The concentrations of antibiotic residues found in wastewater and wastewater treatment plants of the WHO Western Pacific region (WPR) and the South-East Asia region (SEAR) can contribute to the emergence and spread of antibiotic resistance. So concludes a study published by The Lancet Planetary Health. Researchers have analyzed data gathered between 2006 and 2019 in these vast Asian regions, which include China and India, two of the world’s largest producers and consumers of antibiotics.
Interestingly, 92 antibiotics were found in the WPR, whereas 45 were detected in the SEAR. Antibiotic concentrations exceeding the level considered safe for resistance development were observed in wastewater and influent of wastewater treatment plants. «That probably means that they serve as potential hotspots for the development of multidrug-resistant bacteria», points Roberto Díez, CEO of Telum Therapeutics. «Up to 90% of antibiotics administered to humans and animals are excreted into waste streams, through urine and feces. However, wastewater plants only partially remove these residues. Therefore, antibiotics are considered emerging contaminants of aquatic environments and can promote selection and transfer of resistance genes among bacteria».
Threat to human health can also come from tap water. According to the analysis, drinking water in China and the WPR had the highest likelihood of antibiotic ciprofloxacin levels exceeding the threshold considered safe for resistance development. To note, in the WPR and SEAR regions about 80–90% of wastewater is released untreated into water sources, which contributes to human exposure to antibiotic residues. «Additionally, drinking contaminated water could lead to antibiotic-resistant bacteria infections and colonization, resulting in an increase in morbidity and mortality. Is a fish biting its own tail», warns Díez.
Although their work has some limitations, such as a lack of data from many of the countries in the regions and the fact that only studies written in English were included in the analysis, researchers hope that findings could guide decision-makers to undertake well-directed actions toward monitoring and controlling antibiotic residues. They also trust that results help in prioritizing future areas of research on antibiotics and antibiotic resistance in aquatic environments.
«Anthropogenic sources, like city wastewater, are a major burden of bacteria and multidrug-resistant microbes. At Telum Therapeutics, we look for bacteriophages and their lytic enzymes, called endolysins, that prevail in bacterial populations extracted from these sources», declares Roberto Díez. «Our goal is to learn from nature and construct engineered phage lytic enzymes with enhanced antimicrobial activities, from the selection of the best properties of natural enzymes. We are committed to fighting against the growing threat of antibiotic resistance, as well as raising awareness about the proper use of antibiotics and treatment of their waste».
Nada Hanna, Ashok J Tamhankar, Cecilia Stålsby Lundborg. Antibiotic concentrations and antibiotic resistance in aquatic environments of the WHO Western Pacific and South-East Asia regions: a systematic review and probabilistic environmental hazard assessment. The Lancet Planetary Health, 2023; 7 (1): e45 DOI: 10.1016/S2542-5196(22)00254-6