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A new avenue for fighting drug-resistant bacteria

July 15, 2021 | Audrey-Maude Vézina

Update : July 14, 2021

Targeting an RNA sequence in pathogenic bacteria could make them more sensitive to antibiotics.

3D representation of Escherichia coli (E. coli) bacteria.
E. coli bacteria can cause urinary tract infections that are difficult to treat because of its resistance to antibiotics.

A small regulatory RNA found in many problematic bacteria, including Escherichia coli, appears to be responsible for managing the response of these bacteria to environmental stresses.  Professor Charles Dozois from Institut national de la recherche scientifique (INRS) and doctoral student Hicham Bessaiah see a promising avenue for more effective treatment of antibiotic-resistant bacteria. Their results have been published in the journal PLOS Pathogens.

In conducting their work, the researchers and their team observed that the elimination of this regulatory RNA sequence had an effect on urinary tract infections related to E. coli. These infections are among the world’s most common, especially in women, but they are sometimes hard to treat due to antibiotic resistance.

E. coli is normally found in the intestinal flora, but when it migrates to the bladder, the conditions there are completely different. The bacteria have to withstand the environmental stressors in order to cause a bladder infection. “Without the regulatory RNA, the bacteria is more sensitive to changes in the environment and loses its infectious capacity,” explained the doctoral student.

Inhibiting the RNA sequence

The idea is to block the RNA and make the bacteria less infectious, especially in the case of chronic infection, which can lead to increased resistance to treatment. If the bacteria are less resistant to stress, it will be more vulnerable to the host’s immune response. Regulation of the systems that make it virulent will also be disrupted.

“People with recurrent urinary tract infections take antibiotics regularly. This leads to resistance and limits treatment options, which is why it’s important to find alternatives.”

Charles Dozois, specialist in microbiology and immunology

The relationship between virulence and stress isn’t unique to urinary tract infections. The regulatory RNA sequence studied by the researchers is also found in a number of other major pathogenic bacteria. Given that the RNA seems to impact multiple functions, the research group is working to better understand the mechanisms of regulation before pursuing additional research on antibiotic-resistant strains of bacteria. 

About the study

The article “The RyfA small RNA regulates oxidative and osmotic stress responses and virulence in uropathogenic Escherichia coli” by Hicham Bessaiah, Pravil Pokharel, Hamza Loucif, Merve Kulbay, Charles Sasseville, Hajer Habouria, Sébastien Houle, Jacques Bernier, Éric Massé, Julien Van Grevenynghe, and Charles M. Dozois was published in PLOS Pathogens. The research group received financial support from the Natural Sciences and Engineering Research Council of Canada (NSERC), the  Canadian Institutes of Health Research (CIHR), and the Swine and Poultry  Infectious Diseases Research Centre (CRIPA) funded by Fonds de recherche du Québec – Nature et technologies (FRQNT)