A new study performed by Newcastle University and the Indian Institute of Technology, Delhi, measured metal and antibiotic resistance in sediments from the Ganges and Yamuna Rivers in India and streams in the River Tyne catchment.
The outcomes display that heavy metals, which are high in the River Tyne catchment as a result of the historic mining and industrial activity, connect to antibiotic resistance levels in the river. The same was observed in the Indian rivers, particularly in regions of industrial activity.
The team analyzed the relationships between heavy metals concentrations, metal resistance gene (MRG) and antibiotic resistance gene (ARG) abundance. The study has been published in the Environmental Pollution journal.
The study displays that MRG and ARG abundances increase where metal levels are greater, implying that reaches with metal pollution have increased antibiotic resistance, even when increased antibiotics are not clear.
The outcomes suggest that metal pollution also impacts resident bacteria, with Firmicutes and Bacteroidota being the amplest phyla at sites with high metal pollution. Such bacteria are generally seen in metal-contaminated surroundings and are known to take MRGs and ARGs in groups in so-called “gene cassettes”. This describes why metal exposures can result in antibiotic resistance.
The study reveals that particular metal combinations that encourage the powerful bacterial responses are Cobalt plus Nickel, and the combination of Zinc, Cadmium, and Cobalt.
The work does not necessarily imply a health risk, but it shows that a river or stream without antibiotics pollution can still have elevated antibiotic resistance due to other pollutants, such as metals.
David Graham, Study Co-Author and Professor, School of Engineering, Newcastle University
Graham added, “However, in a river like the Yamuna, which has high metals in combination with many other pollutants, greater concerns about the spread of antibiotic resistance exist.”
High metal exposure has the potential to co-select for antibiotic resistance in bacteria, making them potentially resistant to multiple antibiotics.
Dr. Sonia Gupta, Study Lead Author, Indian Institute of Technology
Dr. Gupta also noted, “The impacts of heavy metals-induced antibiotic resistance get exacerbated when high metal levels are combined with other pollutants such as antibiotics, detergents, and other chemicals, highlighting the importance of reducing heavy metal pollution as part of One Health solutions for reducing ARG transmission and spread.”
Antibiotic resistance, also known as AMR, is a significant global public health problem that impacts the effective treatment of an increasing number of infections caused by fungi, viruses, bacteria, and parasites.
Antibiotic use selects for resistance strains in human and animal wastes, which could be liberated to the surrounding through wastewater, thereby spreading ARGs and AMR bacteria throughout nature.
Gupta, S., et al. (2022) Effects of heavy metals pollution on the co-selection of metal and antibiotic resistance in urban rivers in UK and India. Environmental Pollution. doi.org/10.1016/j.envpol.2022.119326.