单增李斯特菌TatD基因缺失菌株的生物学特性研究

Biological characterization of the TatD gene mutant strain of Listeria monocytogenes

为探究TatD基因缺失对单增李斯特菌生物学特性的影响,本研究对缺失菌株LM10403sΔTatD的生化特性、生长特性、生物被膜、环境适应性、黏附、侵袭、增殖、耐药性、溶血特性和毒力等生物学特性进行研究。结果显示,LM10403sΔTatD与亲本菌株LM10403s的生化特性和生长特性均无明显差异。LM10403sΔTatD保留了LM10403s对温度、H_(2)O_(2)和EtOH的适应性,并且对巨噬细胞Raw264.7的黏附、侵袭和增殖没有发生明显改变。但与LM10403s相比,LM10403sΔTatD对高温(54℃)、酸性和苯扎溴铵的耐受性以及对头孢曲松的耐药性和胞外分泌蛋白的溶血特性均有所降低,而生物被膜形成能力有所提升。LM10403sΔTatD腹腔注射感染6周龄小鼠的LD_(50)为2.58×10^(6)CFU,毒力稍低于LM10403s。上述结果表明,TatD基因缺失对单增李斯特菌LM10403s的生物学特性整体无明显影响,部分环境适应性和溶血特性有所降低,而生物被膜形成有所增加,为进一步探究TatD在单增李斯特菌与宿主互作过程中的作用奠定基础。

To explore the effect of Tat D gene deletion on the biological properties of Listeria monocytogenes,the biological properties of the Tat D mutant LM10403sΔTat D,including growth characteristics,biofilm formation,environmental adaptation,adhesion,invasion,proliferation,drug resistance,hemolytic properties and virulence were investigated.The results showed that the LM10403sΔTat D was no significant difference in the biochemical and growth characteristics with the parent strain LM10403s.The LM10403sΔTat D retained the adaptation to temperature,H_(2)O_(2) and Et OH,and had no significant change in adhesion,invasion and proliferation of Raw264.7.Compared with the parent strain LM10403s,the LM10403sΔTat D showed that the resistance to high temperature(54℃),acid and benzalkonium bromide as well as resistance to ceftriaxone and haemolytic properties of extracellular secretory proteins were reduced,while the biofilm formation ability was improved.The LD_(50)of the LM10403sΔTat D was 2.58×10^(6)CFU in 6-week-old mice infected by intraperitoneally,which was slightly less than the LM10403s.The above-mentioned results showed that,on the whole,the deletion of Tat D gene had no significant effect on the overall biological properties of Listeria monocytogenes LM10403s,and some environmental adaptability and haemolytic properties had reduced,while biofilm formation had increased,laying the foundation for further investigation of the role of Tat D in the interaction between Listeria monocytogenes and the host.