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USD Microbiologist Finds Possible Treatment for Bacterial Infections

VERMILLION, S.D. – A research team at the University of South Dakota led by microbiologist Michael Chaussee, Ph.D., is working on a possible therapeutic treatment for patients with Streptococcus pyogenes that does not utilize antibiotics. Human infection with Streptococcus pyogenes ranges in clinical severity from asymptomatic infection and uncomplicated “strep throat” to life-threatening diseases such as toxic shock syndrome.

Chaussee’s goal is to better understand why some people are asymptomatic whereas others will die, because the bacteria look almost identical in both situations.

When bacteria become invasive by entering the blood, lung or deep tissue, mortality rates can be up to 50 percent. The current treatment for these types of invasive diseases is to use a variety of antibiotics, but unfortunately, bacteria can become either resistant or tolerant to said antibiotics.

The USD research team has found a peptide that controls bacteria’s ability to produce toxins and it also interrupts the bacteria’s ability to communicate utilizing signaling pathways. The research team can disrupt bacteria’s ability to survive in blood by artificially adding this peptide.

“We envision the treatment would be IV administration for patients with life-threatening invasive Streptococcus pyogenes infections,” said Chaussee. “The therapeutic is a small molecule and specifically targets Streptococcus pyogenes, which means it would not disrupt the normal microbiome, which is beneficial.”

The next steps for this research project involve characterizing how the peptide affects toxin production and testing it in vivo. It is also possible that this therapeutic could target other bacterial species, such as Streptococcus pneumoniae, the most common bacterial cause of pneumonia. 


USD's Sanford School of Medicine is nationally known for excellence. With its award-winning curriculum, the school prepares medical students to practice in all fields of medicine and is particularly recognized and ranked for its reputation in family medicine and rural medicine. In addition to the M.D., it offers graduate degrees in basic biomedical science, sustains a vibrant and forward-looking research agenda, and is home to the interdisciplinary Center for Brain and Behavioral Research.


Founded in 1862 and the first university in the Dakotas, the University of South Dakota is the only public liberal arts university in the state, with 202 undergraduate and 84 graduate programs in the College of Arts & Sciences, School of Education, Knudson School of Law, Sanford School of Medicine, School of Health Sciences, Beacom School of Business and College of Fine Arts. With an enrollment of nearly 10,000 students and more than 400 faculty, USD has a 16:1 student/faculty ratio, and it ranks among the best in academics and affordability. USD’s 18 athletic programs compete at the NCAA Division I level.


Hanna DeLange
USD News