New antibiotics are said to reduce environmental pollution
The accumulation of antibiotics in the environment is a massive problem, mainly because it leads to the increased development of resistant pathogens. Scientists at the Leuphana University of Lüneburg have now developed an antibiotic that does not accumulate in the environment and can therefore prevent the development of resistance.
In their research, the scientists concentrated on the broad-spectrum antibiotic ciprofloxacin, which is used frequently and, like other antibiotics, is released into the environment largely unchanged after medical use. The drugs remain active there and even small concentrations of the active ingredient promote the development of resistant pathogens, reports the team led by Professor Dr. Klaus Kümmerer from Leuphana University. The scientists have therefore developed an antibiotic in this class of substances which is rendered ineffective in the environment by natural decomposition processes.
Enrichment of antibiotics in the environment
According to the experts, around 33 tons of the active ingredient ciprofloxacin are used in Germany in human and veterinary medicine - and the trend is rising. However, ciprofloxacin does not break down into the environment after exiting the body and is also not biodegradable. Instead, the active ingredient accumulates in water, its sediments or in sewage sludge. With the use of sewage sludge as fertilizer, ciprofloxacin can also be obtained in soils. In addition, the active ingredient is introduced directly into the soil with the manure through use in animal husbandry.
Degradable active ingredients in demand
Even low ciprofloxacin concentrations in soils or sediments and bodies of water can contribute to the spread of resistance, according to the researchers. In addition, ciprofloxacin - similar to other active pharmaceutical ingredients - is taken up by food plants. In order to reduce the pollution and danger from antibiotics, active ingredients that are biodegradable and break down must be used. The answer of the Lüneburg scientists is "Benign by Design". An approach in which new molecules are designed so that they are ultimately more environmentally friendly.
Five years of research
The scientists concentrated their work on the active ingredient ciprofloxacin, as it is used frequently and remains in the environment for a particularly long time. Based on ciprofloxacin, they spent five years researching the development of an antibiotic "which disintegrates after its medical use and is no longer active," the university said. To do this, we first had to “get to know the molecule very well,” emphasizes Dr. Christoph Leder from Leuphana University.
Working ingredients now available
The challenge was to destabilize the chemical bonds of the active ingredient so cleverly that they remain sufficiently stable in the blood, for example, but disintegrate after they have passed through the body. The scientists succeeded and the newly developed active ingredients have already been registered for a patent by the Leuphana University. Professor Kümmerer emphasizes that active substances are now available that work in the test tube. However, there is still no finished drug. This is now the task of potential partners in the pharmaceutical industry.
Clarification process an incubator for resistant bacteria
The need for biodegradable antibiotics is great. For clarification, Dr. Leather, that with ciprofloxacin alone seven times the water volume of Lake Constance would be required "in order to dilute the amount used in Germany every year to a safe concentration." Because the wild-type bacteria are attacked by the medication, but the resistant mutants do not react and can continue to divide. In this way, the entire clarification process becomes an "incubator for resistant bacteria", emphasizes Dr. Leather. According to the latest findings, significantly lower concentrations than previously assumed are an advantage for the mutant bacteria.
Degradability in the environment as an approval criterion
Given their current study results, Professor Kümmerer and colleagues hope that the degradability of antibiotics and other active pharmaceutical ingredients in the environment will become an approval criterion in the future, as the feasibility has now been demonstrated. Overall, success could become a "game changer" because "new molecules also open up new market opportunities, especially if, like in this case, they have had their environmental compatibility built in from the start," emphasizes Professor Kümmerer. (fp)