中文摘要：

为了正确评估抗生素残留的环境风险,了解长期受低浓度红霉素污染条件下,水体底泥中红霉素耐受菌群结构的变化特点,采用传统的微生物培养法和分子生物学方法对长期受低浓度红霉素污染的水体底泥中红霉素耐受菌群结构的多样性进行了分析.结果表明：采用传统的培养方法,从底泥中可分离筛选出3株对红霉素有耐受能力的菌株,根据其形态学特征及16S rDNA序列分析,初步鉴定为赖氨酸芽孢杆菌（Lysinibacillussp.）、土壤芽孢杆菌（Solibacillus silvestris）以及蜡样芽孢杆菌（Bacillus cereus）,其中敏感菌蜡样芽孢杆菌经低浓度红霉素诱导对红霉素表现出一定的耐药性.进一步构建底泥耐药菌群16S rDNA克隆文库发现,底泥中红霉素耐受菌群可分为三大类群,其中未获培养的细菌（Uncultured bacterium）在整个文库中比例最大,占65.06%,其次为芽孢杆菌纲（Bacilli）和梭菌纲（Clostridia）,分别占文库比例33.73%和1.20%.文库中可培养的耐药菌优势类群为芽孢杆菌纲,与传统培养方法得到的结果相一致.上述研究表明,在长期受低浓度红霉素污染的环境中,红霉素耐药菌的存在具有一定的广泛性和潜在性,将可能威胁人类健康和生态系统,应当重视其生态风险评价与管理.

英文摘要：

In order to accurately assess the environmental risk of residual antibiotics, the changing of bacterial community structure in the sediment polluted by long-term low concentration of erythromycin was analyzed through the comprehensive traditional and molecular biological methods. The results show that based on the bacterial morphology and 16S rDNA sequence, three erythromycin resistant strains were isolated from the sediment and were identified asLysinibacillussp.,Solibacillus silvestris,andBacillus cereus. Among them,Bacillus cereusshows resistance to erythromycin after exposing to low concentration of erythromycin. Further study by using 16S rDNA clone library found erythromycin resistant bacterial communities in the sediment can be divided into three groups. In the whole library, uncultured bacterium holds the largest proportion, accounting for 65.06% of population, followed byBacilliandClostridia,respectively,accounting for the proportion of 33.73% and 1.20%. The dominant group of the culturable antibiotics resistant bacteria isBacilli,and the results are consistent with those obtained by the traditional method. The study shows that in the long-term low concentration of erythromycin environment, the existence of erythromycin resistant bacteria is extensive, which has a growing threat to human health and ecological risks that needs attention.