Researchers solve the cell structure responsible for traveler’s diarrhea

According to the World Health Organization, the enterobacterial bacterium Escherichia coli (ETEC) causes the largest number of cases of community-acquired diarrhea on record in the developing world and is the most common cause of traveler’s diarrhea. While this is only an annoying nuisance in healthy adults, in infants and young children it can lead to chronic malnutrition, stunted growth, and impaired cognitive function.

ETEC uses long, thin filaments called ‘pili’ to attach to the host intestinal epithelium, a vital early step in the pathogenesis of diarrhoea. These fibers are essential for the initiation of infection in the intestine by ETEC. Now, researchers from Boston Tchobanian University and Avedissian College of Medicine have found that barley is fine-tuned for their preferred microenvironment, such as the gut or urinary tract. They also find that some use short loops to tie themselves together. Others use long stretches to stretch a long distance. This discovery has important implications for creating better treatments against diarrheal diseases.

“Unwinding (and wrapping) the barley reduces the force at the site of adhesion, and allows the bacteria to remain attached. Because the filament is necessary for bacteria to cause disease, finding a way to prevent jaws from unwinding and wrapping in the future could be used to prevent diarrheal disease,” explained corresponding author Esther Pollitt. , PhD, assistant professor of physiology and biophysics.

The researchers used a combination of methods that included imaging the hair in a near-native state using a cryogenic electron microscope, using a laser to pull the hair out and measuring the force needed to untie it, and computer simulations to watch the atom unravel. level.

Because pili contains different strains of bacteria that adjust according to their environment, researchers are looking for ways to specifically target disease-causing bacteria. “Therapies that inactivate barley and allow bacteria to be washed away have advantages over current antibiotics, because physical removal will not lead to the development of resistant strains and only pathogens will be targeted, leaving the ‘good’ bacteria of the microbiome intact,” Pollitt said.

These discoveries appear online in the journal building.