Novel thiazolinyl-picolinamide based palladium(II) complex-impregnated urinary catheters quench the virulence and disintegrate the biofilms of uropathogens

Abstract

Pseudomonas aeruginosa and Serratia marcescens are prominent members belonging to the group of ESKAPE pathogens responsible for Urinary Tract Infections (UTI) and nosocomial infections. Both the pathogens regulate several virulence factors, including biofilm formation through quorum sensing (QS), an intercellular communication mechanism. The present study describes the anti-biofilm and QS quenching effect of thiazolinyl-picolinamide based palladium(II) complexes against P. aeruginosa and S. marcescens. Palladium(II) complexes showed quorum sensing inhibitory potential in inhibiting swarming motility behaviour, pyocyanin production and other QS mediated virulence factors in both P. aeruginosa and S. marcescens. In addition, the establishment of biofilms was prevented on palladium (II) coated catheters. Overall, the present study demonstrates that thiazolinyl-picolinamide based palladium (II) complexes will be a promising strategy to combat device-mediated UTI infections.     

铜绿假单胞菌lasI,rhlI基因功能缺陷株的构建和生物学功能验证

构建铜绿假单胞菌lasI,rhlI基因功能缺陷株,为进一步阐明氦氧饱和高气压暴露条件诱导lasI,rhlI基因介导铜绿假单胞菌毒力调节的分子机制研究奠定基础。用双亲株接合转移法删除lasI,rhlI基因ORF编码区,通过RT-PCR方法验证目标基因编码序列mRNA的缺失;通过对细菌生长增殖能力、弹性蛋白酶代谢活性和细菌绿脓菌素分泌能力等表型的测定,验证目标基因编码序列缺失后的基因调节功能的缺陷。结果表明成功构建铜绿假单胞菌lasI,rhlI基因功能缺陷株,可作为进一步研究的基因工程菌。     

酰基高丝氨酸内脂合成酶LasI对禽致病性大肠杆菌生物学特性的影响

【背景】禽致病性大肠杆菌(Avian pathogenic Escherichia coli, APEC)是禽类主要病原菌之一,群体感应(Quorumsensing,QS)系统可通过信号分子调控其生物学特性。在APEC中信号分子AHL对其生物学特性的影响目前尚不清楚。【目的】研究信号分子AHL对APEC生物学特性的影响。【方法】将含铜绿假单胞菌酰基高丝氨酸内脂合成酶(Acyl-homoserine-lactone synthase,lasI)基因的表达质粒转化至APEC菌株DE17中,构建重组菌株DE17-lasI,利用LasI在DE17中合成AHL。比较野生株和重组菌株产生AHL信号分子、生长特性、生物被膜形成能力、运动性以及耐药性等生物学特性的差异;运用Real-timePCR技术,比较野生株和重组菌株中与生物被膜形成、运动性以及毒力因子相关基因的转录水平。【结果】对重组菌株AHL信号分子检测表明,DE17-lasI能够产生AHL信号分子,与野生株DE17相比,DE17-lasI生物被膜形成能力和运动性显著降低(P0.01),但其生长特性和耐药性无显著变化(P0.05);Real-time PCR检测结果表明,重组菌株的毒力因子fimH转录水平上调了58.8倍,而ompA、iss分别下调了95.4%、77.3%。与生物被膜形成相关基因agn43下调了75%,鞭毛合成基因flhA下调了80.8%。此外,AHL受体sdiA的转录水平上调了19.8倍。【结论】转化lasI至APEC中,能促进其在APEC中合成信号分子AHL,并显著影响APEC的部分生物学特性,为进一步探讨AHL型群体感应系统对APEC的调控作用提供参考。