Simultaneous inactivation of antibiotic-resistant bacteria and degradation of antibiotic-resistant genes in alkalised human urine.

The coexistence of pharmaceuticals and microorganisms in source separated urine poses a risk for the development of antimicrobial resistance (AMR), especially when urine-based fertilizers are applied to soils. While prior studies have investigated pathogen inactivation in source-separated wastewater matrices, few have evaluated the simultaneous fate of antibiotic-resistant bacteria (ARBs) and their corresponding resistance genes (ARGs) in real urine matrices, particularly under alkaline conditions. Here, we studied the inactivation of β-lactamase-producing and vancomycin-resistant and the degradation of their respective ARGs ( and A) in alkalized, unhydrolyzed urine (pH 10.8 and 12.5) treated with UV (65 W low pressure dichromatic mercury lamp at 185/254 nm), hydrogen peroxide (1.25 g L HO), and their combination (UV/HO). UV/HO treatment resulted in >7 log inactivation of both ARBs, with inactivation rate constants of -0.058 log cfu min (, UV) and -0.093 log cfu min (, UV/HO). In contrast, ARG reduction was limited with UV alone and negligible with HO alone. Gene copy reductions of 3 log10 ( , = -0.055 log10 copies min) and 2 log10 (A, = -0.040 log10 copies min) were observed under UV/HO. Notably, brief storage (>3 h) at pH 12.5 achieved similar ARB inactivation and ARG reduction as 80 min of UV/HO treatment at pH 10.8, offering a low-energy alternative for sanitizing source-separated urine.