Houston Methodist Cracks Bacterial Threat Code

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Scientists at Houston Methodist Research Institute have discovered that a fast-rising strep bacterium, Streptococcus dysgalactiae subspecies equisimilis (SDSE), comes in more forms than expected, including ones that may lead to life-threatening infections. Using whole-genome sequencing on over 800 patient samples, the researchers found 44 distinct variants of the bacterium, with certain strains associated with specific types of infections like skin, blood, and throat.

Why it matters

SDSE infections are increasing worldwide, and the bacterium is closely related to the flesh-eating Group A Strep, which can cause severe conditions like blood infections and necrotizing fasciitis. This new genetic data provides critical insights that can improve diagnosis, infection control, and future vaccine planning for these dangerous streptococcal infections.

The details

The study, led by James Musser, M.D., Ph.D., chair of the Department of Pathology and Genomic Medicine at Houston Methodist, is the largest U.S. investigation of SDSE to date. First author Lydia Pouga, Ph.D., a research scientist at Houston Methodist, said the team discovered strong associations between specific SDSE strains and certain types of infections, something older testing methods did not reveal.

• The study was published in Microbiology Spectrum on March 31, 2026.

What’s next

The researchers say the new genetic data will help deliver insights that can improve diagnosis, infection control, and future vaccine planning for these dangerous streptococcal infections.