Xu Dan, Zhang Wei, Zhang Bing, Liao Chongbing, Shao Yongping
Key Laboratory of Biomedical Information Engineering of the Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, China.
Center for Translational Medicine, Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, China.
PeerJ. 2016 Jul 14;4:e2178. doi: 10.7717/peerj.2178. eCollection 2016.
Deficiency in biosynthesis of inner core of lipopolysaccharide (LPS) rendered a characteristic biofilm-forming phenotype in E. coli. The pathological implications of this new phenotype in Shigella flexneri, a highly contagious enteric Gram-negative bacteria that is closely related to E. coli, were investigated in this study. The ΔrfaC (also referred as waaC) mutant, with incomplete inner core of LPS due to deficiency in Hep biosynthesis, was characteristic of strong biofilm formation ability and exhibited much more pronounced adhesiveness and invasiveness to human epithelial cells than the parental strain and other LPS mutants, which also showed distinct pattern of F-actin recruitment. Failure to cause keratoconjunctivitis and colonize in the intestine in guinea pigs revealed that the fitness gain on host adhesion resulted from biofilm formation is not sufficient to offset the loss of fitness on survivability caused by LPS deletion. Our study suggests a clear positive relationship between increased surface hydrophobicity and adhesiveness of Shigella flexneri, which should be put into consideration of virulence of Shigella, especially when therapeutic strategy targeting the core oligosaccharide (OS) is considered an alternative to deal with bacterial antibiotics-resistance.
脂多糖（LPS）内核生物合成缺陷使大肠杆菌呈现出一种独特的生物膜形成表型。本研究对这种新表型在弗氏志贺菌中的病理意义进行了调查，弗氏志贺菌是一种与大肠杆菌密切相关的高传染性肠道革兰氏阴性菌。ΔrfaC（也称为waaC）突变体由于庚糖生物合成缺陷而导致LPS内核不完整，其特点是具有很强的生物膜形成能力，并且与亲本菌株和其他LPS突变体相比，对人上皮细胞表现出更明显的粘附性和侵袭性，同时还表现出不同的F-肌动蛋白募集模式。在豚鼠中未能引起角结膜炎和在肠道中定殖表明，由生物膜形成导致的宿主粘附适应性增加不足以抵消LPS缺失导致的生存适应性损失。我们的研究表明，弗氏志贺菌表面疏水性增加与粘附性之间存在明显的正相关关系，在考虑志贺菌毒力时应考虑这一点，特别是当将针对核心寡糖（OS）的治疗策略视为应对细菌抗生素耐药性的替代方案时。
