Abstract: To investigate the pathogenic mechanism of the cpxAR two‑component gene in Glaesserella parasuis and screen for the deletion‑attenuated strain of Glaesserella parasuis serotype 5，the cpxAR double gene deletion strain（ΔcpxAR） of Glaesserella parasuis serotype 5 clinical isolate（GPS5） was constructed，and the growth characteristics，biofilm formation ability，environmental stress resistance and pathogenicity to guinea pigs were systematically analyzed.The results showed that after cpxAR gene deletion，there was no significant difference in colony morphology and growth rate between ΔcpxAR and its parent strain GPS5，but the biofilm formation ability was significantly weakened，the resistance to osmotic pressure，heat shock，oxidative stress and alkalinity was significantly reduced，and the virulence to guinea pigs was also significantly reduced. In conclusion，the cpxAR gene has no obvious regulatory effect on the growth of GPS5，but it has an important regulatory effect on its biofilm formation，environmental stress resistance and virulence.It lays a foundation for further exploration of the biological functions of the cpxAR two‑component system in Glaesserella parasuis and screening of attenuated strains of Glaesserella parasuis serotype 5.

Key words: Glaesserella parasuis serotype 5, cpxAR gene deletion strain, Growth, Biofilm, Resistance, Virulence

摘要： 为研究cpxAR双组分基因在格拉瑟菌中的致病机制，同时筛选格拉瑟菌血清5型缺失弱毒株，构建格拉瑟菌血清5型临床分离株（GPS5）的cpxAR 双基因缺失株（ΔcpxAR），并对缺失株的生长特性、生物膜形成能力、环境胁迫抗性及豚鼠致病力等生物学特性进行系统研究。结果表明，cpxAR基因缺失后，ΔcpxAR与亲本株GPS5相比，菌落形态和生长速率无明显差异，但生物膜形成能力明显减弱，对渗透压、热休克、氧化应激及碱性胁迫的抗性显著降低，对豚鼠的毒力也显著减弱。综上，cpxAR基因对GPS5的生长无明显调控作用，但对其生物膜形成、环境胁迫抗性及毒力均具有重要调控作用，为深入探究cpxAR双组分系统在格拉瑟菌中的生物学功能，以及筛选格拉瑟菌血清5型弱毒株奠定了基础。

关键词: 格拉瑟菌血清5型, cpxAR基因缺失株, 生长, 生物膜, 抗性, 毒力