Summary: Increased antibiotic residues found in wastewater and treatment plants increase antibiotic resistance, and antibiotic residues found in drinking water can pose a threat to public health.
Source: Karolinska Institute
Antibiotic residues in sewage and wastewater treatment plants in regions around China and India are likely to contribute to antibiotic resistance, and drinking water may pose a threat to human health, according to comprehensive analysis of the Karolinska Institutet published on The Lancet’s planetary health.
Researchers also determined the relative contributions of various sources of antibiotic contamination in waterways, such as hospitals, municipalities, livestock and pharmaceutical manufacturing.
“Our findings can help decision-makers target risk-reduction measures against environmental residues of priority antibiotics and at high-risk sites to protect human health and the environment,” says Nada Hanna, researcher at the Department of Global Public Health at Karolinska Institutet in Sweden, and the first author of the study.
“Efficient allocation of these resources is especially vital for resource-poor countries that produce large quantities of antibiotics.”
Bacteria that become resistant to antibiotics are a global threat that can lead to untreatable bacterial infections in animals and humans.
Antibiotics can enter the environment during their production, consumption and disposal. Antibiotic residues in the environment, such as in wastewater and drinking water, can contribute to the emergence and spread of resistance.
Among the major producers of antibiotics
Researchers examined levels of antibiotic residues that may contribute to antibiotic resistance from different aquatic sources in the Western Pacific Region (WPR) and Southeast Asia Region (SEAR), regions defined by the World Health Organization. These regions include China and India, which are among the world’s largest producers and consumers of antibiotics.
The researchers did this by performing a systematic review of the literature published between 2006 and 2019, including 218 relevant reports from WPR and 22 from SEAR. They also used a method called Probabilistic Environmental Hazard Assessment to determine where the concentration of antibiotics is high enough to likely contribute to antibiotic resistance.
Ninety-two antibiotics were detected in the WPR and forty-five in the SEAR. Concentrations of antibiotics above the level considered safe for the development of resistance (Predicted No Effect Concentrations, PNECs) have been observed in wastewater, effluents and effluents of wastewater treatment plants and receiving aquatic environments.
The highest risk was observed in wastewater and in the influent of wastewater treatment plants. The relative impact of various contributors, such as hospital, municipal, animal husbandry and pharmaceutical manufacturing was also determined.
Potential threat to human health
In receiving aquatic environments, the highest likelihood of levels above the threshold considered safe for the development of resistance was observed for the antibiotic ciprofloxacin in drinking water in China and in the WPR.
“Antibiotic residues in sewage and wastewater treatment plants can serve as hot spots for the development of antibiotic resistance in these regions and pose a potential threat to human health through exposure to different water sources, including drinking water,” says Nada Hanna.
Limitations to consider in interpreting the results are the lack of data on the environmental occurrence of antibiotics from many of the countries in the regions and the fact that only studies written in English were included.
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Source: Karolinska Institute
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Original research: Free access.
“Antibiotic concentrations and antibiotic resistance in aquatic environments of the western Pacific and Southeast Asian regions: A systematic review and probabilistic environmental risk assessment” by Nada Hanna et al. Planetary Health Lancet
Antibiotic concentrations and antibiotic resistance in aquatic environments of the Western Pacific and Southeast Asian regions: A systematic review and probabilistic environmental risk assessment
Antibiotic resistance poses risks to human health and there are concerns about the effect of environmental antibiotic residues in the selection and spread of antibiotic resistance. The aim of this study was to identify the levels of antibiotic residues that may select for resistance and their contributions from different aquatic sources, from various aquatic environmental compartments of the WHO Western Pacific Region (WPR) and Southeast Asia Region WHO (SEAR ), also in China and India.
A systematic review of empirical studies measuring antibiotic concentrations in aquatic environments, published between 2006 and 2019, and a probabilistic environmental hazard assessment approach were used to identify antibiotic concentrations that could select for resistance in aquatic environments. various aquatic environmental departments of WPR and SEAR, including in China and India. The assessment involved the use of measured ambient concentrations and predicted no-effect concentrations (PNECs).
The systematic review found 218 relevant studies out of 5230 selected by WPR and 22 relevant studies out of 2625 selected by SEAR; some of these relevant studies were largely from China (n=168) and India (n=15). 92 antibiotics in the WPR and 45 in the SEAR were detected in various aquatic compartments. Antibiotic concentrations that most likely exceeded the PNECs (0-100%) were observed in wastewater and wastewater treatment plant effluents and effluents. Antibiotic concentrations most likely exceeding the PNECs have also been observed in aquatic environmental compartments. The highest risk for developing resistance was in tap or drinking water from WPR and China for ciprofloxacin (62.5%). For each antibiotic, the relative contribution of potential sources of antibiotic contamination in waterways, such as hospitals, municipalities, livestock, and pharmaceutical manufacturing, was determined.
The concentrations of antibiotic residues found in the wastewater and wastewater treatment plants of WPR and SEAR make them potential hot spots for the development of antibiotic resistance, which creates human health risks from environmental exposure through the drinking water. These findings may help decision makers target risk reduction measures against environmental residues of priority antibiotics at high-risk sites and help focus research efforts in these regions of the world.
Swedish Research Council.