低营养浓度培养基分离培养生物膜中的细菌及其鉴定

室内潮湿环境固体表面很容易形成细菌生物膜,这些生物膜生长在不易清除或不被人注意的固体表面,研究这一类生物膜中的细菌类群可以了解其中是否滋生着对人体健康有威胁性的致病菌或条件致病菌。选择某公共浴室内塑料表面生长的生物膜作为分离培养对象,同时使用实验室最常用的LB培养基及其10倍稀释培养基(LB/10)作为分离培养基。结果表明在LB培养基上生长的细菌类群相对单一,并且有单一类群占优势或抑制其他类群生长的现象;而在LB/10培养基上生长的细菌具有更丰富的多样性,并且各类菌的数量分布较均匀,没有出现LB培养基中一种细菌占绝对生长优势的现象。对LB/10上生长的8个菌株的16SrDNA片段序列进行测定和系统发育分析,发现与所分离的细菌系统发育相近的包括多株人体临床分离的病原菌以及未培养细菌(Uncultured bacterium)。

Isolation and Identification of Bacteria from Biofilm with Culture Medium of Low Nutrient Concentration

On the solid surface of indoor moist environment bacteria grow to form biofilms easily, which are hard to remove because of its high adhesion. It is of great microbiological safety significance to research bacteria in such kind of biolfilms. Here we isolated bacteria from biofilm growing on solid surface of a public bathroom with Luria Bertani medium (LB) and its 10-fold diluted medium (LB/10). We found that the biodiversity of bacteria growing on LB/10 was better than that of LB. Furthermore one species of bacterium overgrowing other bacteria phenomena was observed on LB but not on LB/10. Eight strains of bacteria isolated with LB1/10 were identified by 16S rDNA analysis. They are clustered with some clinical isolates and uncultured bacteria. Considering the growing environment of these bacteria we also tested their detergent-degrading ability, and found that they could decrease the quantity of foam caused by detergent.