Insertion sequences accelerate genomic convergence of multidrug resistance and hypervirulence in Klebsiella pneumoniae via capsular phase variation
Abstract Background The convergence of resistance and hypervirulence in Klebsiella pneumoniae represents a significant public health threat, driven by the horizontal transfer of plasmids. Understanding factors affecting plasmid transfer efficiency is essential to elucidate mechanisms behind emergenc...
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BMC
2025-05-01
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| Series: | Genome Medicine |
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| Online Access: | https://doi.org/10.1186/s13073-025-01474-0 |
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| author | Da-Wei Wei Yuqin Song Yi Li Gang Zhang Qi Chen Linhuan Wu Jiangqing Huang Xueru Tian Chao Wang Jie Feng |
| author_facet | Da-Wei Wei Yuqin Song Yi Li Gang Zhang Qi Chen Linhuan Wu Jiangqing Huang Xueru Tian Chao Wang Jie Feng |
| author_sort | Da-Wei Wei |
| collection | DOAJ |
| description | Abstract Background The convergence of resistance and hypervirulence in Klebsiella pneumoniae represents a significant public health threat, driven by the horizontal transfer of plasmids. Understanding factors affecting plasmid transfer efficiency is essential to elucidate mechanisms behind emergence of these formidable pathogens. Methods Hypermucoviscous K. pneumoniae strains were serially passaged in LB medium to investigate capsule-deficient phenotypes. Capsule-deficient mutants were analyzed using genetic sequencing to identify the types and insertion sites of insertion sequences (IS). Bioinformatics and statistical analyses based on the NCBI and National Microbiology Data Center (NMDC) database were used to map the origins and locations of IS elements. Conjugation assays were performed to assess plasmid transfer efficiency between encapsulated and capsule-deficient strains. A murine intestinal colonization model was employed to evaluate virulence levels and IS excision-mediated capsule restoration. Results Our research revealed that a hypervirulent K. pneumoniae (hvKP) strain acquired a bla NDM-1-bearing IncX3 plasmid with IS5 and ISKox3 elements. These IS elements are capable of inserting into capsular polysaccharide synthesis genes, causing a notably high frequency of capsule loss in vitro. The IS-mediated capsular phase variation, whether occurring in the donor or recipient strain, significantly increased the conjugation frequency of both the resistance plasmid and the virulence plasmid. Additionally, capsular phase variation enhanced bacterial adaptability in vitro. Experiments in mouse models demonstrated that capsule-deficient mutants exhibited reduced virulence and colonization capacity. However, during long-term intestinal colonization, IS element excision restored capsule expression, leading to the recovery of hypervirulence and enhanced colonization efficiency. Conclusions Our findings reveal that IS elements mediate capsular phase variation by toggling gene activity, accelerating the genomic convergence of multidrug resistance and hypervirulence in K. pneumoniae, as well as facilitating adaptive transitions in different environments. |
| format | Article |
| id | doaj-art-86e8d4f1b8984e808b8345237e0b91f3 |
| institution | Kabale University |
| issn | 1756-994X |
| language | English |
| publishDate | 2025-05-01 |
| publisher | BMC |
| record_format | Article |
| series | Genome Medicine |
| spelling | doaj-art-86e8d4f1b8984e808b8345237e0b91f32025-08-20T03:52:55ZengBMCGenome Medicine1756-994X2025-05-0117111310.1186/s13073-025-01474-0Insertion sequences accelerate genomic convergence of multidrug resistance and hypervirulence in Klebsiella pneumoniae via capsular phase variationDa-Wei Wei0Yuqin Song1Yi Li2Gang Zhang3Qi Chen4Linhuan Wu5Jiangqing Huang6Xueru Tian7Chao Wang8Jie Feng9State Key Laboratory of Microbial Diversity and Innovative Utilization, Institute of Microbiology, Chinese Academy of SciencesState Key Laboratory of Microbial Diversity and Innovative Utilization, Institute of Microbiology, Chinese Academy of SciencesState Key Laboratory of Microbial Diversity and Innovative Utilization, Institute of Microbiology, Chinese Academy of SciencesState Key Laboratory of Microbial Diversity and Innovative Utilization, Institute of Microbiology, Chinese Academy of SciencesState Key Laboratory of Microbial Diversity and Innovative Utilization, Institute of Microbiology, Chinese Academy of SciencesState Key Laboratory of Microbial