Structure–Function Aspects of PstS in Multi-Drug–Resistant Pseudomonas aeruginosa

PLoS Pathogens

Yimei Chen¹  Jerrold R Turner²  Yingmin Wang²  Alexander Zaborin³  Hoylan Fernandez³  Christopher Holbrook³  Irina Morozova³  John C Alverdy³  Olga Zaborina³  Jason Long³ 

[1] Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, United States of America;Department of Pathology, University of Chicago, Chicago, Illinois, United States of America;Department of Surgery, Pritzker School of Medicine, University of Chicago, Chicago, Illinois, United States of America

关键词: Pseudomonas aeruginosa;    Phosphates;    Gastrointestinal tract;    Antibiotic resistance;    Enzyme-linked immunoassays;    Epithelial cells;    Caco-2 cells;    Mouse models;   

DOI  :  10.1371/journal.ppat.0040043

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

The increasing prevalence of multi-drug–resistant (MDR) strains of Pseudomonas aeruginosa among critically ill humans is of significant concern. In the current study, we show that MDR clinical isolates of P. aeruginosa representing three distinct genotypes that display high virulence against intestinal epithelial cells, form novel appendage-like structures on their cell surfaces. These appendages contain PstS, an extracellular phosphate binding protein. Using anti-PstS antibodies, we determined that the PstS-rich appendages in MDR strains are involved in adherence to and disruption of the integrity of cultured intestinal epithelial cell monolayers. The outer surface–expressed PstS protein was also identified to be present in P. aeruginosa MPAO1, although to a lesser degree, and its role in conferring an adhesive and barrier disruptive phenotype against intestinal epithelial cells was confirmed using an isogenic ΔPstS mutant. Formation of the PstS rich appendages was induced during phosphate limitation and completely suppressed in phosphate-rich media. Injection of MDR strains directly into the intestinal tract of surgically injured mice, a known model of phosphate limitation, caused high mortality rates (60%–100%). Repletion of intestinal phosphate in this model completely prevented mortality. Finally, significantly less outer surface PstS was observed in the MPAO1 mutant ΔHxcR thus establishing a role for the alternative type II secretion system Hxc in outer surface PstS expression. Gene expression analysis performed by RT-PCR confirmed this finding and further demonstrated abundant expression of pstS analogous to pa5369, pstS analogous to pa0688/pa14–55410, and hxcX in MDR strains. Taken together, these studies provide evidence that outer surface PstS expression confers a highly virulent phenotype of MDR isolates against the intestinal epithelium that alters their adhesive and barrier disrupting properties against the intestinal epithelium.

【 授权许可】

CC BY