Estimating antibiotics use in major cities in China through wastewater-based epidemiology

Antibiotics have been widely used for disease treatment and may pose adverse effects on human health due to increasing presence of antibiotic-resistant genes in environment. Therefore, it is important to understand antibiotic use in a specific region or country. China is a major producer of antibiotic and has a large number of consumers. In this work, wastewater samples were collected from 76 wastewater treatment plants in 31 major cities covering all of the geographic regions of China. Concentrations of eight metabolites of sulfonamide, quinolone and macrolide antibiotics were determined. The consumption levels of corresponding antibiotics were estimated based on wastewater-based epidemiology (WBE) approach. Desmethyl ofloxacin, desethylene norfloxacin, desmethyl azithromycin and N⁴-acetyl sulfamethoxazole were detected in all or the overwhelming majority of wastewater samples. The estimated ∑8Antibiotics consumption levels ranged from 275.1 ± 139.4 mg/1000 inh/d (Nanchang) to 3860.9 ± 1332.3 mg/1000 inh/d (Harbin) with a mean level of 1170.0 ± 452.1 mg/1000 inh/d. Quinolones accounted for the highest proportion (74.3%, national average contribution) in the total consumption level, with norfloxacin being the dominant one (38.4%), followed by ofloxacin (29.1%) and ciprofloxacin (6.8%). The ∑8Antibiotics consumption level in northern China (1517.0 ± 1022.8 mg/1000 inh/d) was statistically higher than the level in southern China (1060.7 ± 989.1 mg/1000 inh/d) (t-test, p < 0.05). In contrast, no significant difference was found between eastern (1256.2 ± 1105.1 mg/1000 inh/d) and western China (988.3 ± 474.5 mg/1000 inh/d) (t-test, p > 0.05). The overview of antibiotics consumption derived from this work can serve as a baseline to assess the implementation of related plans/policies in China.