食品科学 ›› 2019, Vol. 40 ›› Issue (19): 1-7.doi: 10.7506/spkx1002-6630-20181018-193

• 基础研究 •    下一篇

酸应激对大肠杆菌O157:H7生物菌膜形成的影响

王娴静,董晨,禹金龙,胡洁,付文静,张苏,江芸   

  1. (1.南京师范大学食品与制药工程学院,江苏 南京 210023;2.江苏省疾病预防控制中心,江苏 南京 210009)
  • 出版日期:2019-10-15 发布日期:2019-10-25
  • 基金资助:
    国家自然科学基金面上项目(31671915);江苏省“六大人才高峰”项目(NY-080)

Effect of Acid Stress on Biofilm Formation of Escherichia coli O157:H7

WANG Xianjing, DONG Chen, YU Jinlong, HU Jie, FU Wenjing, ZHANG Su, JIANG Yun   

  1. (1. School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, China; 2. Jiangsu Provincial Center for Disease Control and Prevention, Nanjing 210009, China)
  • Online:2019-10-15 Published:2019-10-25

摘要: 本实验探究较长时间酸应激对大肠杆菌O157:H7生物菌膜形成的影响。首先采用微孔板联合结晶紫染色法比较大肠杆菌O157:H7不同菌株黏附性能差异,分析不同黏附力菌株菌膜形成曲线,进而选择代表菌株采用平板计数法分析在较长时间酸应激时其菌膜的形成规律,最后采用共聚焦激光扫描显微镜(confocal laser scanning microscope,CLSM)比较黏附力不同的菌株在酸性环境下菌膜形态结构变化。结果表明,14 株菌株黏附能力有差异;不同黏附力菌株均在2 h开始产生黏附现象,但菌膜形成曲线有明显差异。以中等黏附力菌株ATCC43895作为代表菌株进行酸应激实验,结果表明pH值越低菌膜形成量越少,pH值相同时乳酸对浮游菌数和菌膜形成的抑制效应显著高于盐酸(P<0.05)。CLSM观察结果表明,成膜能力较强的菌株J29和较弱的菌株CICC21530在中性和酸性培养液中均能形成一定结构的生物菌膜,但前者的菌膜形成量多于后者,酸性条件对成膜过程有抑制作用。提示乳酸能有效抑制大肠杆菌O157:H7菌膜形成过程,可为食品实际加工中该菌菌膜的消除技术提供科学思路。

关键词: 大肠杆菌O157:H7, 生物菌膜, 乳酸, 应激

Abstract: The aim of this study was to investigate the effect of long-term acid stress on biofilm formation (BF) of Escherichia coli O157:H7. Firstly, the adhesion capacities of different strains were compared by using microwell plate-crystal violet staining method and the BF curves of strains with different adhesion capacities were analyzed. Secondly, one representative strain was selected to investigate the effect of long-term acid stress on BF using plate-counting method. Finally, the changes in biofilm microstructure of the adhesive strains under acidic condition were observed using a confocal laser scanning microscope (CLSM). The results showed that adhesion capacity varied among 14 investigated strains. The BF curves of the adhesive strains were different although they all began to form biofilm after 2 h of cultivation. The results of acid stress showed that the BF of ATCC43895, a representative strain with medium adhesion ability, was inhibited by acid, the lower pH could result in lower BF, and the inhibitory effect of lactic acid on BF was significantly higher than that of hydrochloric acid (P < 0.05). CLSM results showed that weakly adhesive strain CICC21530 and strongly adhesive strain J29 were able to form biofilm under acidic and neutral conditions, and the latter had a higher biofilm production than did the former. Acidic condition inhibited the BF process. Our findings demonstrated the inhibitory effect of lactic acid on BF of E. coli O157:H7, which provides scientific evidence for the elimination of the biofilm formed by E. coli O157:H7 in food processing.

Key words: Escherichia coli O157:H7, biofilm, lactic acid, stress

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