The consequences of antibiotics in animal fattening
Research at the Robert Koch Institute in Wernigerode has shown that the use of antibiotics in animal fattening contributes significantly to the spread of certain resistant bacteria and their resistance genes to humans. The Federal Ministry of He alth then worked towards a ban on the use of the glycopeptide antibiotic avoparcin as a feed additive to accelerate weight gain in animals, which was issued for Germany by the Federal Ministry of Food, Agriculture and Forestry in January 1996. A review article by Wolfgang Witte from the Robert Koch Institute on the subject has now been published in the leading American scientific journal Science (Science 279).
Further investigations by the working group headed by Prof. Witte have now shown a clear reduction in the frequency of the occurrence of glycopeptide-resistant enterococci in meat products. In 1994, all samples of commercially available poultry were massively colonized by glycopeptide-resistant enterococci, while in 1997 this was only the case in 25 percent of the samples examined. In the same period, there has also been a decrease in the infestation with the resistant bacteria in humans. While in 1994 they were still found in 12 percent of he althy, non-hospitalized people, in 1997 the pathogen only appeared in 3.3 percent of test subjects. As a result of this decline, it can also be expected that glycopeptide-resistant enterococci will be introduced into hospitals much less frequently, where they have repeatedly led to severe infections in previously injured patients.
A situation comparable to that before the ban on avoparcin for animal fattening can also be found with other antibiotics. Resistance to the antibiotic virginiamycin, for example, was found in pathogens that had caused infections in humans before it was even used to treat patients. However, virginiamycin has long been used as a growth promoter in animal fattening. The RKI scientists were able to detect the corresponding resistance gene in enterococci from fattening animals and meat products.
"The research results obtained at the RKI in Wernigerode suggest that antibiotic fattening accelerators in animal fattening should be completely avoided in the future in order to avoid risks to human he alth that can no longer be calculated," says Prof. Reinhard Kurth, head of the Robert Koch Institute. In Sweden, for example, the use of antibiotics in animal fattening has been banned since 1986.
The development of resistance of bacterial pathogens to antibiotics is determined by two main components: the presence of transmissible resistance genes on the one hand and the selection pressure to which the pathogens are exposed through the use of antibiotics on the other. Hospital patients, who are naturally particularly susceptible to infections and therefore need to be treated with antibiotics, and industrially reared fattening animals are currently the two main reservoirs of antibiotic resistance. In addition to being used for therapy and prophylaxis as a result of chains of infections, which can spread very quickly in large fattening herds, significant amounts of antibacterial agents are also used in animal fattening as growth promoters.
