Multigenerational and transgenerational effects of ciprofloxacin on the reproduction of Enchytraeus crypticus

Abstract

Ciprofloxacin (CIP) is an antibiotic used in both human and veterinary medicine. Because it is only partially metabolized, it has been found in sewage sludge, manure, and agricultural soils. Therefore, due to the high persistence and low mobility of CIP in soil, we aimed to evaluate its long-term effect on Enchytraeus crypticus. Three multigenerational and one transgenerational test were performed according to OECD 220 guidelines (2016) on sandy clay soil. The concentrations tested were 0.1, 1.0, 10.0, 100.0, 1000.0 and 5000.0 mg kg⁻¹ dry soil. For F1, statistical analysis showed differences between the control and all concentrations tested, but no differences among the concentrations. For F2, there was a difference between control and 10 mg Kg ⁻¹ and for 10.0 mg Kg ⁻¹ compared to 0.1, 1.0 and 5000.0 mg Kg ⁻¹. For F3, no statistical difference was observed between any of the concentrations. When comparing the generations among themselves, there were significant differences between F1 and F2 and F1 and F3 for all concentrations. For the transgenerational test, there was no statistical difference between the control and the concentrations tested, nor among the concentrations. We verified a negative effect of CIP on the reproduction of E. crypticus for the first generation, which could be related to oxidative stress, DNA damage and clay content. We also verified that the organisms could develop a tolerance to CIP and that the effects of high clay content could outweigh the effects of CIP in long-term exposure. Due to the high persistence and low mobility of CIP on soil, it may affect other organisms and promote antibiotic resistant genes (ARGs) regardless of E. crypticus tolerance. Therefore, we strongly recommend further studies focusing on long-term effects on different organisms, with a molecular approach, and in different soil types.