A new study in Environmental Science and Technology reports that soil microbes have become progressively more resistant to antibiotics over the last 60 years, despite more stringent rules on the use of antibiotics in medicine and agriculture.

The study involved an analysis of 18 different antibiotic resistance genes (ARGs) to four different classes of antibiotics in soil samples collected in the Netherlands from 1940 to 2008.

 Using data from sites around the Netherlands, the scientists found increasing levels in 78 percent of the ARG tested, clearly indicating increased potential for resistance over time. Because soil samples were only collected from the Netherlands, the scientists conclude their report by suggesting that further studies need be performed around the world so that the scope and possible ramifications of their results can be better understood.

Researchers note that, although scientists have known for years that resistance was increasing in clinical situations, this is the first study to quantify the same problem in the natural environment over long time-scales. They express concern that increased antibiotic resistance in soils could have broad consequences to public health through potential exposure through water and food supplies. Their results "imply there may be a progressively increasing chance of encountering organisms in nature that are resistant to antimicrobial therapy."



Citation: Knapp et al., 'Evidence of Increasing Antibiotic Resistance Gene Abundances in Archived Soils since 1940', Environ. Sci. Technol., 2010, 44 (2), pp 580–587; doi: 10.1021/es901221x