ORIGINAL RESEARCH article
Front. Microbiol.
Sec. Antimicrobials, Resistance and Chemotherapy
This article is part of the Research TopicMultidrug Resistant Gram-negative Bacteria in Fragile HostsView all 13 articles
Genomic characterization of Ceftazidime/avibactam-resistant Klebsiella pneumoniae: a retrospective analysis on clinical isolates from an Italian Transplant Unit
Provisionally accepted
Emanuele Nicitra1
MADDALENA CALVO2*
Ilenia Filannino1
Nicolò Musso3
Grete Francesca Privitera4
Davide Lo Porto5
Andrea Cona5Francesco Monaco5
Alessandra Mularoni5Stefania Stefani1
Dafne Bongiorno1*- 1Universita degli Studi di Catania Dipartimento di Scienze biomediche e biotecnologiche, Catania, Italy
- 2U.O.C. Laboratory Analysis Unit, A.O.U. “Policlinico-San Marco”, Via S. Sofia 78, Catania, 95123, Italy, Catania, Italy
- 3Universita degli Studi di Enna 'Kore', Enna, Italy
- 4Universita degli Studi di Catania Dipartimento di Medicina Clinica e Sperimentale, Catania, Italy
- 5Istituto Mediterraneo per i Trapianti e Terapie ad Alta Specializzazione, Palermo, Italy
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Abstract: Introduction. Klebsiella pneumoniae infections are a significant healthcare concern due to advancing antimicrobial resistance rates and virulence genes' detection. Specifically, ceftazidime/avibactam resistance increasingly diffused among K. pneumoniae clinical isolates, limiting therapeutical choices and complicating patients' outcomes. Some authors documented the simultaneous presence of ceftazidime/avibactam resistance markers and specific virulence genes. According to these premises, we characterized ceftazidime/avibactam-resistant K. pneumoniae strains, exploring their diffusion among the Mediterranean Institute for Transplants and Highly Specialized Therapies (ISMETT) of Palermo, Italy. Materials and methods. A total of 14 ceftazidime/avibactam-resistant strains were retrospectively analyzed using whole genome sequencing and Sanger validation. Results. Most strains belonged to ST101 and carried blaKPC-31, blaKPC-3, or blaKPC-34 genes, often with resistance-associated mutations. The analysed strains revealed multidrug resistance, frequent outer membrane protein alterations, and a significant spectrum of virulence genes. Additionally, plasmid analysis revealed sequence type–specific replicons potentially involved in gene dissemination. Discussion. These findings highlight a convergence of resistance and virulence traits in high-risk K. pneumoniae clones, enhancing the importance of MDR pathogens genomic surveillance within critical healthcare settings.
Keywords: antimicrobial resistance, Ceftazidime/ avibactam, Klebsiella pneumoniae, molecular characterization, resistome, Transplant unit, virulome
Received: 28 Aug 2025; Accepted: 13 Jan 2026.
Copyright: © 2026 Nicitra, CALVO, Filannino, Musso, Privitera, Lo Porto, Cona, Monaco, Mularoni, Stefani and Bongiorno. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
MADDALENA CALVO
Dafne Bongiorno
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