1. Temperatures above 37°C increase virulence of a convergent Klebsiella pneumoniae sequence type 307 strain.
- Author
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Müller JU, Schwabe M, Swiatek LS, Heiden SE, Schlüter R, Sittner M, Bohnert JA, Becker K, Idelevich EA, Guenther S, Eger E, and Schaufler K
- Subjects
- Virulence genetics, Animals, Larva microbiology, Plasmids genetics, Moths microbiology, Humans, Virulence Factors genetics, Bacterial Proteins genetics, Bacterial Proteins metabolism, Lepidoptera microbiology, Viscosity, Phenotype, Gene Expression Profiling, Klebsiella pneumoniae genetics, Klebsiella pneumoniae pathogenicity, Klebsiella pneumoniae classification, Biofilms growth & development, Klebsiella Infections microbiology, Temperature
- Abstract
Background: Convergence of Klebsiella pneumoniae (KP) pathotypes has been increasingly reported in recent years. These pathogens combine features of both multidrug-resistant and hypervirulent KP. However, clinically used indicators for hypervirulent KP identification, such as hypermucoviscosity, appear to be differentially expressed in convergent KP, potential outbreak clones are difficult to identify. We aimed to fill such knowledge gaps by investigating the temperature dependence of hypermucoviscosity and virulence in a convergent KP strain isolated during a clonal outbreak and belonging to the high-risk sequence type (ST)307., Methods: Hypermucoviscosity, biofilm formation, and mortality rates in Galleria mellonella larvae were examined at different temperatures (room temperature, 28°C, 37°C, 40°C and 42°C) and with various phenotypic experiments including electron microscopy. The underlying mechanisms of the phenotypic changes were explored via qPCR analysis to evaluate plasmid copy numbers, and transcriptomics., Results: Our results show a temperature-dependent switch above 37°C towards a hypermucoviscous phenotype, consistent with increased biofilm formation and in vivo mortality, possibly reflecting a bacterial response to fever-like conditions. Furthermore, we observed an increase in plasmid copy number for a hybrid plasmid harboring carbapenemase and rmpA genes. However, transcriptomic analysis revealed no changes in rmpA expression at higher temperatures, suggesting alternative regulatory pathways., Conclusion: This study not only elucidates the impact of elevated temperatures on hypermucoviscosity and virulence in convergent KP but also sheds light on previously unrecognized aspects of its adaptive behavior, underscoring its resilience to changing environments., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Müller, Schwabe, Swiatek, Heiden, Schlüter, Sittner, Bohnert, Becker, Idelevich, Guenther, Eger and Schaufler.)
- Published
- 2024
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