Microbial communities in soil are complex and vast in numbers. There are, for instance, as many microorganisms in 1 gram of soil as there are humans on the entire planet.
The finding, which has yet to be published in a peer-reviewed journal, has been reported by the U.S. Department of Agriculture. With this, microbiologists discovered antibiotic-resistant bacteria in prairie soils. The researchers are of the view that the bacteria will have had little or no exposure to human or animal activity.
Antibiotics, and resistance genes, occur naturally in soil due to the interactions between microbial species competing for territory. For example, the bacterial genus Actinomycetes are capable of synthesizing antibiotics, which provide a natural antibiotic residue in soils (several species provided the basis of early antibiotics.) It still remains that around 80 percent of the antibiotics in clinical use originated from soil bacteria, either directly as natural products or as their semi-synthetic derivatives.
The reason for the examination is because Agricultural Research Service researchers are seeking to understand agriculture-related antibiotic resistance and links to animal production.
Dr. Lisa Durso, in a research note has indicated that ungrazed prairie soils close to Lincoln, Nebraska have various levels of bacteria with antibiotic resistance. The area selected was one that had little human impact and no animal grazing during the past 20 years.
The study showed all prairies contained bacteria that were resistant to tetracycline and cefotaxime. These are two commonly prescribed antibiotics that treat a wide variety of infections. Moreover, just under 50 percent of the samples contained bacteria resistant to two or more antibiotics. What is of arguably greater significance is that the broad activity of the resistance genes found in association with soil bacteria might afford protection against newly developed antibiotics.
It is hoped such examinations will allow microbiologists to differentiate antibiotic resistance caused by human antibiotic use from resistance that occurs naturally. This information could help to identify suitable areas for rearing animals.
