The occurrence of antimicrobials in the environment from discharges of wastewater treatment plants, and from the land-application of antibiotic-laden manure from animal agriculture is a critical global issue because these residues have been associated with the increased emergence of antibiotic resistance in the environment. Fluoroquinolones, macrolides, sulfonamides, and tetracyclines are approved for use in food-producing animals and are currently actively marketed. The problem is that these drugs are also considered to be important in human medicine, and their continued use for agricultural purposes may affect their efficacy in humans. Also, even though certain drugs such as ciprofloxacin, have already been banned for agricultural use in the US, they are still being used in other countries where there are no such regulations. In order to contribute to an improved understanding of antimicrobial resistance spread, a targeted analysis was performed to determine the levels of antibiotics in WWTPs and surface waters from four countries (Hong Kong, India, Philippines, and the United States) using LC-MS/MS. Results showed that the levels and composition of antimicrobials differ per country, with greater concentrations detected in Hong Kong, India and the Philippines, and lower levels in the United States. Ciprofloxacin was the most detected antibiotic and was found in all countries with concentrations from 23 to 2641 ng/L. Clarithromycin and Anhydro – Erythromycin were also commonly detected with concentrations from 4 to 877 ng/L, and 3 to 467 ng/L, respectively. High-resolution mass spectrometry was also used to do an untargeted analysis to find out what other environmentally significant compounds may be present in these samples.

Global reconnaissance of antimicrobial residues in wastewater and surface waters

256th National Meeting (2018)

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