In a recent study published in lancet planet healthresearchers investigated antibiotic levels and antibiotic resistance in aquatic environments.

Antibiotics are regarded as developing contaminants of the aquatic environment that can facilitate the establishment and selection of antibiotic resistance in the environment. However, wastewater treatment plants and other waste management systems can partially remove antibiotic residues. Studies indicate that antibiotics are prevalent in the aquatic ecosystems of the World Health Organization (WHO) Western Pacific Region (WPR) and WHO Southeast Asian Region (SEAR). Assessing antibiotic levels in aquatic habitats where resistance may emerge is essential to characterize public and environmental health hazards and inform appropriate corrective actions.

Study: WHO Antibiotic Concentrations and Antibiotic Resistance in the Aquatic Environment of the Western Pacific and Southeast Asia Region: A Systematic Review and Probabilistic Environmental Hazard Assessment. Image Credit: LI SEN / Shutterstock

About research

In this study, researchers at the Karolinska Institutet (Stockholm, Sweden) found antibiotic residue concentrations likely to be selected for resistance, along with relative contributions from different aquatic sources. .

In this systematic study, a literature search was conducted to determine antibiotic residue concentrations in WPR and SEAR aquatic habitats and to conduct probabilistic environmental hazard assessments. Studies were eligible if they were original. A documented antimicrobial or antibiotic administered for systemic use in animals or humans. Reported antibiotic group, type, or class. All water samples from the environment were recorded, including river water, drinking water, lake water, groundwater, wastewater, seawater, and effluents and influents from wastewater treatment plants. Eligible studies also estimated antibiotic residue levels in one or more water compartments. The included research must have been conducted under WPR or SEAR and published between 2006 and 2019.

After data were acquired and collected from primary sources, they were used for probabilistic environmental risk assessment. The likelihood of each antibiotic-associated environmental outbreak crossing the threshold for antibiotic resistance development was calculated at varying proportions of exposure within the aquatic environmental compartments of SEAR, WPR, India, and China. The team developed a probabilistic environmental hazard assessment model using the environmental exposure distributions of the highest observed environmental levels of antibiotics corresponding to each water compartment.

Predicted threshold levels were derived from the associated centiles of the measured environmental concentration distributions associated with the highest antibiotics reported in various aquatic environments, and the rates of exceedance associated with antibiotic thresholds in the development of antibiotic resistance. was calculated. These calculations used the predicted no-observed-effect concentration (PNEC) threshold for the development of antibiotic resistance.

result

This systematic review of antibiotic residue levels in the aquatic environment consisted of 218 of 5230 relevant studies assessed from WPR and 22 of 2625 screened studies from SEAR. Most of the relevant studies were from India and China. WPR identified nearly 92 antibiotics, while SEAR identified 45.

Residues of veterinary and human antibiotics have been found in numerous aquatic environmental compartments associated with SEAR and WPR. Various classes of antibiotics, including fluoroquinolones, β-lactams, macrolides, lincosamides, tetracyclines, sulfonamides, glycopeptides, amphenicol, and aminoglycosides, are not only subject to WPR’s aquatic environment, but also wastewater, wastewater, and in influents of wastewater treatment plants. and SEAR.

A probabilistic environmental risk assessment yielded predicted threshold concentration values ​​associated with different percentiles associated with the distribution of environmental exposures for the highest detected environmental levels of antibiotics. Antibiotic levels related to fluoroquinolones, tetracyclines, macrolides, β-lactams, sulfamides, lincosamides, trimethoprim, and amphenicol may have exceeded the PNEC in China and WPR. Furthermore, the SEAR investigation revealed that antibiotic concentrations exceeded his PNEC for macrolides, fluoroquinolones, trimethoprim, sulfonamides in SEAR’s aquatic habitats and fluoroquinolones in Indian aquatic environments. I was.

The relative contribution of antibiotics to many sources of antibiotic contamination in waterways was identified, including hospitals, municipalities, livestock, and pharmaceutical production. Wastewater and wastewater treatment influents from facilities in SEAR, WPR, India, and China were shown to have the highest expected threshold concentrations of most antibiotics and most likely to exceed antibiotic levels. I was. In aquatic habitats, the most significant levels and potential antibiotic concentrations above the PNEC were found for ciprofloxacin in Chinese tap or drinking water and WPR when the 95th percentile was included.

Overall, the amounts of antibiotic residues observed in SEAR and WPR effluents and wastewater treatment plants are likely hotspots for the development of antibiotic resistance, with potential impacts on human health from exposure from drinking-water. cause concern. These results will help decision makers target risk reduction strategies for environmental residues of important antibiotics in high-risk regions and focus research efforts on these global regions.