Epidemiological and Antimicrobial Resistance Trends of Klebsiella Pneumoniae Pre-, During, and Post-COVID-19 Pandemic in a Teaching Hospital in Southwest China

Lijun Du,1– 3 Yuan Jiang,2 Yueshuai Wei,2 Luting Shu,2 Zhangrui Zeng,2 Jinbo Liu1,2 1The First Clinical Medical College of Jinan University, Guangzhou, People’s Republic of China; 2Department of Laboratory Medicine, The Affiliated Hospital of Southwest Medical University, Sichuan Province Engineering Technology Research Center of Molecular Diagnosis of Clinical Diseases, Molecular Diagnosis of Clinical Diseases Key Laboratory of Luzhou, Luzhou, People’s Republic of China; 3Department of Clinical Laboratory, Beijing Anzhen Nanchong Hospital of Capital Medical University & Nanchong Central Hospital, The Affiliated Nanchong Central Hospital of North Sichuan Medical College, Nanchong, People’s Republic of ChinaCorrespondence: Zhangrui Zeng, Department of Laboratory Medicine, the Affiliated Hospital of Southwest Medical University, Sichuan Province Engineering Technology Research Center of Molecular Diagnosis of Clinical Diseases, Molecular Diagnosis of Clinical Diseases Key Laboratory of Luzhou, Luzhou, People’s Republic of China, Email [email protected] Jinbo Liu, Department of Laboratory Medicine, the Affiliated Hospital of Southwest Medical University, Sichuan Province Engineering Technology Research Center of Molecular Diagnosis of Clinical Diseases, Molecular Diagnosis of Clinical Diseases Key Laboratory of Luzhou, Luzhou, People’s Republic of China, Email [email protected]: To quantify phase-specific changes in antimicrobial resistance (AMR) of Klebsiella pneumoniae and carbapenem-resistant Klebsiella pneumoniae (CRKP) across the pre-, during, and post-pandemic phases to inform post-pandemic antimicrobial stewardship and infection prevention and control (IPC).Patients and Methods: We performed a retrospective study at a tertiary hospital in Southwest China (2018– 2024), quantifying AMR and isolate distribution by patient age, sex, specimen type, and clinical department for Klebsiella pneumoniae and CRKP across the pre-, during, and post-pandemic phases.Results: We identified 7073 non-duplicate Klebsiella pneumoniae isolates; CRKP comprised 4.9%. Among patients aged < 18 years, the Klebsiella pneumoniae isolation rate declined during the pandemic and rebounded in the post-pandemic phase (P < 0.001), mirroring the trend in blood specimens (P < 0.05). In contrast, isolation rates of Klebsiella pneumoniae and CRKP rose during and post-pandemic among patients aged ≥ 65 years, in sputum, and in intensive care units (ICUs) and respiratory department (P < 0.05). Resistance to ceftazidime in Klebsiella pneumoniae decreased from 25.3% pre-pandemic to 16.2% during the pandemic and rebounded to 19.9% in the post-pandemic (P < 0.001). Similar decrease–rebound trends were observed for other cephalosporins, β-lactam/β-lactamase inhibitor combinations, carbapenems, monobactams, and aminoglycosides (P < 0.05). Notably, fluoroquinolone resistance rose steadily during the pandemic and post-pandemic phases (P < 0.001). Among CRKP isolates, resistance to fluoroquinolones, aminoglycosides, and monobactams increased from 70.0%, 75.0%, and 90.0% in 2018 to 94.9%, 90.8%, and 96.9% in 2024, respectively.Conclusion: Klebsiella pneumoniae resistance temporarily declined during the pandemic but rebounded in the post-pandemic phase, whereas fluoroquinolone resistance continued to rise throughout. In the post-pandemic phase, CRKP exhibited markedly elevated resistance to aminoglycosides, fluoroquinolones, and monobactams, highlighting the urgent need for sustained AMR surveillance, AMS, and targeted IPC in the post-COVID-19 era.Keywords: Klebsiella pneumoniae, carbapenem-resistant Klebsiella pneumoniae, antimicrobial resistance, multidrug-resistant bacteria, COVID-19