Biological and genetic characteristics of three hypervirulent Klebsiella pneumoniae strains causing liver abscess

Yuqi ZHANG; Juan WANG; Lei HAN; Pu LI; Wentao MA; Chun ZHANG; Yali LI; Jing YUAN; Jin’e LEI

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Biological and genetic characteristics of three hypervirulent Klebsiella pneumoniae strains causing liver abscess

VernacularTitle:三株致肝脓肿高毒力肺炎克雷伯菌的生物学特性及基因特征分析
Author: Yuqi ZHANG ¹ ; Juan WANG ² ; Lei HAN ³ ; Pu LI ⁴ ; Wentao MA ² ; Chun ZHANG ⁵ ; Yali LI ⁶ ; Jing YUAN ⁶ ; Jin’e LEI ⁶
Author Information

1. Department of Laboratory Medicine, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an 710061; College of Veterinary Medicine, Northwest A&F University, Yangling 712100
2. College of Veterinary Medicine, Northwest A&F University, Yangling 712100
3. Department of Microbiology and Immunology, School of Basic Medicine, Xi’an Jiaotong University Health Science Center, Xi’an 710061
4. Department of Critical Care Medicine, The Second Affiliated Hospital of Air Force Medical University, Xi’an 710038
5. Surgical Intensive Care Unit, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an 710061, China
6. Department of Laboratory Medicine, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an 710061
Publication Type:Journal Article
Keywords: hypervirulent Klebsiella pneumoniae (hvKp); whole genome sequencing; drug resistance; high-virulence strain; mouse infection model
From: Journal of Xi'an Jiaotong University(Medical Sciences) 2024;45(6):885-894
CountryChina
Language:Chinese
Abstract: [Objective] To understand the resistance mechanisms, virulence characteristics, and pathogenicity of hypervirulent Klebsiella pneumoniae (hvKp), which causes pyogenic liver abscess (PLA), and to provide related data for clinical treatment of infection caused by this type of bacteria. [Methods] We collected three strains of Klebsiella pneumoniae isolated from the liver abscess fluid of patients with liver abscesses in various departments of The First Affiliated Hospital of Xi’an Jiaotong University. The hypervirulent phenotypes were determined by the wire test, and drug sensitivity was assessed using the VITEK 2 compact automatic microbiological analyzer. Molecular characteristics such as podocarp serotypes, multi-locus sequence typing (MLST), virulence genes, and drug resistance genes were identified through whole-genome sequencing. Additionally, a mouse infection model was established to evaluate pathogenicity. [Results] The isolates were sticky, with mucous thread pulling length >5 mm, all of which exhibited high viscosity phenotypes. Except 146007, which is a multidrug-resistant bacterium, the other two strains had higher antibiotic sensitivity. Whole genome sequencing revealed that the isolates were of high-virulence type, carrying the toxin plasmid rmpADC/rmpA2, iron uptake system, bacterial hairs, secretion system, and other virulence factors. All the three isolates tested positive for rmpA/rmpA2 combined with iucA/iutA, indicating they could be classified as hvKp. Multiple resistance genes were detected, such as β-lactamase like blaTEM, blaSHV, and blaCTX-M. The isolates were highly pathogenic to mice, as evidenced by the diseased organs of the deceased mice observed on autopsy. [Conclusion] The three strains of hvKp isolated in this study carried multiple drug-resistant genes and were highly pathogenic, which suggests that in laboratories and clinical practices it is imperative to promptly identify and adopt necessary disposal strategies to prevent further spread of hvKp.