Study on dynamics and physiology of antibiotic resistant bacteria in natural environments

了解抗生素耐药菌在自然环境中的动态变化有助于预防其传播。重要的是不仅要考虑耐药细菌，还要考虑耐药基因，因为这些基因能够在不同的细菌之间移动。本研究调查了河流中抗生素耐药基因的分布及细菌对抗生素的反应。污染地点河水中四环素抗性基因多样性高于未污染地点。设计了扩增内酰胺酶基因的PCR引物。用新设计的引物进行PCR检测，可检测河水中多种内酰胺酶基因。采用由河水和形成生物膜的玻璃珠组成的微环境，研究了四环素耐药菌的动态变化。生物成膜细菌的多样性高于自由活菌。细菌可以获得抗生素耐药性并在生物膜中生存。由于抗生素基因的转移和抗生素对细胞渗透性的改变。

Understanding of dynamics of antibiotic resistant bacteria in natural environments contributes to prevention, of their spread. It is important to consider not only resistant bacteria but also resistance genes, because the genes are able to move between different bacteria. In this study distribution of the antibiotic resistance genes in the rivers and bacterial responses to antibiotic were investigated.1. Diversity of tetracycline resistance genes in the river water was higher in the polluted site than in the unpolluted sites.2. The PCR primer sets for amplifying the beta-lactamase genes were designed. Various beta-lactamase genes could be detected in the river water by PCR with newly designed primers.3. Dynamics of tetracycline resistant bacteria was investigated using a microcosm which consisted of river water and glass beads for biofilm formation. Diversity was higher in biofilm forming bacteria than in free living bacteria., Bacteria could acquire antibiotic resistance and survive in a biofilm.because of transfer of antibiotic genes and change of permeability of antibiotics intothe cells.