Queensland researchers have uncovered that a genetic mutation enables certain E. coli bacteria to induce severe illness in individuals, while others remain benign, a discovery that could aid in the battle against antibiotic resistance. The findings were published in Nature Communications by Professor Mark Schembri and Dr. Nhu Nguyen from The University of Queensland’s Institute for Molecular Bioscience, along with Associate Professor Sumaira Hasnain from Mater Research, who identified the mutation in the cellulose production mechanism of E. coli bacteria.
Professor Schembri explained that this mutation grants the affected E. coli bacteria the ability to spread more extensively throughout the body, infecting organs such as the liver, spleen, and brain.
“Our research clarifies why certain E. coli strains can lead to life-threatening conditions like sepsis, neonatal meningitis, and urinary tract infections (UTIs), whereas others coexist harmlessly in our bodies,” Professor Schembri stated. “The ‘beneficial’ bacteria synthesize cellulose, whereas the ‘harmful’ bacteria are unable to do so.”
Bacteria generate various substances on their cell surfaces that can either activate or suppress the host’s immune system.
“The mutation we identified disrupts the production of the cell-surface carbohydrate cellulose in E. coli, resulting in heightened inflammation in the host’s intestinal tract,” Professor Schembri elaborated. “Consequently, the intestinal barrier breaks down, facilitating the spread of the bacteria throughout the body.”
Through models simulating human diseases, the team demonstrated that the inability to produce cellulose increased the virulence of the bacteria, leading to more severe illnesses, including meningitis affecting the brain and UTIs impacting the bladder.
Associate Professor Hasnain emphasized the significance of comprehending how bacteria move from intestinal reservoirs to other parts of the body in infection prevention.
“Our discovery sheds light on why certain E. coli strains become more perilous and offers insight into the development of highly virulent and invasive bacterial variants,” she added.
Professor Schembri highlighted that E. coli remains the predominant pathogen linked to bacterial antibiotic resistance.
“In 2019 alone, nearly 5 million global fatalities were attributed to bacterial infections, with E. coli accounting for over 800,000 of these deaths,” he noted. “Given the escalating threat of superbugs resistant to all existing antibiotics worldwide, discovering new approaches to impede this infection pathway is crucial to curbing the incidence of human infections.”
The collaborative effort involved teams from UQ’s School of Biomedical Sciences under the leadership of Associate Professor Jana Vukovic and from Griffith University’s School of Pharmacy and Medical Sciences led by Professor Glen Ulett.