Characterizing human exposure to multi-class antibiotics through urine biomonitoring in a Chinese population

The growing threat of antimicrobial resistance to global public health underscores the urgent need for biomonitoring of human exposure to antibiotics in the environment, for which data are currently limited in the general population. In this study, we developed a new and reliable multi-class method, utilizing enzymatic hydrolysis, liquid-liquid extraction (LLE), solid-phase extraction (SPE), and HPLC-MS/MS, to simultaneously analyze 77 antibiotics in human urine. The method was applied to assess antibiotic body burden in 755 individuals from the general population of Shenzhen, China. In these samples, 51 antibiotic compounds were detected, and at least one compound was found in 93% of participants, with up to 13 in a single sample. After excluding outliers, the mean total concentration of antibiotics was 7.77 ng/mL (median: 2.14; P75: 7.65; P95: 35.3). Sulfonamide concentrations were significantly higher in males than in females, and varied notably across age groups. The average estimated daily intakes (EDIs) for 13 frequently detected antibiotics (detection frequency > 5%) ranged from 0.070 to 11.9 ng/kg-bw/day, comparable to dietary-based EDIs derived from antibiotics in drinking water and food samples. These finds indicate that urine is a reliable biological matrix for biomonitoring human exposure to environmental antibiotics and that diet is the predominant exposure route. Further research is warranted to elucidate the health implications of environmental antibiotic exposure, particularly its potential impact on the human gut microbiome. • A broad multi-class analysis method was developed for 77 antibiotics in human urine. • Urinary antibiotic residues were characterized in a group of 755 members of the general Chinese population. • Differences in antibiotic concentrations were observed by gender, age, and across BMI groups. • Estimated daily intakes based on urinary antibiotic levels closely mirrored those derived from dietary exposure data.