Effect of antibiotics on sedimentary microbiota as characterized by biomarker analysis.

抗生素既可用于治疗，也可用于预防治疗。由于浪费饲料和一些抗生素的低消化效率，很大一部分药物可以释放到环境中并沉积到沉积物中。抗生素也被用来治疗孵化场的幼虫。在含有链霉素的海水中处理贝类幼体后，海水已排放到邻近的海岸环境中。因此，抗生素的使用及其在沉积物中的积累可能会影响自然沉积微生物区系。为了了解抗生素对沉积物微生物生物量及其群落结构的影响，对添加不同浓度链霉素的沉积物进行了磷脂酯连接脂肪酸(PLFA)分析，沉积物参数在培养过程中没有明显变化。海水中的链霉素浓度高于沉积物中的浓度。此外，由于链霉素的加入，在潜伏期内链霉素的浓度增加。根据总PLFA计算，在添加链霉素的所有三个浓度的沉积物中，沉积物微生物生物量都有所下降。微生物生物量比对照下降了20ppm、10ppm和5ppm。在培养结束时，沉积物(10ppm和20ppm链霉素)中的总PLFA水平要么很高，要么与对照值相当，表明沉积物微生物种群可能已经产生了抗生素耐药性。不同浓度链霉素的底泥中PLFA的分布模式不同。PLFA图谱的聚类分析揭示了链霉素修正后底泥微生物群落的变化。多维比例图的结果还表明，由于链霉素的添加和自然微生物区系的破坏，PLFA图谱发生了变化。

Antibiotics are used in both therapeutic and prophylactic treatment of the stocks. Because of wasted feed and low digestive efficiencies of some antibiotics, a substantial fraction of the drug can be released to the environment and is deposited to the sediment. Antibiotics are also used to treat the larvae in hatcheries. After treating the shellfish larvae in seawater containing streptomycin, the seawater has been discharged into the adjacent coastal environment. Thus antibiotic use and its accumulation in the sediment may influence the natural sedimentary microbiota. In order to know the impact of antibiotics on sedimentary microbial biomass, and its community structure, phospholipid ester-linked fatty acid(PLFA)analysis of sediment supplemented with different concentrations of streptomycin was carried out.Sediment parameters did not show significant changes during the incubation. Concentrations of streptomycin in seawater were higher than that in sediments. Furthermore, concentrations of streptomycin increased during the incubation period due to the addition of streptomycin. Sedimentary microbial biomass, as calculated by total PLFA, was decreased in all the three concentrations of streptomycin added sediments. The decrease of microbial biomass over control was in the order of 20 ppm > 10ppm > 5ppm. At the end of the incubation, levels of total PLFA in sediments(10 and 20 ppm streptomycin)were either high or comparable to the control values indicating that sedimentary microbial populations might have developed antibiotic resistance. The pattern of PLFA groups in sediments was different among the three concentrations of streptomycin used. Cluster analysis of PLFA profiles revealed the changes in microbial communities of sediments amended with streptomycin. The results of multidimensional scaling plot also indicated changes in PLFA profiles due to the addition of streptomycin and also disruption of the natural microbiota.