Antibiotic resistance is a growing threat of present times. A recent study published in Nature Communications discussed the impact of sewage contamination in the development of antibiotic resistance.
Developments of resistant pathogens pose a great challenge in the field of medicine. Bacteria can evolve into resistant forms to overcome antibiotics and favour its survival. Sewage treatment plants are one of the most common sources of resistant pathogens. Daily, large volumes of sewage are treated in these plants and discharged into the environment. This treated waste has large amounts of gut bacteria and antibiotics consumed by humans and animals.
There is a huge amount of antibiotic-resistant bacteria and genes in sewage polluted environment. The question of whether these resistant genes are the cause of bacterial evolution or due to fecal contamination instigated the researchers, Antti Karkman and his team to conduct a study. This study was published in the open journal Nature Communications.
Antibiotic resistance impacted by fecal contamination
The researchers analyzed the contamination by antibiotic-resistant genes from nearly five hundred publicly available genetic data of sewage-polluted environmental samples. They studied fecal contamination by using crAssphage (a bacteria-eating virus found specifically in human feces). The ARG, CL1 and MG-RAST were the most commonly found antibiotic-resistant genes in these samples.
The presence of crAsspahge and antibiotic-resistant genes in the same sample established a definite relation between fecal contamination and antibiotic resistance. It clearly ruled out the evolution of resistant genes in fecal pollution, as a cause. However, they found high levels of antibiotic resistance genes in areas with high levels of antibiotic manufacturing.
Industrial areas of India and wastewater treatment plants of the United Kingdom and Singapore showed enormous amounts of antibiotic resistance genes. Treated sewage in Sweden and Wisconsin, USA demonstrated decreased load of these genes.
Study emphasizes considering fecal contamination in fight against antibiotic resistance
It emphasizes to consider fecal contamination in antibiotic resistance. The study also detects effluent from the drug manufacturing industries as an important source of antibiotic resistance genes.
It is important to note that there are limitations to this study. The levels of antibiotics were ignored, and the spread of antibiotic-resistant genes among the bacteria required exclusion by more accurate methods. Additional markers for contamination by animal excreta can also be used for further studies.
One of the authors of the study, D.G. Joakim Larsson at the University of Gothenburg in Sweden, stated in a press release, “The study indicates the importance of taking into account the level of fecal pollution when interpreting findings of antibiotic resistance in the environment. It implicates that one often does not need to explain such findings by on-site selection from residual antibiotics. But it does not exclude that there still is selection by low levels of antibiotics in the environment going in parallel. Other findings still suggest that low, environmental levels of certain antibiotics could select for resistance. This needs further research.”
Antibiotic resistance is a serious concern. It is very helpful to utilize this study principle to determine fecal contamination in antibiotic resistance. Proper sewage treatment and stringent laws in the disposal of wastes is highly essential to overcome the problem of antibiotic resistance.
Written by Dr. Radhika Baitari, M.S
- Karkman A, Pärnänen K, Larsson D. Fecal pollution can explain antibiotic resistance gene abundances in anthropogenically impacted environments [Internet]. www.nature.com/naturecommunications. 2019 [cited 24 January 2019]. Available from: https://www.nature.com/articles/s41467-018-07992-3
- Antibiotic resistance in the environment linked to fecal pollution [Internet]. EurekAlert!. 2019 [cited 24 January 2019]. Available from: https://www.eurekalert.org/pub_releases/2019-01/uog-ari010819.php