Investigating Anthrax-Associated Virulence Genes among Archival and Contemporary <i>Bacillus cereus</i> Group Genomes
Susanna J. Sabin,
Cari A. Beesley,
Chung K. Marston,
Taylor K. Paisie,
Christopher A. Gulvik,
Gregory A. Sprenger,
Jay E. Gee,
Rita M. Traxler,
Melissa E. Bell,
John R. McQuiston,
Zachary P. Weiner
Affiliations
Susanna J. Sabin
Laboratory Leadership Service Fellow Assigned to the National Center for Emerging and Zoonotic Infectious Diseases, CDC, Atlanta, GA 30329, USA
Cari A. Beesley
Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases, Division of High-Consequence Pathogens and Pathology, Bacterial Special Pathogens Branch, 1600 Clifton Rd, Atlanta, GA 30329, USA
Chung K. Marston
Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases, Division of High-Consequence Pathogens and Pathology, Bacterial Special Pathogens Branch, 1600 Clifton Rd, Atlanta, GA 30329, USA
Taylor K. Paisie
Oak Ridge Institute for Science and Education, Oak Ridge, TN 37830, USA
Christopher A. Gulvik
Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases, Division of High-Consequence Pathogens and Pathology, Bacterial Special Pathogens Branch, 1600 Clifton Rd, Atlanta, GA 30329, USA
Gregory A. Sprenger
Oak Ridge Institute for Science and Education, Oak Ridge, TN 37830, USA
Jay E. Gee
Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases, Division of High-Consequence Pathogens and Pathology, Bacterial Special Pathogens Branch, 1600 Clifton Rd, Atlanta, GA 30329, USA
Rita M. Traxler
Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases, Division of High-Consequence Pathogens and Pathology, Bacterial Special Pathogens Branch, 1600 Clifton Rd, Atlanta, GA 30329, USA
Melissa E. Bell
Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases, Division of High-Consequence Pathogens and Pathology, Bacterial Special Pathogens Branch, 1600 Clifton Rd, Atlanta, GA 30329, USA
John R. McQuiston
Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases, Division of High-Consequence Pathogens and Pathology, Bacterial Special Pathogens Branch, 1600 Clifton Rd, Atlanta, GA 30329, USA
Zachary P. Weiner
Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases, Division of High-Consequence Pathogens and Pathology, Bacterial Special Pathogens Branch, 1600 Clifton Rd, Atlanta, GA 30329, USA
Bacillus anthracis causes anthrax through virulence factors encoded on two plasmids. However, non-B. anthracis organisms within the closely related, environmentally ubiquitous Bacillus cereus group (BCG) may cause an anthrax-like disease in humans through the partial adoption of anthrax-associated virulence genes, challenging the definition of anthrax disease. To elucidate these phenomena and their evolutionary past, we performed whole-genome sequencing on non-anthracis BCG isolates, including 93 archival (1967–2003) and 5 contemporary isolates (2019–2023). We produced annotated genomic assemblies and performed a pan-genome analysis to identify evidence of virulence gene homology and virulence gene acquisition by linear inheritance or horizontal gene transfer. At least one anthrax-associated virulence gene was annotated in ten isolates. Most homologous sequences in archival isolates showed evidence of pseudogenization and subsequent gene loss. The presence or absence of accessory genes, including anthrax-associated virulence genes, aligned with the phylogenetic structure of the BCG core genome. These findings support the hypothesis that anthrax-associated virulence genes were inherited from a common ancestor in the BCG and were retained or lost across different lineages, and contribute to a growing body of work informing public health strategies related to anthrax surveillance and identification.
