Effects of antibiotics on soil microbial communities. Effects of veterinary antibiotics on soil microbial communities: Predominance of Rhodanobacter sp. concomitant with increased nitrate reduction

Frequent fertilization of agricultural used land with liquid manure leads to an entry of veterinary pharmaceuticals into soils with the risk of affecting soil microbial communities. In this study, the effect of the antibiotics lincomycin (LIN) and sulfadimidine (SDM) on the microbial community of an agricultural soil was investigated conducting a column experiment. Soil filled columns were steadily treated with LIN or SDM for three weeks. Subsequently, the resulting bacterial communities were cultivated with higher doses of the pharmaceuticals. The bacteria of the soil and the cultivated communities were analysed by Illumina sequencing. Abiotic factors like pH, oxygen saturation and ion concentrations were examined throughout the experiment. Sequence analysis showed, that both the continuous input and the one-time addition of higher doses of LIN or SDM led to changes within community structure and diversity. A significant increase in nitrate reduction in the treatments with LIN and SDM was correlated by a strong growth of bacteria of the genus Rhodanobacter. This leads to the conclusion, that an input of antibiotic residuals into soils can induce shifts within the microbial community structure, fostering the growth of specific bacteria and thus affecting the ecological function of the soil bacterial community.

农用土地频繁施用液态粪肥，会导致兽药类药物进入农田土壤，存在影响土壤微生物群落的风险。本研究通过柱实验，探究了抗生素林可霉素（lincomycin, LIN）与磺胺二甲嘧啶（sulfadimidine, SDM）对某农田土壤微生物群落的影响。将装填有土壤的柱体持续施加LIN或SDM处理三周，随后以更高剂量的上述抗生素，对所得细菌群落进行二次培养。采用Illumina测序（Illumina sequencing）技术，对原始土壤细菌与培养所得的细菌群落进行分析，并全程同步监测了pH值、氧饱和度与离子浓度等非生物因子。序列分析结果表明，无论是持续低剂量施加，还是一次性高剂量添加LIN或SDM，均会导致土壤微生物群落的结构与多样性发生改变。施加LIN与SDM的处理组中，硝酸盐还原能力的显著提升，与红杆菌属（Rhodanobacter）细菌的大量增殖呈显著正相关。据此可得出结论：抗生素残留进入土壤后，可诱导微生物群落结构发生改变，促进特定细菌类群的增殖，进而影响土壤细菌群落的生态功能。