Many millions of people worldwide still die of infectious diseases every year, even though antibiotics have been thought to have defeated such diseases forever. A sometimes dramatic increase in antibiotic resistance is leading to science and medicine having to adapt to these highly-complex pathogens in a never-ending battle. In Germany, too, the overall situation has deteriorated significantly. While between 1975 and 1984 an almost unchanged level of resistance was observed in bacteria, in many bacteria thereafter the frequency of resistance increased enormously.

What are antibiotics and how do they work?

Antibiotics are substances that kill unicellular microorganisms (including the bacteria) (bactericidal effect) or impede their growth (bacteriostatic effect). Since the bacteria differ in essential points from the human body cells, for example cell wall, entirety of the heredity apparatus (genome), cell organelles for protein synthesis (ribosomes), the antibiotics can start at these sites in order to prevent their spread in humans.

Commonly spoken are broad-spectrum antibiotics that work against many different bacteria and narrow-spectrum antibiotics (specializing in certain pathogens). In addition to the usual antibiotics, the reserve antibiotics play an important role. They are used when antibiotic resistance occurs and / or very severe infections are present. However, they are often much more expensive, are often poorly tolerated, or / and they develop resistance very quickly.

Antibiotics in animal feed

Until 2006, the use of certain antibiotics was approved as so-called performance enhancers in animal feed. Especially fattening animals in large stables were continuously given a small dose of antibiotics in the form of a feed supplement. This served to promote the growth of animals and prevent disease.

This practice harbored a large reservoir of resistance genes because of the widespread use of antibiotics to systematically grow bacterial strains resistant to a particular antibiotic. The resistance of certain bacterial strains can spread to others and thus represents a high risk.

Therefore, the addition of antibiotics to feed in 2006 was banned throughout the EU.

Antibiotics in veterinary medicine

After the ban on antibiotics became effective in animal feed in 2006, the use of antibiotics for veterinary purposes increased. However, official figures are available only from the year 2011.

However, in recent years, the amount of antibiotics used in veterinary medicine in Germany has significantly reduced. While in 2011, 1, 706 tonnes of antibiotics were still sold by wholesalers to veterinarians, in 2015 they were only 805 tonnes. However, one should not disregard that there are still used antibiotics, which are actually intended as a reserve antibiotics for human medicine.

Antibiotics in gene technology

A little public field of antibiotic use is the use of antibiotic resistance as so-called marker genes in genetic engineering. They are called marker genes because they are supposed to mark genetically modified (transformed) cells. If these cells are placed on a medium soaked in the respective antibiotic, all cells die off, except for those who have taken up the marker gene and thus also the desired gene, which is to give the plant a new property. The antibiotic resistance gene thus plays only a purely technical role.

In the meantime, however, it is feared that "genetically modified plants and the bacteria can come to a horizontal gene transfer". This is theoretically possible everywhere where already decomposed plant material meets large amounts of bacteria, for example in compost, in the silage or in the gastrointestinal tract of humans and animals.

Although such a gene transfer is very unlikely, it can not be ruled out. For example, in the EU Deliberate Release Directive of autumn 2002, the use of antibiotic resistance markers has been significantly reduced but not generally banned.

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