Drug resistance is a common problem due to the human activities. Indiscriminate use of antibiotics has resulted in the development of resistance in disease-causing bacteria (microorganisms) found in soil. But, scientists have also found this resistance even in the soil from remote regions far away from human influence.
Source: Van Goethem, MW, Pierneef, R., South, OK, Van De Peer, Y., Cowan, DA, & Makhalanyane, TP (2018). A reservoir or ‘historical’antibiotic resistance genes in remote pristine Antarctic soils. Microbiome, 6 (1), 40. doi: 10.1186/s40168-018-0424-5.
Figure 1. Glacier in Antarctica (Source: Fred Walton, NOAA. Wikimedia Commons)
Antibiotic resistance is an emerging problem worldwide where the harmful microorganisms become resistant to the antibiotics and reduces the efficacy of these drugs. Antibiotics are the medicines prescribed to us when we get sick due to small, harmful organisms (known as microorganisms). These antibiotics then kill the harmful microorganisms and we recover! But, when antibiotics are used too much or not as prescribed, the harmful microorganisms can develop protection against the antibiotics. As a result, these antibiotics are unable to kill the microorganisms and are no longer effective. Antibiotic resistance has been on rise for a while and is becoming more common with each passing day.
Antibiotic resistance can also rapidly spread in nature in both humans, as well as in animals. One way this can occur is when antibiotics end up in the soil, which is home to many other microorganisms. Human activities, particularly the misuse of antibiotics, is often blamed for this. However, there is currently not much evidence to support this.
Figure 2. Antibiotics are prescribed as medicines to treat any microbial infection (Source: Naille Tairov. Wikimedia Commons)
Antibiotic resistance in isolated regions
In order to investigate the occurrence of antibiotic resistance, researchers have looked into the remote regions including caves in Alaska, and, in a recent study, soils around Antarctic glaciers. Their work focused around answering the question of whether or not antibiotic resistance occurred before the invention of modern antibiotics. They hypothesized that these remote regions have experienced minimal human impact and the presence of antibiotic resistance in these environments would suggest it is a natural process and not just a result of human influence. Microorganisms in soil can produce their own antibiotics as a defense strategy against other types of microorganisms competing for the same resources. The scientists thought it could be possible that the competing bacteria could develop resistance to these, leading to antibiotic resistance as a result of purely natural processes without human influence. When they investigated these remote soils in Antarctica, this is what they found.
Resistance in the glacial environments
In this study, researchers sampled surface soil from various ice-free sites in Antarctica and analyzed the DNA of the microorganisms that were in the soil. They looked for the presence of antibiotic resistance genes, which are specific segments of DNA that give the microorganism the ability to survive exposure to antibiotics. They found antibiotic resistant genes for the natural antibiotics produced by competing microorganisms, but did not find the resistant genes for the man-made antibiotics. With these findings, the researchers finally concluded that the antibiotic resistant genes in the glacial soils could be the “legacy” genes acquired over time across various related bacteria living in that environment. And this means that the resistance conferring genes have been passed through generations of microbes ages ago in these geographical regions.
According to these researchers, the future studies could deal with understanding the relationship of human activities and these resistant genes of the pristine environment. Further, this study also provides the information on how antibiotic resistance impacts the diversity of soil microbes.