Probiotics are sold as "good" bacteria that help screen out "bad" types of microbes that camp in our intestines. However, a new experiment on mice has shown how our microbial allies can become treacherous madmen who could damage the gut.
The news is not all bad – we can use their propensity to turn these intestinal bugs into better bacteria.
"When we use living things as medicines, we have to realize that they are & # 39; they will adapt, and that means that what you put into your body is not necessarily what, even a few hours will be there later, "says pathologist and biomedical engineer Gautam Dantas.
Unlike other forms of medication, living organisms literally have their own life. What you swallow can reproduce itself. And what can reproduce can change.
"There is no microbe immune to evolution," says Dantas.
Dantas led a research team at the University of Washington to study a bacterium used to fight diarrhea
Just over 1
In particular, a variety is still characterized by its talent in the fight against acute diarrhea, especially in young children. E. coli Nissle 1917 (EcN) has proven to be a safe and effective treatment for a deadly condition.
To evaluate the potential of developing EcN after ingestion, the research team used specially bred mice that were completely germ-free.
The subjects were divided into four groups, each with different gut microbiotics. One was left completely sterile; the other three received microbiomas that reflected various healthy and unhealthy conditions.
Each group received EcN and was then fed one of the following options – boring old Labmaus chow, a more natural mouse-friendly diet, a westernized diet of fats and sugar and a westernized diet with some fiber.
Five weeks later, the mice were examined for the intestine. The lucky little E. Coli ? It turned out that not all of them were as friendly as they were on the road, especially on entrails that were less than healthy.
Inside mice that were filled with Westernized food, EcN had collected mutations that helped them cope with stress and use all those carbohydrates to stay longer than intended.
These bacteria also became slightly stickier, giving them a competitive edge over the other residents.
More worrying was the fact that EcN had developed a low level of resistance to the antibiotic in a group of mice treated with streptomycin.
"In a healthy, diverse environment, we may not have had much adaptation because this is the background Nissle is used to," says Aura Ferreiro, a graduate student in Biomedical Engineering.
"But you have to remember that we often do not use probiotics in people with a healthy microbiome."
These tricks could have been good news for the probiotic E. coli tries to make a home in their new environment, but there is considerable concern for their host.
Sticky bacterial cells that manage stress by developing easily to break down carbohydrates are not what we sign for probiotics
The results show that popular probiotics like EcN are not the kind of friendly guests who We want to be in our homes, but are opportunistic scavengers who turn against us if we do not treat them with the right affection
Before we rage our germs, you should consider a few things.
This is a study on mice. As we all know, there is a leap in anatomy between these tiny mammals and humans. This is a good first step in the research that justifies an investigation but does not give immediate cause for concern.
The study also contains an interesting epilogue. The research team introduced a gene for the degradation of the amino acid phenylalanine in their strain of E. coli and developed it into a probiotic.
Some people call themselves phenylketonuria, which prevents them from breaking down this protein building block on their own, leading to an accumulation that can damage the brain. 19659003] The administration of this probiotic agent to mice developed under similar conditions temporarily helped them to metabolize phenylalanine and lowered their levels by half. Similar studies by other researchers suggest that genetically engineered probiotics are the future of medical treatments for a range of diseases.
The DNA of the engineered EcN remained relatively stable during the week of treatment, suggesting that ordinary probiotics could benefit from a helping hand to become tiny masters of gut health while maintaining loyalty.
"We can use the principles of evolution to develop a better therapeutic that is carefully tailored to the people who need it, this is a chance, not a problem," says Dantas.
Probiotics have great potential for our health. We just have to learn how to keep them on our side.
This research was published in Cell Host & Microbe .