48-Like in a Romanian Tertiary Hospital: A Call to Action. Antibiotics, 14.","DOI":"10.3390\/antibiotics14080783"},{"key":"ref_12","first-page":"e111794","article-title":"Emergence of Colistin Resistance in Multidrug-Resistant Escherichia coli and Klebsiella Species from Central India: A Sentinel Study with the Detection of Mcr-1 from Blood Isolates","volume":"18","author":"Kumari","year":"2026","journal-title":"Cureus"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Uzairue, L.I., Rabaan, A.A., Adewumi, F.A., Okolie, O.J., Folorunso, J.B., Bakhrebah, M.A., Garout, M., Alfouzan, W.A., Halwani, M.A., and Alamri, A.A. (2022). Global Prevalence of Colistin Resistance in Klebsiella pneumoniae from Bloodstream Infection: A Systematic Review and Meta-Analysis. Pathogens, 11.","DOI":"10.3390\/pathogens11101092"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Popivanov, G., Markovska, R., Gergova, I., Konaktchieva, M., Cirocchi, R., Kjossev, K., and Mutafchiyski, V. (2024). An Intra-Hospital Spread of Colistin-Resistant K. pneumoniae Isolates\u2014Epidemiological, Clinical, and Genetic Analysis. Medicina, 60.","DOI":"10.20944\/preprints202401.2136.v1"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Markovska, R., Stankova, P., Popivanov, G., Gergova, I., Mihova, K., Mutafchiyski, V., and Boyanova, L. (2024). Emergence of blaNDM-5 and blaOXA-232 Positive Colistin- and Carbapenem-Resistant Klebsiella pneumoniae in a Bulgarian Hospital. Antibiotics, 13.","DOI":"10.3390\/antibiotics13070677"},{"key":"ref_16","unstructured":"The European Committee on Antimicrobial Susceptibility Testing (2026). Breakpoint Tables for Interpretation of MICs and Zone Diameters, The European Committee on Antimicrobial Susceptibility Testing."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Sava, M., Vintila, B.I., Bereanu, A.S., Fratila, A.M., and Codru, I.R. (2025). Lessons from Four Years (2021\u20132024) of Klebsiella pneumoniae Resistance Surveillance Epidemiological Trends in a Romanian Intensive Care Unit. Antibiotics, 14.","DOI":"10.3390\/antibiotics14080825"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"100246","DOI":"10.1016\/j.microb.2025.100246","article-title":"Carbapenem-Resistant Klebsiella pneumoniae: A Comprehensive Review of Phenotypic and Genotypic Methods for Detection","volume":"6","author":"Mohammadpour","year":"2025","journal-title":"Microbe"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Sava, M., Codru, I.R., Bereanu, A.S., Stoia, O., and Vintila, B.I. (2025). Resistance Dynamics in a Romanian Critical Care Unit: Four Years of ESKAPE Pathogen Surveillance. Medicina, 61.","DOI":"10.3390\/medicina61122114"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"2661","DOI":"10.3390\/microbiolres15040176","article-title":"Six-Year Epidemiologic Analysis of Antibiotic Resistance Patterns of Klebsiella pneumoniae Infections in a Tertiary Healthcare Center in Western Romania","volume":"15","author":"Hogea","year":"2024","journal-title":"Microbiol. Res."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Cheng, S., Tong, D., Zhao, Q., Xiao, B., Zhang, Y., and Gong, Y. (2026). Association between MDROs Colonization and Subsequent Infections in ICU Patients: A Retrospective Cohort Study. Front. Public Health, 14.","DOI":"10.3389\/fpubh.2026.1863334"},{"key":"ref_22","first-page":"227","article-title":"Antimicrobial Resistance to Klebsiella pneumoniae in a North Eastern Romanian Hospital","volume":"16","author":"Luchian","year":"2024","journal-title":"Rom. J. Oral Rehabil."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Ghenea, A.E., Cioboat\u0103, R., Droca\u015f, A.I., \u021aieranu, E.N., Vasile, C.M., Moro\u015fanu, A., \u021aieranu, C.G., Salan, A.-I., Popescu, M., and Turculeanu, A. (2021). Prevalence and Antimicrobial Resistance of Klebsiella Strains Isolated from a County Hospital in Romania. Antibiotics, 10.","DOI":"10.3390\/antibiotics10070868"},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"\u00c7apar, A., \u00d6zyi\u011fito\u011flu, D., Ba\u015fl\u0131lar, \u015e., Efil Erdo\u011fan, M., Balak, B., Do\u011fan, B.N., Hun Akta\u015f, \u00d6., and Korkmaz, E. (2026). Changes in Antimicrobial Resistance Patterns in Intensive Care Units Following the COVID-19 Pandemic: A 10-Year Retrospective Study from T\u00fcrkiye. Antibiotics, 15.","DOI":"10.3390\/antibiotics15070636"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"441","DOI":"10.1007\/s11274-026-05172-w","article-title":"Stratified Cumulative Antibiograms and Antimicrobial Resistance Trends among Hospitalized Patients in a Chinese Tertiary Hospital: A 7-Year Retrospective Study","volume":"42","author":"Yuan","year":"2026","journal-title":"World J. Microbiol. Biotechnol."},{"key":"ref_26","first-page":"407","article-title":"High Prevalence of Multidrug-Resistant Klebsiella pneumoniae in Pediatric Patients: A Retrospective Analysis","volume":"51","author":"Andrusca","year":"2025","journal-title":"Curr. Health Sci. J."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Huang, C., Li, X., Yang, Z., Xia, C., Zhao, X., and Yuan, J. (2026). Effects of Common Disinfectants on Biofilm Formation and Eradication in Klebsiella pneumoniae with Different Resistance Phenotypes. Front. Cell. Infect. Microbiol., 16.","DOI":"10.3389\/fcimb.2026.1873119"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1163","DOI":"10.17219\/acem\/211911","article-title":"Antibiotic Resistance and Molecular Characteristics of OXA-48-Producing Klebsiella pneumoniae Isolates from Northeastern Poland","volume":"35","author":"Sacha","year":"2026","journal-title":"Adv. Clin. Exp. Med."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1312","DOI":"10.1007\/s11033-026-12487-2","article-title":"High Prevalence of ESBL Encoding Genes in Enterobacterales Isolated from Hospital and Environmental Wastewater in Pakistan\u2014One Health Challenge","volume":"53","author":"Qamar","year":"2026","journal-title":"Mol. Biol. Rep."},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Li, F.-H., Zheng, M., Zhong, G.-M., He, X.-M., Hu, M.-Z., Kuang, X., Wu, J.-J., Li, C.-M., Wang, J.-N., and Zhou, X.-Y. (2026). Resistance Development in KPC-Producing Klebsiella pneumoniae under Ceftazidime\/Avibactam-Meropenem Pressure: KPC-2 \u03a9-Loop Mutations Attenuate Avibactam Efficacy. Microbiol. Spectr., e00356-26.","DOI":"10.1128\/spectrum.00356-26"}],"container-title":["Antibiotics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2079-6382\/15\/8\/774\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,12]],"date-time":"2026-08-12T08:28:26Z","timestamp":1786523306000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2079-6382\/15\/8\/774"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8,12]]},"references-count":30,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2026,8]]}},"alternative-id":["antibiotics15080774"],"URL":"https:\/\/doi.org\/10.3390\/antibiotics15080774","relation":{},"ISSN":["2079-6382"],"issn-type":[{"value":"2079-6382","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8,12]]}}}