健康奶牛生殖道乳酸菌的分离鉴定及其抑菌活性研究

【目的】从健康奶牛生殖道分离筛选益生乳酸菌，为未来防治奶牛子宫内膜炎提供益生菌菌株并为开发防治此病的微生态制剂奠定基础。【方法】采集10份健康奶牛的生殖道分泌物样品，用MRS培养基进行分离培养，通过形态学观察和16S rDNA序列对分离出的菌株进行鉴定，将所得序列结果与NCBI核酸数据库参考菌株进行相似性比对，确定各分离菌株的种属。利用牛津杯法分离筛选出具有较好抑菌活性的菌株，研究这些筛选出的菌株的生长曲线、产酸能力及抗菌药敏感性，并对其主要抗菌物质进行检测。【结果】从10个样品中共分离出13株乳酸菌，经染色镜检和16S rDNA测序分析鉴定出13株乳酸菌，分别为植物乳杆菌11株、殊异肠球菌和鼠肠球菌各1株。单株抑菌试验得到5株对大肠杆菌抑菌能力较好的乳酸菌，5株乳酸菌生长特性及产酸能力均良好，对氨苄西林、四环素、红霉素、利福平、甲氧苄啶、氯霉素和青霉素7种抗菌药物敏感性较强。其中21和35号菌株的抗菌物质为过氧化氢和细菌素，而25、33和34号菌株的抗菌物质除过氧化氢和细菌素外还包括有机酸。【结论】从奶牛生殖道中分离得到的3株乳酸菌有望作为微生态制剂用于奶牛子宫内膜炎的临床防治，其具...

Isolation,Identification and Antibacterial Activity of Lactic Acid Bacteria from Reproductive Tract of Healthy Dairy Cows

【Objective】 It was aimed to isolate and screen probiotic lactic acid bacteria from the reproductive tract of healthy dairy cows,and to provide probiotic strains for the prevention and treatment of dairy cow endometritis in the future,and lay the foundation for the development of microecological preparations for the prevention and treatment of this disease.【Method】 The reproductive tract secretion samples of 10 healthy dairy cows were collected and isolated and cultured with MRS medium.The isolated strains were identified by morphological observation and 16S rDNA sequence.The sequence results were compared with the reference strains on NCBI nucleic acid database to determine the species of each isolated strain.Oxford cup method was used to isolate and screen strains with good antibacterial activity.The growth curve,acid production ability and antimicrobial sensitivity of these screened strains were studied,and their main antibacterial substances were detected.【Result】 A total of 13 strains of lactic acid bacteria were isolated from 10 samples.After staining microscopy and 16S rDNA sequencing analysis,13 strains of lactic acid bacteria were identified as 11 strains of Lactobacillus plantarum,1 strain of Enterococcus specialis and 1 strain of Enterococcus rodentis respectively.5 strains of lactic acid bacteria with good antibacterial ability against Escherichia coli were obtained by single strain antibacterial test.The growth characteristics and acid production ability of the five strains of lactic acid bacteria were good,and they were highly sensitive to ampicillin,tetracycline,erythromycin,rifampicin,trimethoprim,chloramphenicol and penicillin.The antibacterial substances of strains 21 and 35 were hydrogen peroxide and bacteriocin,while the antibacterial substances of strains 25,33 and 34 included organic acids in addition to hydrogen peroxide and bacteriocin.【Conclusion】 Three strains of lactic acid bacteria isolated from the reproductive tract of dairy cows were expected to be used as probiotics in the clinical prevention and treatment of dairy cow endometritis,and its specific prevention and treatment effect needed to be further explored.