Bacteria are a type of microorganisms that are found in any type of matter, these present numerous forms and are the cause of some viral diseases which affect the majority of the world population, people can present from flu to more serious infections or Chronicles.
The antibiotics They have been one of the greatest advances for modern medicine. Hence, resistance to these drugs is currently one of the main threats to global health, according to the World Health Organization (WHO). This problem is a consequence of the adaptability and evolution of bacteria pathogens when faced with antibiotics.
A study by the Higher Council for Scientific Research (CSIC), based on the understanding of evolution as the basis for designing effective treatments against resistant bacteria, has shown that the alternation of the antibiotics ceftazidime and tobramycin or of ceftazidime and the combination tobramycin-fosfomycin is effective against infections by Pseudomonas aeruginosa, a bacterium that can cause lung, respiratory, urinary and other tissue infections as well as cause generalized infections in the body, especially in immunocompromised patients.
The combination of antibiotics proposed by the study, published in the journal Science Advances, is based on the phenomenon known as collateral sensitivity, an ‘evolutionary limitation’ of bacteria. “Since the 1950s we have known that bacteria, as a result of the acquisition of resistance to one drug, can become more sensitive to other drugs.
However, the possibility of exploiting this ‘evolutionary limitation’, which occurs as a consequence of the use of a first drug, is more difficult when infections occur by genetically different bacteria, such as those resistant to various antibiotics due to previous treatments.
When this happens, it is very difficult for the acquisition of resistance to occur following the same evolutionary pathways in all the bacteria that make up the infection, but if these conserved patterns of collateral sensitivity exist and we detect them, it is possible to start from this phenomenon to effectively treat infections of P. aeruginosa
”, Points Sara Hernando-Amado, researcher at the National Center for Biotechnology (CNB-CSIC) and co-author of the work.
Evolutionary path of resistance
“Our work demonstrates the robustness of the evolutionary pathway that allows the acquisition of resistance to the drug ceftazidime in different genetic contexts P. aeruginosa. Thus, it would be possible, at least in the case of different resistant bacteria that we have studied, homogenize heterogeneous populations using a first antibiotic, ceftazidime, and then use a second antibiotic, tobramycin or the combination of tobramycin-fosfomycin, to inhibit the growth of these bacteria, which would now be sensitive after the first drug, “says the scientist.
To reach these conclusions, the researchers have used the adaptive evolution laboratory (ALE) technique. “In recent years it has been shown that the misuse of antibiotics is one of the main causes of their loss of effectiveness. With this work we want to highlight the importance of studying the evolution of resistance to these drugs, since other possible evolutionary routes could be detected on the basis of which to design new strategies of treatment, making a more rational use of antibiotics ”, concludes the researcher.