According to researchers from IB-Unicamp, microorganisms take advantage of the low resistance of the organism, caused by the use of antibiotics, to develop the disease
Researchers from the Biology Institute (IB) at Unicamp recently published in Cell reports, a high-impact scientific journal, an article that brings new contributions to the understanding of the protective mechanisms exerted by the intestinal microbiota in relation to bacteria Clostridium difficile, one of the main causes of intestinal infections in humans. According to the work, whose tests on animal models were carried out at the Immunoinflammation Laboratory of the Department of Genetics, Evolution, Microbiology and Immunology at IB, the microorganism takes advantage of a drop in the organism's resistance, caused by the use of antibiotics. , to attack the intestine, causing stomach pain, diarrhea and, in more serious cases, even the death of the patient.
Studies around the C. difficile They were coordinated by professor Marco Aurélio Vinolo and had the participation of five of his postgraduate students: José Luis Fachi, Jaqueline de Souza Felipe, Laís Passariello Pral, Bruna Karadi da Silva and Renan Oliveira Corrêia. The research also had the collaboration of other researchers from IB-Unicamp, FCA-Unicamp, University of São Paulo (USP) and University of Essex (United Kingdom). According to Vinolo, the bacteria C. difficile It is present in the environment and can survive for long periods of time. “This microorganism has a form of resistance called spores, which means it can survive for a long time, making it particularly problematic in the hospital environment,” he explains.
After coming into contact with the human being, the C. difficile it can lodge in the intestinal microbiota and produce toxins that attack the cells lining the intestine. Simply put, one of the main factors that lead bacteria to trigger the disease is the use of antibiotics. When an individual uses this type of medication, whether for dental treatment or as therapy after surgery, they become susceptible to infection by C. difficile. The antibiotic causes a reduction in the resistance exerted by the organism's intestinal microbiota, which opens the way for the microorganism to cause infection. “What we discovered is that, when affected, the intestinal microbiota stops producing short-chain fatty acids, which help protect the body from the action of this pathogen”, explains Professor Vinolo.
These acids, continues the professor, are produced by the intestinal microbiota from the dietary fibers we ingest. “We carried out tests on animal models that found that mice that were fed diets rich in fiber showed greater resistance to the action of the bacteria. The opposite occurred with animals that had a low-fiber diet,” he reports. The identification of this mechanism is important because it can favor the development of therapies to prevent or minimize the problems caused by C. difficile.
An approach that follows this idea and has shown good results, according to the researcher, is intestinal microbiota transplantation. In this case, bacteria present in the feces of a healthy individual are isolated and then administered to the person who has recurrent intestinal infections due to C. difficile. With this, the body's protection system is strengthened, preventing the development of disease by the bacteria. “This is an efficient therapeutic method, but it brings associated risks, as it is not possible to identify all the microorganisms present in the transplanted microbiota. There is the possibility that it also contains potentially pathogenic organisms associated, for example, with the development of diabetes, obesity and degenerative diseases”, warns Vinolo. In this sense, the fact that research has identified some microbiota products that can have a protective effect on infection can facilitate the development of prevention and treatment strategies for this pathology.
While science searches for more effective alternatives against the activity of C. difficile, people can help avoid intestinal infections by following some precautions that are, to a large extent, already known to everyone, notes the professor. “One of them, which is within everyone's reach, is to increase the consumption of dietary fiber, which contributes to the production of short-chain fatty acids, a natural 'enemy' of bacteria”, he recommends. Fiber can be found mainly in fruits, vegetables and whole grains.
Research line
The study involving the C. difficile It is part of a line of research coordinated by Professor Vinolo that investigates various aspects related to bacterial metabolism and its interaction with the body's cells. “The research that yielded the article published by Cell reports It took five years to complete and included the participation of master's and doctoral students, in addition to the collaboration of Professor Patrick Varga-Weisz's group. Currently, we have another work in the final stage of submission to a scientific journal that deals with another short-chain fatty acid. This also appears to have a protective effect on the body, but through a different mechanism. The idea is, in the future, to use the two compounds together to see if we can increase this protective effect”, he reveals.
The professor also highlights two aspects that he considers important in the context of the investigations carried out in his laboratory. The first of these is dialogue with national and international groups to exchange knowledge. “In our case, collaborations have worked very well because one side always learns from the other. Furthermore, we have promoted student exchanges, which also contributes to the advancement of research,” he notes.
The second point emphasized by Professor Vinolo refers to the interdisciplinary nature of the work. “Just one area cannot answer all the questions that arise during a study. In our case, we use knowledge offered by different areas such as immunology, nutrition and microbiology. Currently, it is not possible to do science without this type of interaction. What we try to do is explore the fact that knowledge and points of view are different, but complementary”, he points out. The research carried out at the Immunoinflammation Laboratory is financed by the São Paulo State Research Support Foundation (Fapesp) and Newton Fund, linked to the British government.
