Prevalence of multidrug-resistant hypervirulent Klebsiella pneumoniae without defined hypervirulent biomarkers in Anhui, China: a new dimension of hypervirulence

Frontiers in Microbiology

Microbiology

Huaiwei Lu¹  Yuanyuan Dai¹  Yu Yang²  Baolin Sun³  Zhien He³  Md Roushan Ali³  Yujie Li³ 

[1] Department of Clinical Laboratory, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China;Department of Emergency Medicine, The Affiliated Provincial Hospital of Anhui Medical University, Hefei, Anhui, China;Department of Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China;

关键词: Klebsiella pneumoniae;    rmpA;    hypervirulence;    hypermucoviscosity;    virulence factors;    wzc;    whole genome sequencing;   

DOI  :  10.3389/fmicb.2023.1247091

 received in 2023-06-25, accepted in 2023-08-30,  发布年份 2023

来源: Frontiers

【 摘 要 】

Klebsiella pneumoniae is an opportunistic pathogen that mainly causes nosocomial infections and hospital-associated pneumonia in elderly and immunocompromised people. However, multidrug-resistant hypervirulent K. pneumoniae (MDR-hvKp) has emerged recently as a serious threat to global health that can infect both immunocompromised and healthy individuals. It is scientifically established that plasmid-mediated regulator of mucoid phenotype genes (rmpA and rmpA2) and other virulence factors (aerobactin and salmochelin) are mainly responsible for this phenotype. In this study, we collected 23 MDR-hvKp isolates and performed molecular typing, whole genome sequencing, comparative genomic analysis, and phenotypic experiments, including the Galleria mellonella infection model, to reveal its genetic and phenotypic features. Meanwhile, we discovered two MDR-hvKp isolates (22122315 and 22091569) that showed a wide range of hypervirulence and hypermucoviscosity without rmpA and rmpA2 and any virulence factors. In phenotypic experiments, isolate 22122315 showed the highest hypervirulence (infection model) with significant mucoviscosity, and conversely, isolate 22091569 exhibited the highest mucoviscosity (string test) with higher virulence compared to control. These two isolates carried carbapenemase (blaKPC − 2), β-lactamase (blaOXA − 1, blaTEM − 1B), extended-spectrum β-lactamase (ESBL) genes (blaCTX − M − 15, blaSHV − 106), outer membrane protein-coding genes (ompA), fimbriae encoding genes (ecpABCDER), and enterobactin coding genes (entAB, fepC). In addition, single nucleotide polymorphism analysis indicated that both isolates, 22122315 and 22091569, were found to have novel mutations in loci FEBNDAKP_03184 (c. 2084A > C, p. Asn695Thr), and EOFMAFIB_02276 (c. 1930C > A, p. Pro644Thr), respectively. Finally, NCBI blast analysis suggested these mutations are located in the wzc of the capsule polysaccharide (cps) region and are responsible for putative tyrosine kinase. This study would be a strong reference for enhancing the current understanding of identifying the MDR-hvKp isolates that lacked both mucoid regulators and virulence factors.

【 授权许可】

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Copyright © 2023 Ali, Yang, Dai, Lu, He, Li and Sun.