Enterococcus faecalis colonizes and forms persistent biofilm microcolonies on undamaged endothelial surfaces in a rabbit endovascular infection model

Invasion of pancreatic ductal epithelial cells by Enterococcus faecalis is mediated by fibronectin and enterococcal fibronectin-binding protein A

The poor prognosis of pancreatic cancer is often attributed to difficulties of early detection due to a lack of appropriate risk factors. Previously, we demonstrated the presence of Enterococcus faecalis (E. faecalis) in pancreatic juice and tissues obtained from patients with cancers of the duodeno-pancreato-biliary region, suggesting the possible involvement of this bacterial species in chronic and malignant pancreatic diseases. However, it remains unclear if and how E. faecalis can infect pancreatic ductal cells. In this study, we used immortalized normal human pancreatic ductal epithelial cells (iPDECs) and pancreatic ductal cancer cell lines to demonstrate that E. faecalis adheres to and invades pancreatic ductal lineage epithelial cells. Inhibitors of micropinocytosis or clathrin- or caveolae-mediated endocytosis suppressed iPDEC invasion by E. faecalis. Mechanistically, bacterial expression of enterococcal fibronectin-binding protein A (EfbA) was correlated with adhesive potential of E. faecalis strains. Knockout of fibronectin 1, a binding partner of EfbA, in iPDECs resulted in suppressed E. faecalis adhesion and invasion, suggesting the importance of the EfbA-fibronectin axis in infection of pancreatic ductal epithelial lineage cells. Overall, these results suggest that E. faecalis can colonize pancreatic tissue by infecting iPDECs, at least in part, via the expression of the cell adhesion factor EfbA.

Aortic and Mitral Valve Endocarditis-Simply Left-Sided Endocarditis or Different Entities Requiring Individual Consideration?-Insights from the CAMPAIGN Database

Background: Aortic valve infective endocarditis (AV-IE) and mitral valve infective endocarditis (MV-IE) are often grouped together as one entity: left-sided endocarditis. However, there are significant differences between the valves in terms of anatomy, physiology, pressure, and calcification tendency. This study aimed to compare AV-IE and MV-IE in terms of patient characteristics, pathogen profiles, postoperative outcomes, and predictors of mortality. Methods: We retrospectively analyzed data from 3899 patients operated on for isolated AV-IE or MV-IE in six German cardiac surgery centers between 1994 and 2018. Univariable and multivariable analyses were performed to analyze the risk factors for 30 day and 1 year mortality. A Log-rank test was used to test for differences in long-term mortality. Results: Patients with MV-IE were more likely to be female (41.1% vs. 20.3%.; p < 0.001). Vegetation was detected more frequently in the MV-IE group (66.6% vs. 57.1%; p < 0.001). Accordingly, the rates of cerebral embolic events (25.4% vs. 17.7%; p < 0.001) and stroke (28.2% vs. 19.3%; p < 0.001) were higher in the MV-IE group. Staphylococci had a higher prevalence in the MV-IE group (50.2% vs. 36.4%; p < 0.001). Patients with MV-IE had comparable 30 day mortality (16.7% vs. 14.6%; p = 0.095) but significantly higher 1 year mortality (35.3% vs. 29.0%; p < 0.001) than those with AV-IE. Kaplan-Meier survival analysis showed significantly lower long-term survival in patients with MV-IE (log-rank p < 0.001). Conclusions: Due to the relevant differences between MV-IE and AV-IE, it might be useful to provide individualized, valve-specific guideline recommendations rather than general recommendations for left-sided IE.

Enterococcal-host interactions in the gastrointestinal tract and beyond

The gastrointestinal tract (GIT) is typically considered the natural niche of enterococci. However, these bacteria also inhabit extraintestinal tissues, where they can disrupt organ physiology and cause life-threatening infections. Here, we discuss how enterococci, primarily Enterococcus faecalis, interact with the intestine and other host anatomical locations such as the oral cavity, heart, liver, kidney, and vaginal tract. The metabolic flexibility of these bacteria allows them to quickly adapt to new environments, promoting their persistence in diverse tissues. In transitioning from commensals to pathogens, enterococci must overcome harsh conditions such as nutrient competition, exposure to antimicrobials, and immune pressure. Therefore, enterococci have evolved multiple mechanisms to adhere, colonize, persist, and endure these challenges in the host. This review provides a comprehensive overview of how enterococci interact with diverse host cells and tissues across multiple organ systems, highlighting the key molecular pathways that mediate enterococcal adaptation, persistence, and pathogenic behavior.

Revisiting ESKAPE Pathogens: virulence, resistance, and combating strategies focusing on quorum sensing

The human-bacterial association is long-known and well-established in terms of both augmentations of human health and attenuation. However, the growing incidents of nosocomial infections caused by the ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter sp.) call for a much deeper understanding of these organisms. Adopting a holistic approach that includes the science of infection and the recent advancements in preventing and treating infections is imperative in designing novel intervention strategies against ESKAPE pathogens. In this regard, this review captures the ingenious strategies commissioned by these master players, which are teamed up against the defenses of the human team, that are equally, if not more, versatile and potent through an analogy. We have taken a basketball match as our analogy, dividing the human and bacterial species into two teams playing with the ball of health. Through this analogy, we make the concept of infectious biology more accessible.

Horizontal Gene Transfer of Antibiotic Resistance Genes in Biofilms

Most bacteria attach to biotic or abiotic surfaces and are embedded in a complex matrix which is known as biofilm. Biofilm formation is especially worrisome in clinical settings as it hinders the treatment of infections with antibiotics due to the facilitated acquisition of antibiotic resistance genes (ARGs). Environmental settings are now considered as pivotal for driving biofilm formation, biofilm-mediated antibiotic resistance development and dissemination. Several studies have demonstrated that environmental biofilms can be hotspots for the dissemination of ARGs. These genes can be encoded on mobile genetic elements (MGEs) such as conjugative and mobilizable plasmids or integrative and conjugative elements (ICEs). ARGs can be rapidly transferred through horizontal gene transfer (HGT) which has been shown to occur more frequently in biofilms than in planktonic cultures. Biofilm models are promising tools to mimic natural biofilms to study the dissemination of ARGs via HGT. This review summarizes the state-of-the-art of biofilm studies and the techniques that visualize the three main HGT mechanisms in biofilms: transformation, transduction, and conjugation.