Diversity and Innovative Utilization, Institute of Microbiology, Chinese Academy of SciencesState Key Laboratory of Microbial Diversity and Innovative Utilization, Institute of Microbiology, Chinese Academy of SciencesState Key Laboratory of Microbial Diversity and Innovative Utilization, Institute of Microbiology, Chinese Academy of SciencesState Key Laboratory of Microbial Diversity and Innovative Utilization, Institute of Microbiology, Chinese Academy of SciencesState Key Laboratory of Microbial Diversity and Innovative Utilization, Institute of Microbiology, Chinese Academy of SciencesAbstract Background The convergence of resistance and hypervirulence in Klebsiella pneumoniae represents a significant public health threat, driven by the horizontal transfer of plasmids. Understanding factors affecting plasmid transfer efficiency is essential to elucidate mechanisms behind emergence of these formidable pathogens. Methods Hypermucoviscous K. pneumoniae strains were serially passaged in LB medium to investigate capsule-deficient phenotypes. Capsule-deficient mutants were analyzed using genetic sequencing to identify the types and insertion sites of insertion sequences (IS). Bioinformatics and statistical analyses based on the NCBI and National Microbiology Data Center (NMDC) database were used to map the origins and locations of IS elements. Conjugation assays were performed to assess plasmid transfer efficiency between encapsulated and capsule-deficient strains. A murine intestinal colonization model was employed to evaluate virulence levels and IS excision-mediated capsule restoration. Results Our research revealed that a hypervirulent K. pneumoniae (hvKP) strain acquired a bla NDM-1-bearing IncX3 plasmid with IS5 and ISKox3 elements. These IS elements are capable of inserting into capsular polysaccharide synthesis genes, causing a notably high frequency of capsule loss in vitro. The IS-mediated capsular phase variation, whether occurring in the donor or recipient strain, significantly increased the conjugation frequency of both the resistance plasmid and the virulence plasmid. Additionally, capsular phase variation enhanced bacterial adaptability in vitro. Experiments in mouse models demonstrated that capsule-deficient mutants exhibited reduced virulence and colonization capacity. However, during long-term intestinal colonization, IS element excision restored capsule expression, leading to the recovery of hypervirulence and enhanced colonization efficiency. Conclusions Our findings reveal that IS elements mediate capsular phase variation by toggling gene activity, accelerating the genomic convergence of multidrug resistance and hypervirulence in K. pneumoniae, as well as facilitating adaptive transitions in different environments.https://doi.org/10.1186/s13073-025-01474-0Carbapenem-resistant hypervirulent Klebsiella pneumoniaeInsertion sequenceCapsular phase variationGenomic convergence |
| spellingShingle | Da-Wei Wei Yuqin Song Yi Li Gang Zhang Qi Chen Linhuan Wu Jiangqing Huang Xueru Tian Chao Wang Jie Feng Insertion sequences accelerate genomic convergence of multidrug resistance and hypervirulence in Klebsiella pneumoniae via capsular phase variation Genome Medicine Carbapenem-resistant hypervirulent Klebsiella pneumoniae Insertion sequence Capsular phase variation Genomic convergence |
| title | Insertion sequences accelerate genomic convergence of multidrug resistance and hypervirulence in Klebsiella pneumoniae via capsular phase variation |
| title_full | Insertion sequences accelerate genomic convergence of multidrug resistance and hypervirulence in Klebsiella pneumoniae via capsular phase variation |
| title_fullStr | Insertion sequences accelerate genomic convergence of multidrug resistance and hypervirulence in Klebsiella pneumoniae via capsular phase variation |
| title_full_unstemmed | Insertion sequences accelerate genomic convergence of multidrug resistance and hypervirulence in Klebsiella pneumoniae via capsular phase variation |
| title_short | Insertion sequences accelerate genomic convergence of multidrug resistance and hypervirulence in Klebsiella pneumoniae via capsular phase variation |
| title_sort | insertion sequences accelerate genomic convergence of multidrug resistance and hypervirulence in klebsiella pneumoniae via capsular phase variation |
| topic | Carbapenem-resistant hypervirulent Klebsiella pneumoniae Insertion sequence Capsular phase variation Genomic convergence |
| url | https://doi.org/10.1186/s13073-025-01474-0 |
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