luxS基因缺失对禽致病性大肠杆菌O_1、O_2和O_(78)三种血清型分离株的生物学特性影响  

Inactive lux S influence on biological characteristics of O_1, O_2 and O_(78) serotypes isolates in avian pathogenicity Escherichia coli

作　　者：吕小龙[1,2] 胡剑刚 陈兆国[2] 荆雅玮 米荣升[2] 黄燕[2] 王少辉[2] 韩先干[2] 祁克宗[1] 

机构地区：[1]安徽农业大学动物科技学院,安徽合肥230036 [2]中国农业科学院上海兽医研究所,上海200241

出　　处：《微生物学报》2018年第2期238-246,共9页Acta Microbiologica Sinica

基　　金：国家自然科学基金(31370045;31372402;31572546);上海市科技兴农重点攻关项目[沪农科攻字(2015)第1-9号]~~

摘　　要：【目的】LuxS/AI-2型密度群体感应系统产生的自诱导信号分子AI-2(AI-2的产生需要luxS基因编码的Lux S蛋白参与)参与对细菌众多生理功能的调控。探讨luxS对不同血清型禽致病性大肠杆菌(Avian Pathogenicity Escherichia coli,APEC)生物学特性的影响。【方法】本研究以APEC优势血清型APECO_1(O_1血清型)、DE17(O_2血清型)、E940(O_(78)血清型)及其相应luxS缺失株为研究对象,对野生株和缺失株的生长特性、生物被膜形成、rdar(red,dry and rough)形态、运动性和耐药性等特性进行分析。【结果】luxS基因的缺失不影响APEC生长特性,但导致APEC不能产生AI-2;此外,luxS基因的缺失显著降低APECO_1和E940的生物被膜形成(P<0.05),而DE17的生物被膜形成无显著变化。对各菌株的rdar形态和运动性检测结果表明,luxS基因的缺失改变了APECO_1的rdar形态,对DE17和E940并无影响;显著降低了APECO_1和DE17运动能力,对E940并无影响。荧光定量PCR检测结果表明,luxS基因的缺失显著降低APECO_1、DE17和E940与细菌运动性相关的鞭毛基因fli G和fli I的转录水平(P<0.05)。此外,对各菌株的耐药性检测结果表明,luxS基因缺失导致APECO_1对头孢吡肟和丁胺卡那由耐药变为高敏,同时对氯霉素与E940相同由高敏变为耐药,但对DE17的耐药性无显著改变。【结论】luxS对APEC的生物学特性具有重要的调控作用,且这种调控具有菌株特异性。[Objective] LuxS/AI-2-type quorum sensing participates in regulation of bacterial biological properties by AI-2, which is synthesized by the enzymes LuxS （encoded by luxS）. The aim of this study is to elucidate luxS effects on biological characteristics of different serotypes in Avian Pathogenic Escherichia coli （APEC）. ]Methods[ The biological characteristics of 3 APEC strains, including APECO1 （serotype O1）, DE17 （serotype O2） and E940 （serotype 078） and their luxS mutant strains were analysed by growth curve, biofilm-producing, rdar morphology, bacterial motility and sensitivity to antibiotics. ]Results] luxS knockout, eliminating AI-2 formation, had no influence on bacterial growth, but significantly decreased biofilm-producing in E940 and APECO1 （P〈0.05）, without effect on DE17. Results of rdar morphology indicate that the APECO1 strain showed remarkable change in rdar morphology compared with luxS mutant, but no change in DE17 and E940. Moreover, deletion of luxS lead to decreasing the motility of APECO1 and DE17, but no influence on E940 strain. The transcriptional levels offliG andfliI were significantly decreased in APECO1, DE17 and E940 （P〈0.05）. Furthermore, results of drug-resistance indicate that luxS inactivation caused APECO1 resistant to cefepime, amikacin, and sensitive to chloramphenicol. luxS inactivation also caused E940 strain sensitive to chloramphenicol, but no significant effect on drug-resistance of DE17 strain. [Conclusion] LuxS plays a significant role in regulation of biological properties in APEC.

关 键 词：LuxS/AI-2 禽致病性大肠杆菌(APEC) 生物被膜 rdar形态 运动性 耐药性 

分 类 号：S852.61[农业科学—基础兽医学]