2023 Author: Bryan Walter | [email protected]. Last modified: 2023-05-21 22:24
A group of American researchers have shown that two uropathogenic strains of Escherichia coli interact differently with the immune system of infected mice. One of the strains leads to chronic cystitis and can cause re-infection, while the other protects against recurrence. The article was published in PLoS Pathogens.
About half of women have a urinary tract infection once in their lives (men get sick about 30 times less often). Most often, the disease occurs due to uropathogenic strains of E. coli, and re-infection is often observed. This suggests that patients do not always develop adaptive immunity against some strains - the body "does not remember" enemies.
To effectively combat foreign bacteria, the mammalian immune system recognizes the proteins that pathogens carry on their surface. Even in related strains, these proteins are different, which is why immune cells do not recognize them in the same way. Several years ago, the features of the disease were described when mice were infected with the E. coli UN189 strain. Researchers from the University of Washington School of Medicine led by Thomas Hannan and Scott Hultgren decided to compare the course of diseases caused by two strains of E. coli that infect humans: CFT073 and UN189. They injected bacteria into mice, causing them to develop cystitis, an inflammation of the bladder. The authors of the article studied the nature of the course of the disease and assessed the likelihood of developing a chronic infection or its recurrence.
Both strains resulted in a chronic course of cystitis (four weeks) in mice. When the animals with CFT073 were not treated with antibiotics, they themselves got rid of the bacteria after eight weeks. However, after a course of antibiotics, the mice were resistant to reinfection: antibodies were efficiently synthesized against CFT073. UN189 did not leave the bladder of the animals at all; secondary infection after the use of antibiotics again caused inflammation. When the T cells responsible for the adaptive immune response were removed from mice, CFT073 was more likely to result in long-term chronic cystitis and the likelihood of recurrence increased.
Percentage of mice infected with strain CFT073: which developed cystitis and were cured 1-7 or 8-28 days after infection. With the removal of T lymphocytes (CD4 / 8), the percentage of mice with chronic cystitis is higher (60 percent) compared to the control (isotype, 40 percent).
Thus, when infected with CFT073, the body produces an adaptive immune response, which prevents the infection from re-developing. Several components of the envelope of the UN189 strain are likely to help it sabotage the immune system. As a result, it lives longer in the body and can cause relapses, since the host's immune cells do not remember it.
The data obtained on the influence of the genetic diversity of uropathogenic strains on the course of the disease will help the development of drugs and vaccines in the era of the war with antibiotic-resistant bacteria. In our materials you can read about antibiotics against the causative agents of tuberculosis and gonorrhea.