A troubling rise in severe invasive infections worldwide, which are becoming resistant to crucial antibiotics, has prompted a team of infectious disease researchers at the Houston Methodist Research Institute to investigate a new strain of bacteria known as Streptococcus dysgalactiae subspecies equisimilis (SDSE). This bacterium can cause infections that range from mild sore throats to serious flesh-eating diseases.
While it shares similarities with the well-researched group A streptococcus (also known as Streptococcus pyogenes), there is still much to learn about SDSE.
This research is detailed in a paper titled “Integrative genomic, virulence, and transcriptomic analysis of emergent Streptococcus dysgalactiae subspecies equisimilis (SDSE) emm type stG62647 isolates causing human infections,” which was published on October 17 in the journal mBio, issued by the American Society for Microbiology in collaboration with the American Academy of Microbiology. James M. Musser, M.D., Ph.D., who heads the Department of Pathology and Genomic Medicine at Houston Methodist, served as the corresponding author for the paper.
“It’s remarkable that despite its rising significance for public health, we still have limited knowledge about the molecular pathogenesis of SDSE,” remarked Jesus M. Eraso, Ph.D., an assistant research professor in pathology & genomic medicine at Houston Methodist and the study’s lead author.
To bridge this knowledge gap, the Houston Methodist team adopted a comprehensive approach to examine 120 human isolates from a specific subtype of SDSE, designated as stG62647. They studied the genome, which contains the DNA information, the transcriptome, offering a complete gene expression profile at the time the SDSE cells were gathered, and its virulence, which refers to the extent of harm it inflicts on its host. The stG62647 strains are particularly noteworthy as they have been linked to more severe infections, and analyzing the connections between these three aspects helped the researchers gain a deeper understanding of its disease-causing mechanisms.
The results from this integrative analysis provided valuable insights into this emerging human bacterial pathogen and will assist in vaccine research. Moreover, it raised several new inquiries and led to fresh hypotheses that need to be explored in this ongoing research endeavor.
Musser and Eraso collaborated with Randall J. Olsen, S. Wesley Long, and Ryan Gadd from the Center for Infectious Diseases at the Houston Methodist Research Institute, alongside Sarrah Boukthir, Ahmad Faili, and Samer Kayal from Université Rennes in France on this study.
This research was partially supported by the Fondren Foundation.
