Work

Acquisition, co-option, and duplication of the rtx toxin system and the emergence of virulence in Kingella

Year: 2022

Type: preprint

Abstract: The Kingella genus includes two pathogenic species, namely K. kingae and K. negevensis , as well as strictly commensal species. Both K. kingae and K. negevensis secrete a toxin called RtxA that is absent in the commensal species. Phylogenetic analysis demonstrates that the toxin-encoding operon rtxCrtxAtolC was acquired by a common ancestor of the pathogenic Kingella species and that a preexisting type I secretion system was co-opted for toxin export. Subsequent genomic reorganization distributed the toxin machinery across two loci, with 30-35% of K. kingae strains containing two copies of the rtxA toxin gene. The rtxA duplication is largely clonal and strongly associated with invasive disease. In assays with isogenic strains, a single copy of rtxA was associated with reduced virulence in vitro . This study establishes the critical steps in the evolutionary transition from commensal to pathogen, including horizontal gene transfer, co-option of an existing secretion system, and gene duplication.

Source: bioRxiv (Cold Spring Harbor Laboratory)

DOI: 10.1101/2022.11.28.518221

Authors: Daniel P. Morreale, Eric A. Porsch, Brad K. Kern, Joseph W. St Geme, Paul J. Planet

Institutions: Children's Hospital of Philadelphia, University of Pennsylvania, American Museum of Natural History

Language: English

Topic: Bacterial Infections and Vaccines

Subfield: Microbiology

Field: Immunology and Microbiology

Domain: Life Sciences

SDG: Good health and well-being

Open Access status: green

Funders: U.S. Department of Health and Human Services, Children's Hospital of Philadelphia, National Institute of Allergy and Infectious Diseases