Women's Health

February 28, 2022

Invasive strep can defy zinc toxicity

Vanderbilt researchers find that invasive Group B Streptococcus strains, a significant risk to pregnant patients and infants, can grow in presence of toxic zinc levels.

Group B Streptococcus (GBS) is a commensal bacterium in the human gut and reproductive system, but it can sometimes cause severe disease in pregnant patients and lead to infant death. 

To understand the critical factors that differentiate GBS from a friendly gut bacterium to an invasive pathogen, Jennifer Gaddy, PhD, and colleagues grew thirty clinical GBS isolates under toxic zinc conditions and tested the impacts on bacterial growth. Zinc plays a vital role in both the host and pathogen survival, but too much zinc can be toxic to bacteria — a defense strategy exploited by the host’s immune cells. 

The scientists, led by graduate student Jamisha Francis, showed that high zinc levels did not impact the growth of invasive strains of GBS, indicating that disease-causing GBS may have evolved to resist zinc toxicity.   

The study, published in BMC Microbiology, provides a better understanding of how certain strains of GBS cause invasive disease during pregnancy and further advocates for innovative ways to treat GBS disease.

This research was funded by the National Institutes of Health (grants HD090061, GM133602, HL007411, and AI112541) and the Department of Veterans Affairs.