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By Lic. Silvana Buján
The overuse of antibiotics promotes the development of drug resistance for human pathogens. The second consequence is the generation of resistance of bacteria to these antimicrobials, which induces the use of higher concentrations of antibiotics for their treatment in living organisms, reaching limits dangerously close to intoxication.
Fleming spent much of his 73 years working as a medical microbiologist at St. Mary's Hospital in London. At the beginning of the First World War he held the position of military doctor on the French fronts. There he watched helplessly many people die from wound infections.
On the way back, he searched intensely for something to avoid this harsh agony. His discovery, penicillin, marked a change of course in modern medicine: a chemical molecule (penicillin) and a protein molecule (lysozyme) of antibiotic activity.
More than a century later, the overload, the irrational use and the discharge into the environment of antimicrobial agents put the human being before two unsuspected risks: resistance and the deterioration of the very base of biodiversity.
“The excessive use of antibiotics promotes the development of drug resistance for human pathogens. Antibiotics in the environment can also damage the natural processes necessary for the cycle of essential elements in the biosphere "says Professor, biologist and engineer Rolf Halden, from the Institute of Biodesign at Arizona State University, consulted for his research on the effects of antimicrobial dispersal in the environment. Halden's working group seeks to follow the path of active ingredients found in personal hygiene and cleaning products. The results are alarming: triclosan and triclocarban they settle in the sewage sludge, passing from there to soils and bodies of water, remaining there for several years. Halden points out that “Based on monitoring levels of antibiotics they can sometimes be detected in drinking water. Its effects at these levels we can presume to be insignificant, but its effect over time is not yet known, since m more research in this area ”.
Triclosan has been used since 1964 as an effective bactericide for the creation of sterile fields in health institutions. But these substances are not only applied intramurally: hand soaps, cleansing liquids, disinfectant gels are antimicrobial products that have been used massively since the eighties in industry, commerce and the home.
The chemical characteristics of these compounds make them very stable substances, difficult to degrade. To this is added that they are hydrophobic and that they tend to adhere to other particles, becoming more and more resistant and easy to be carried by the water or by the wind.
Dr. Halden determined in his studies that these compounds persist in sewage sludge from treated water, which ends up being disposed of as compost in farm fields. The alarm goes off because there are still no evaluations on the migration of these substances to food, and therefore, to man.
Damage to the environment from the use of antibiotics
When we take an antibiotic to clear an infection, its effective load is largely depleted inside the body. The same happens when we disinfect our home or wash our hands with antiseptic soaps, whose active ingredients run off through the pipes.
In the environments where they finally arrive, two things happen: the first is the death of numerous microorganisms, which in fact turn out to be the basis of the food chain of ecosystems. Many of the compounds can damage an important group of viruses and beneficial bacteria, which are responsible for carrying out biogeochemical processes essential for the recycling of nutrients. The second consequence is the generation of resistance of bacteria to these antimicrobials, which induces the use of higher concentrations of antibiotics for their treatment in living organisms, reaching limits dangerously close to intoxication.
The difficulty in treating infections caused by multi-resistant super microorganisms threatens human health and life itself.
The researcher Irma Rosas Pérez, from the Center for Atmospheric Sciences of the National Autonomous University of Mexico, responds about what type of antimicrobials are the most harmful to the environment: “Beta-lactams, sulfa drugs, fluroquinones, chloramphenicol. Most of the antimicrobials that persist in water or soil are broad-spectrum, thus damaging ecosystems as they can kill degrading microorganisms that are so important in mineralization of organic matter and nutrient production.
They are harmful to the primary producers necessary for energy to flow in ecosystems and to sustain diversity. In addition, those who do not die acquire genetic material to resist. And this material can be transmitted vertically or horizontally to other microorganisms, which can become pathogens for man ”.
But ... are so many used?
The figures in the United States only show a consumption of 25,000 tons per year, half as human medicines and half for veterinary and agricultural use, an aspect that we sometimes lose sight of.
In that country, medical prescription is compulsory, but in most of the American continent, antibiotics are bought without a prescription in pharmacies. And self-medication is commonplace in our Latino culture. Once we learned about a certain brand of antibiotic that a doctor prescribed us years ago, we continue to purchase the same product every time a similar symptom afflicts us.
In modern livestock, antibiotics are a basic piece because the use of low doses stimulates growth in confined animals. This causes them to be colonized by resistant bacteria. Their excreta contain those super microorganisms that return to the soil, the environment, magnified, cumulative and every year, more severe.
Resistant bacteria are also created in poultry and are often transferred to the employees of the pen. Irma Rosas Péres adds: “We found bacteria that have never had contact with man and that show resistance genes. The explanation is that the antibiotic is found in the environment that is contaminated with waste from humans or animals under treatment to control their infections. "
Antimicrobial packaging is used with increasing frequency in the food industry, which prevents the development of bacteria such as Listeria monocytogenes, contracted in the rural environment, fungi and other pathogens. But is it sure that they do not migrate to food?
