The role of urease in the acid stress response and fimbriae expression in Klebsiella pneumoniae CG43

Wei-Feng Lin; Rong-Yu Hu; Hwan-You Chang; Fang-Yu Lin; Chih-Hao Kuo; Li-Hsin Su; Hwei-Ling Peng

doi:10.1016/j.jmii.2022.02.002

The role of urease in the acid stress response and fimbriae expression in Klebsiella pneumoniae CG43

J Microbiol Immunol Infect. 2022 Aug;55(4):620-633. doi: 10.1016/j.jmii.2022.02.002. Epub 2022 Mar 16.

Authors

Wei-Feng Lin¹, Rong-Yu Hu¹, Hwan-You Chang², Fang-Yu Lin², Chih-Hao Kuo³, Li-Hsin Su¹, Hwei-Ling Peng⁴

Affiliations

¹ Institute of Molecular Medicine and Bioengineering, National Yang Ming Chiao Tung University, Hsin Chu, Taiwan.
² Institute of Molecular Medicine, National Tsing Hua University, Hsin Chu, Taiwan.
³ Department of Biological Science and Technology, School of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsin Chu, Taiwan.
⁴ Institute of Molecular Medicine and Bioengineering, National Yang Ming Chiao Tung University, Hsin Chu, Taiwan; Department of Biological Science and Technology, School of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsin Chu, Taiwan. Electronic address: hlpeng@nycu.edu.tw.

PMID: 35367140
DOI: 10.1016/j.jmii.2022.02.002

Abstract

Background/purpose: Two urease operons were identified in Klebsiella pneumoniae CG43, ure-1 and ure-2. This study investigates whether a differential regulation of the expression of ure-1 and ure-2 exists and how urease activity influences the acid stress response and expression of type 1 and type 3 fimbriae.

Methods: The ureA1 and ureA2 gene specific deletion mutants were constructed. Promoter activity was assessed using a LacZ reporter system. The sensitivity to acid stress was determined by assessing the survival after pH 2.5 treatment. The influence on type 1 and type 3 fimbriae expression was assessed using western blotting and mannose-sensitive yeast agglutination and biofilm formation assay, respectively.

Results: Bacterial growth analysis in mM9-U or modified Stuart broth revealed that ure-1 was the principal urease system, and ure-2 had a negative effect on ure-1 activity. Deletion of the fur or nac gene had no apparent effect on the activity of P_ure1, P_ure2-1, and P_ure2-2. The P_ure2-2 activity was enhanced by deletion of the hns gene. ureA1 deletion increased acid stress sensitivity, whereas the deleting effect of ureA2 was notable without hns. Deletion of ureA1 or ureA2 significantly induced the expression of type 1 fimbriae but decreased MrkA production and biofilm formation.

Conclusion: ure-1 is the primary expression system in K. pneumoniae CG43, while ure-2 is active in the absence of hns. Impairment of urease activity increases the sensitivity to acid stress, and the accumulation of urea induces the expression of type 1 fimbriae but represses type 3 fimbriae expression.

Keywords: Acid stress response; Klebsiella pneumoniae CG43; Type 1 and type 3 fimbriae; Ure-1 and Ure-2 operons.

MeSH terms

Bacterial Proteins
Fimbriae, Bacterial
Gene Expression Regulation, Bacterial
Klebsiella pneumoniae*
Urease*

Substances

Bacterial Proteins
Urease