食品科学 ›› 2021, Vol. 42 ›› Issue (2): 121-127.doi: 10.7506/spkx1002-6630-20191112-162

• 生物工程 • 上一篇    下一篇

抗耐药性大肠杆菌乳酸菌的筛选及抑菌机制

孙悦,刘佳伊,陈璐,杜宏,白凤翎,吕欣然,张德福,郭晓华,励建荣   

  1. (1.渤海大学食品科学与工程学院,辽宁省食品安全重点实验室,生鲜农产品贮藏加工及安全控制技术国家地方联合工程研究中心,大连工业大学和渤海大学海洋食品精深加工关键技术省部共建协同创新中心,辽宁 锦州 121013;2.山东美佳集团有限公司,山东 日照 276800)
  • 出版日期:2021-01-18 发布日期:2021-01-27
  • 基金资助:
    “十三五”国家重点研发计划重点专项(2017YFD0400106)

Screening of Lactic Acid Bacteria for Antagonistic Activity against Drug-Resistant Escherichia coli and Underlying Mechanism

SUN Yue, LIU Jiayi, CHEN Lu, DU Hong, BAI Fengling, LÜ Xinran, ZHANG Defu, GUO Xiaohua, LI Jianrong   

  1. (1. Food Safety Key Lab of Liaoning Province, National & Local Joint Engineering Research Center of Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Collaborative Innovation Center of Seafood Deep Processing, Dalian Polytechnic University, Bohai University, College of Food Science and Technology, Bohai University, Jinzhou 121013, China; 2. Shandong Meijia Group Co. Ltd., Rizhao 276800, China)
  • Online:2021-01-18 Published:2021-01-27

摘要: 筛选对耐药性大肠杆菌(Escherichia coli)拮抗活性较强的乳酸菌,并探究其作用机制。采用牛津杯打孔法筛选对耐药性E. coli具有抑制活性的乳酸菌,并通过生理生化实验和16S rDNA序列对其进行鉴定。通过测定阿奇霉素、乳酸菌粗提物、乳酸菌粗提物和阿奇霉素共同作用对耐药性E. coli电导率、胞外蛋白、紫外吸收物质等指标的影响,探究乳酸菌粗提物对耐药性E. coli的抑菌机制。结果表明:菌株XCT1-1对耐药性E. coli的抑菌直径达20.31 mm,且被鉴定为植物乳杆菌。乳酸菌XCT1-1粗提物、乳酸菌XCT1-1粗提物和阿奇霉素共同处理耐药性E. coli 10 h后,导致其胞外电导率分别增加20.54%、21.93%,胞外蛋白含量增加25.24%、27.93%,紫外吸收物质含量增加63.56%、77.12%。经扫描电镜观察,用乳酸菌XCT1-1粗提物、乳酸菌XCT1-1粗提物和阿奇霉素共同处理后,耐药性E. coli细胞壁和细胞膜被破坏,前者菌体表面出现褶皱,后者菌体细胞整体结构坍塌。结果表明,乳酸菌XCT1-1粗提物、乳酸菌XCT1-1粗提物和阿奇霉素共同作用于耐药性E. coli,都是通过膜损伤发挥拮抗作用,且乳酸菌粗提物提高了阿奇霉素对耐药性E. coli的敏感性。

关键词: 耐药性大肠杆菌;乳酸菌;拮抗;筛选与鉴定;抑菌机制

Abstract: The aims of this study were to screen lactic acid bacteria (LAB) strains isolated from pickled Chinese cabbage for antagonistic activity against drug-resistant Escherichia coli, and to explore the underlying mechanism of action. Six target strains were selected by the oxford cup agar well diffusion method, among which strain XCT1-1 exhibited the largest diameter of inhibition zone against drug-resistant E. coli and was identified by physiological and biochemical tests and 16S rDNA sequence analysis. To shed light on the antibacterial mechanism of the ethyl acetate extract of the cell-free culture supernatant of XCT1-1 against drug-resistant E. coli, the effect of treatment with azithromycin and/or the culture supernatant extract on the electrical conductivity and extracellular proteins, and ultraviolet (UV) absorbing materials of drug-resistant E. coli. The results showed that the diameter of inhibition zone of strain XCT1-1 against drug-resistant E. coli was 20.31 mm and it was identified as Lactobacillus plantarum. After 10 h treatment with the culture supernatant extract of XCT1-1 alone and combined with azithromycin, the electrical conductivity increased by 20.54% and 21.93%, the content of extracellular protein by 25.24% and 27.93%, and the content of UV absorbing materials by 63.56% and 77.12%, respectively. The scanning electron microscope (SEM) images showed that the cell wall and membrane of drug-resistant E. coli were damaged by the culture supernatant extract alone and in combination with azithromycin. The bacterial cell surface became wrinkled after the former treatment, while the latter treatment resulted in the collapse of the cell structure. These results indicated that the culture supernatant extract of XCT1-1, azithromycin and their combination exerted antagonistic effects by damaging the cell membrane. In addition, the culture supernatant extract of strain XCT1-1 increased the susceptibility of drug-resistant E. coli to azithromycin.

Key words: drug-resistant Escherichia coli; lactic acid bacteria; antagonistic effect; screening and identification; antibacterial mechanism

中图分类号: