The Epidemiology, Virulence and Antimicrobial Resistance of Invasive Klebsiella pneumoniae at a Children’s Medical Center in Eastern China

Yang Li,1– 4,* Dan Li,5,* Jian Xue,4 Xueqiang Ji,4 Xuejun Shao,4 Jie Yan1– 3 1Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310003, People’s Republic of China; 2Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, People’s Republic of China; 3Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310003, People’s Republic of China; 4Department of Clinical Laboratory, Children’s Hospital of Soochow University, Suzhou, Jiangsu, 215025, People’s Republic of China; 5Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu, 215004, People’s Republic of China*These authors contributed equally to this workCorrespondence: Jie YanDepartment of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, 866 Yu-Hang-Tang Road, Hangzhou, Zhejiang, 310058, People’s Republic of ChinaTel +86-571-88208297Fax +86-571-88208294Email Med_bp@zju.edu.cnXuejun ShaoDepartment of Clinical Laboratory, Children’s Hospital of Soochow University, 92 Zhong-Nan Street, Suzhou, Jiangsu, 215025, People’s Republic of ChinaTel +86-512-80691203Email xjshao@suda.edu.cnObjective: This study investigated the epidemiology, virulence and drug resistance of invasive Klebsiella pneumoniae (K. pneumoniae) isolates at a children’s medical center in eastern China in order to obtain epidemiologic, virulence, and antimicrobial resistance data that can guide for the selection and development of anti-infection treatments.Methods: A total of 94 invasive K. pneumoniae strains were isolated from children between January 2016 and December 2020 at the Children’s Hospital of Soochow University. The strains were identified by mass spectrometry. The Kirby–Bauer method and VITEK 2 Compact system were used to analyze the antimicrobial susceptibility. Polymerase chain reaction (PCR) and sequencing was performed to detect the capsular serotypes, virulence-associated genes, β-lactam antibiotic resistance genes and multilocus sequence typing.Results: The PCR results showed that 87 strains (92.55%) of invasive K. pneumoniae were hypervirulent capsular serotypes, with K57 as the dominant capsular serotype (62.77%). All strains carried virulence-associated genes. Among them, 84 strains (89.36%) carried hypervirulence genes, with iroB (86.17%) being the predominant; meanwhile, other virulence genes, including wabG (100.00%), mrkD (98.94%), ycfM (96.81%), fimH (95.74%) and Uge (88.30%), were detected in most strains. All strains carried β-lactam antibiotic resistance genes; the main extended-spectrum β-lactamase gene was blaSHV-11 (86.17%) and the major AmpC cephalosporinase genes were blaFOX-1 (86.17%) and blaACT-1 (70.21%). Carbapenemase genes were detected in only a few isolates. Notably, 12 invasive K. pneumoniae isolates were identified as carbapenem-resistant and hypervirulent K. pneumoniae (CR-HVKP), and 14 other multidrug resistance (MDR) isolates were also detected.Conclusion: The results of this study reveal the epidemiology, virulence and antimicrobial resistance of invasive K. pneumoniae in pediatric patients. Both CR-HVKP and MDR strains were identified, which should be of great concern to clinicians.Keywords: Klebsiella pneumoniae, invasive infection, children, virulence factors, resistance genes