Distribution of Ebp pili among clinical and fecal isolates of Enterococcus faecalis and evaluation for human platelet activation

Abstract

Although Enterococcus faecalis is known as normal flora in colon, it is also amongst the most common causative agents of infective endocarditis (IE). Platelet activation resulting from adherence to platelets is an essential step in the pathogenesis of IE. One of the factors proposed in adhesion is endocarditis- and biofilm- associated pili encoded by ebp operon. The aim of this study was to investigate ebp in isolates from different origins and analyze the potential of isolates to activate human platelets of different donors. The ebp distribution was investigated in E. faecalis from different origin infections (n = 103) and fecal flora (n = 20). Then, selected isolates from blood (n = 5), urine (n = 2), and fecal flora (n = 3) were analyzed by flow cytometry assay for the ability to activate platelets of four different donors. No statistically significant difference was found for the ebp presence between infective and fecal isolates. Also, it was found that the ability for platelet activation is independent of the bacterial origin. However, significant difference was found in platelet activation between different donors. The results suggest that the presence or absence of ebp is not a critical factor for platelet activation by E. faecalis isolates. However, host factors seem to contribute in this activity.

Integrated analysis of gut microbiome and host immune responses in COVID-19

“…Moreover, the Enterococcus faecalis was shown to be enriched in severe/critical COVID-19, which was related to enhanced expression of genes related to platelet aggregation and neutrophil degranulation. Previous studies demonstrated that some clinical isolates of Enterococcus faecalis could cause aggregation of human platelets [38] or activate human platelets in vitro [39], while sonicated extract of Enterococcus faecalis could suppress the cell cycle transition and inhibit lymphocytes response [40]. Hence, we assume that the observed dysregulation of certain gut microbes might not be a passenger but a potential driver for the severity of COVID-19.…”

Changes of gut microbiota under different nutritional methods in elderly patients with severe COVID-19 and their relationship with prognosis

“…Specifically, Enterococcus faecium is found to be enriched in severe COVID-19 cases, which is linked to heightened expression of genes associated with platelet aggregation and neutrophil-granulocyte degranulation ( 38 ). Prior research has demonstrated that certain clinical isolated strains of Enterococcus faecium possess the ability to induce human platelet aggregation ( 39 ) or activate human platelets in vitro ( 40 ). Additionally, the ultrasonic extract derived from Enterococcus faecium has been found to impede cell cycle progression and suppress lymphocyte response ( 41 ).…”