Summary: The increase in antibiotic residue found in wastewater and treatment plants increases antibiotic resistance and antibiotic residue found in drinking water may pose a threat to public health.
Source: Karolinska Institute
Antibiotic residues in wastewater and wastewater treatment plants in the regions around China and India risk contributing to antibiotic resistance, and the drinking water may pose a threat to human health, according to a comprehensive analysis from Karolinska Institutet published in The Lancet Planetary Health.
The researchers also determined the relative contribution of various sources of antibiotic contamination in waterways, such as hospitals, municipals, livestock, and pharmaceutical manufacturing.
“Our results can help decision-makers to target risk reduction measures against environmental residues of priority antibiotics and in 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 study’s first author.
“Allocating these resources efficiently is especially vital for resource-poor countries that produce large amounts 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 largest producers of antibiotics
The researchers have examined the levels of antibiotic residues that are likely to contribute to antibiotic resistance from different aquatic sources in the Western Pacific Region (WPR) and the South-East Asia Region (SEAR), regions as 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 the WPR and 22 from the 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. Antibiotic concentrations exceeding the level considered safe for resistance development (Predicted No Effect Concentrations, PNECs) were observed in wastewater, influents and effluents of wastewater treatment plants and in receiving aquatic environments.
The highest risk was observed in wastewater and influent of wastewater treatment plants. The relative impact of various contributors, such as hospital, municipal, livestock, and pharmaceutical manufacturing was also determined.
Potential threat to human health
In receiving aquatic environments, the highest likelihood of levels exceeding the threshold considered safe for resistance development was observed for the antibiotic ciprofloxacin in drinking water in China and the WPR.
“Antibiotic residues in wastewater and wastewater treatment plants may 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 sources of water, including drinking water,” says Nada Hanna.
Limitations to be considered when 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.
About this health and environmental neuroscience research news
Antibiotic concentrations and antibiotic resistance in aquatic environments of the Western Pacific and South-East Asia Regions: a systematic review and probabilistic environmental hazard assessment
Antibiotic resistance poses human health risks, 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 antibiotic residue levels that are likely to select for resistance and relative contributions from different aquatic sources, of various aquatic environmental compartments of the WHO Western Pacific region (WPR) and the WHO South-East Asia region (SEAR), including in China and India.
A systematic review of empirical studies that measured antibiotic concentrations in aquatic environments, published between 2006 and 2019, and a probabilistic environmental hazard assessments approach, were used to identify antibiotic concentrations that are likely to select for resistance in various aquatic environmental compartments of the WPR and SEAR, including in China and India. The assessment involved the use of measured environmental concentrations and predicted no-effect concentrations (PNECs).
The systematic review found 218 relevant studies of 5230 screened from the WPR and 22 relevant studies of 2625 screened from the 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 PNECs (0–100%) were observed in wastewater, and influents and effluents of wastewater treatment plants. Antibiotic concentrations that most likely exceeded PNECs were also observed in aquatic environmental compartments. The highest risk for the development of resistance was in tap or drinking water of the WPR and China for ciprofloxacin (62·5%). The relative contributions of potential sources of antibiotic contamination in waterways, such as hospitals, municipals, livestock, and pharmaceutical manufacturing, was determined for each antibiotic.
The concentrations of antibiotic residues found in wastewater and wastewater treatment plants of the WPR and SEAR make them potential hotspots for the development of antibiotic resistance, which creates human health risks from environmental exposure via drinking water. These findings can help decision makers to target risk reduction measures against environmental residues of priority antibiotics in high-risk sites, and help to focus research efforts in these world regions.