枯草芽孢杆菌的分离鉴定及其特性研究

Isolation, identification, and characterization of Bacillus subtilis

枯草芽孢杆菌是一类好氧、产芽孢、无致病性、无荚膜、能运动的革兰阳性杆状菌,由于其优越的益生特性,常作为生态制剂直接添加到饲料中。从天津周边猪场采集到样品,分离得到供试菌编号为Y33245。通过细菌形态学、生理生化特征和16S rDNA序列测定等方法,对其进行菌株鉴定,并通过药敏试验、耐盐试验、耐胆盐试验、耐人工胃液试验、耐人工肠液等方法进一步研究其生物学特性。试验结果表明:该菌株为枯草芽孢杆菌,对多种抗菌药物表现高度敏感,在人工胃液条件下,存活率可达61.3%;在人工肠液条件下,存活率可达72.6%,具有极强的抗逆性,通过对其生物学特性研究表明,该菌具有良好的生物学特性,可为后续微生态制剂研究提供数据参考。

Bacillus subtilis is a kind of aerobic,spore-producing,non-pathogenic,non-capsular and motile Gram-positive bacilli.Due to its excellent probiotic characteristics,it is often added to feed as probiotics.Samples were collected from pigs of pig farms around Tianjin.After a process of isolation,the experimental bacteria numbered as Y33245 was studied by morphology,physiological and biochemical characteristics and identified by 16S rDNA sequence analysis.Also further experiments studied its characteristics by doing drug sensitive test,salt and cholate resistance test,artificial gastric and intestinal fluid(put the strain into the fluid)test.The final experimental results showed that this was a Bacillus subtilis strain which was highly sensitive to a variety of antimicrobial agents.Its survival rate in artificial gastric and intestinal fluid reached up to 61.3%and 72.6%respectively,which showed its strongly resistant characteristic.Meanwhile its biological characteristic has been studied.All these could provide reference data for the follow-up study on microecological agents.