Killing the bad guys, the good guys ... and the man?
The "miracle" of antibiotics capable of differentiating between a bacterium and a cell in the human body, has its problematic side as it also acts on all "good" bacteria that it contacts in the body. Patients who self-administer antibiotics frequently have increased numbers of resistant bacteria on their skin and in the gut, for example. But this kind of "post-therapeutic action" of the antibiotic is not the whole problem. Sales of bactericidal, fungicidal and disinfectant products in general for the home and personal hygiene have exploded. Triclosan and quaternary ammonium compounds reign there too, causing even more cross-resistance.
Máximo Sandín is a Doctor of Biology Sciences and professor of Human Evolution at the Autonomous University of Madrid. Consulted on the subject, he points out “Bacteria are fundamental components of life. They were responsible for oxygen on earth and for our very existence. Up to 40 million bacteria have been counted in one gram of soil. Both on land and in the sea they have strong actions in biogeochemical cycles. And in the human body it has been calculated that there are more than one hundred billion bacteria. They are essential for immunity, to keep us in balance with the outside. When a disease happens it is because some phenomenon destroys the balance and pathogenic bacteria are produced in response to that environmental aggression. "
For him, the incorporation of antimicrobials into the environment “through the excess consumption of antibiotics and the environmental impact of their use in livestock, in hygiene… is a consequence of this competitive conception that we have of nature. They have taught us that nature is a battlefield. And that antimicrobials are weapons. But we do not take into account that bacteria do not live alone, in Petri dishes. They live in colonies, in ecosystems, in networks of life. There is an emergence of neurological diseases, for example, whose origin can be associated with this indiscriminate killing of bacteria and viruses, such as multiple chemical syndrome, amyotrophic lateral sclerosis, and many others whose origin is in the enormous amount of chemical substances to which we are exposed, with weakened immune systems. The original peoples of America or Africa had a much more accurate conception of nature. Not as a battlefield, but as a concert in which all manifestations of life are essential.
This system of ours to destroy everything, is piercing the balance of life. The earth is a great ecosystem and this mass extinction has already begun, in fauna, flora, and also in bacteria. If this process is not stopped, the structure of life will inevitably collapse. "
Loose 1 - Effects of the two compounds studied by Halden
Both chemical compounds, triclosan and triclocarban, are listed as possible endocrine disruptors, in addition to affecting the nervous system and altering sexual development.
In the environment, being antimicrobial, it eliminates a considerable strip in the chain of life, making random cuts in the colonies of microorganisms, breaking basic environmental cycles in ecosystems, as well as affecting crustaceans and other aquatic organisms.
On the other hand, studies are making progress in determining whether among these microorganisms, “resistant super microbes” can also be generated, which would lead to a certain risk on people's health.
Loose 2 - What are they - How do they act
An antimicrobial is the substance that kills or inhibits the growth of microbes such as bacteria, viruses, fungi or parasites. In general, they are classified as:
- Antibiotics, Antifungals, Antiparasitics, among which are Anthelmintics and Antivirals.
- Disinfectants: they are applied to eliminate the possible microbial load.
- Sanitizers: They are applied to reduce the possible microbial load.
- Antiseptics: They control and reduce pathogenic microorganisms and are for external application in living beings, topically on the skin or mucous membranes.
- Antimicrobials for systemic use: they attack microorganisms that have colonized living tissues, being incorporated orally, absorbed through the skin or injected.
Silvana Buján is Argentina, graduated in Social Communication Sciences (Universidad Nacional de Quilmes) and a scientific and environmental journalist, practicing for more than two decades without interruption through radio and graphic media in the country and abroad. He is an environmental activist and participates, directs or coordinates non-governmental organizations and thematic networks. She is a lecturer and consultant on environment and development issues. He has obtained the 1st Prize for Scientific Dissemination of UBA (University of Buenos Aires) in 2009, the 1st Latin American and Caribbean Prize for Water CATHALAC-UNESCO in the same year, five Martin Fierro Prizes for his work on radio. He has been awarded the National Journalism Prize in 2007, the 1st Prize of the 2010 Tobacco or Health Congress, the 1st Prize for Health Journalism from the Argentine Medical Association 2010 and the 2nd Prize for Scientific Dissemination UBA 2010. He lives in Mar del Plata. Since 1998 ECOS (www.programa-ecos.com.ar) has been carrying out a cycle of scientific journalism focused on health, the environment and cultures. BIOS, NGO member of the National Network of Ecological Action and the Citizen's Anti-incineration Coalition is chaired. He is a member of the International GAIA Advisory Committee.