Higher Virulence Renders K2 Klebsiella pneumoniae a Stable Share Among Those from Pyogenic Liver Abscess

Abstract

Objective

To explore why serotype K2 accounts for a stable share in Klebsiella pneumoniae from pyogenic liver abscess (PLA).

Methods

Totally 15 K2 K. pneumoniae strains from PLA, 21 K2 from non-PLA, and 31 K1 from PLA were collected from China. Sequence typing, molecular serotyping, regular PCR, and Galleria mellonella lethality were performed. A total of 12 virulence genes were detected: peg-344, allS, p-rmpA, p-rmpA2, c-rmpA, fimH, mrkD, iucA, iroN, irp2, entB, and wzi. The differences between K2 K. pneumoniae strains from PLA and non-PLA were investigated along with K1 ones.

Results

Significant differences were found between K2 strains from PLA and non-PLA for the rates of virulence genes peg-344 and iucA. The latter group also showed more diverse sequence types than the former. Significant differences were only found for virulence genes allS and irp2 between K1 and K2 strains from PLA. Based on the equal virulence factors backgrounds other than serotypes, K2 strain is more virulent than K1 as G. mellonella lethality confirmed. Gene p-rmpA only brings equal virulence to p-rmpA plus p-rmpA2 in K2 strain.

Conclusion

Based on the same virulence factors backgrounds except serotypes, K2 K. pneumoniae is more virulent than K1 from PLA, which provides a survival advantage to maintain a stable share.

Keywords:

• Klebsiella pneumoniae
• pyogenic liver abscess
• serotype
• virulence
• gene

Data Availability

The authors confirm that the data supporting the findings of this study are available within the article and its supplementary materials.

Ethics Approval and Consent to Participate

The studies involving human participants were reviewed and approved by the Ethics Committee of Huashan Hospital (Shanghai, China) (ethical approval No. 2021-484). The consent for participation was waived for this study in accordance with the national legislation and the institutional requirements. As per Item No. 34 of Measures for Ethical Review of Biomedical Research Involving Human Beings (National Health and Family Planning Commission of China, 2014), the strains involved in this study belong to anonymous recorded materials and therefore the ethical approval was needed while consent for participation was waived. All the methods were carried out in accordance with relevant guidelines and regulations for the present study.

Acknowledgments

We thank such researchers for providing Klebsiella pneumoniae strains involved in this study: Professor Jin-Town Wang (Department of Internal Medicine, National Taiwan University Hospital), Professor Xiaofei Jiang (Department of Laboratory Medicine, Huashan Hospital, Fudan University), Gang Li (Department of Laboratory Medicine, Jinshan Hospital of Fudan University, Shanghai, China), Zehua Yang (Department of Laboratory Medicine, Sixth Hospital of Shanxi Medical University, Taiyuan, Shanxi, China), and Meng Li (Department of Clinical Laboratory, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China).

Author Contributions

All authors made a significant contribution to the work reported, whether that was in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

The authors report there are no competing interests to declare.

Additional information

Funding

The work was supported by the Natural Science Foundation of Gansu (21JR11RA209) and Zhejiang Provincial Health Commission under Grant Numbers 2023KY1326 and 2024KY535.