Photo credit: www.sciencedaily.com
In the ongoing battle against bacterial pathogens, innovative researchers are exploring a dual approach that merges vaccinations with the strategic use of benign microorganisms within the intestine. This method holds the potential to significantly alter the trajectory of the antibiotic resistance crisis.
The dynamics of intestinal bacteria present a paradox. While these microorganisms are essential for digesting food, the gut is also home to various harmful pathogens. Some of these can lead to conditions such as diarrhea, while others may remain dormant until circumstances arise—like a compromised immune system or intestinal wall damage—transforming them into threats that can result in severe infections or sepsis.
For years, scientists have been focused on developing vaccines against these intestinal pathogens, especially those bacteria that have developed resistance to conventional antibiotics. This endeavor is particularly challenging, as the immune response in the gut operates differently compared to the rest of the body, and the intricacies of the intestinal immune system remain partially understood.
Innovative Solutions
Leading a significant area of research in this field is Emma Slack, a professor at ETH Zurich and at the University of Oxford’s Sir William Dunn School of Pathology. Collaborating with Médéric Diard, a professor at the Biozentrum of the University of Basel, they have presented a promising method in a recent study published in the journal Science. Their research indicates that effectively formulated oral vaccinations against gut pathogens can be achieved not only by introducing the vaccine but also by combining it with harmless bacteria that outcompete the harmful ones for essential nutrients, thus starving them.
This strategy has shown to be effective in mouse models, successfully preventing salmonella colonization and effectively eliminating established E. coli bacteria. The results reveal that utilizing both the vaccine and helpful bacteria produced a significantly greater effect than using either method in isolation.
For the harmless microbial strains to effectively outcompete the pathogens, they must thrive under similar environmental conditions such as pH levels, oxygen availability, and nutrient sources. The research team meticulously selected or engineered appropriate competitor strains to ensure optimal conditions for success.
The study demonstrated that a highly effective salmonella competitor strain could be developed through genetic engineering, although it is also feasible to use naturally existing strains effectively combined without requiring genetic alterations, as evidenced by their trials using a mix of three native E. coli strains.
The Gardening Analogy
“We may be able to reduce harmful bacteria through vaccination, but we also need beneficial microorganisms to take over the ecological niche left behind,” Slack elaborates. “It’s akin to gardening; without planting alternative species after weeding, weeds will come back unabated.”
Prior research has suggested that some individuals possess intestinal flora that naturally keeps pathogenic strains in check, making vaccinations effective in these populations. By combining the competitor strains with vaccinations, it may broaden protection for those lacking such beneficial microbiota.
Reducing Reliance on Antibiotics
A key advantage of this innovative method is its capability to remove harmful bacteria without antibiotics. This approach is particularly significant given the rising prevalence of antibiotic-resistant infections, which pose serious public health concerns.
This method could enable the elimination of detrimental or antibiotic-resistant bacteria in patients prior to surgical procedures, a critical consideration for organ transplantation patients who require immunosuppressive therapy. The research team believes that this could lead to a notable decrease in antibiotic use in medical settings.
This strategy also holds promise for travelers venturing to regions where their immune systems might encounter unfamiliar bacterial strains. “The more efficient we are in reducing harmful and resistant bacteria within the populace, the better off everyone’s health will be,” asserts Slack.
Future developments might allow individuals to take a capsule containing both the vaccine and the beneficial bacteria. However, comprehensive research must first ensure the transition from model pathogens to clinically significant strains applicable to human populations.
This research was supported by the Basel Research Centre for Child Health, the National Centre of Competence in Research (NCCR) “Microbiomes” of the Swiss National Science Foundation, in addition to a Consolidator Grant from the European Research Council (ERC) awarded to Emma Slack.
Source
www.sciencedaily.com